Medical Applications User Guide (pdf) - Freescale Semiconductor

Medical Applications
User Guide
TM
freescale.com/medical

“As a practicing surgeon,
my first-hand exposure to the
devices and the industry as a
whole is instrumental in driving
the innovative, high-quality
medical solutions that we
develop here at Freescale.”
—Dr. José Fernández Villaseñor
Freescale product manager,
electrical engineer and practicing
neurosurgeon

freescale.com/medical 3
Introduction
1.1 Freescale Offers Technology for Life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
1.2 Welcome to Freescale Medical Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
1.3 Why Freescale? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Home Portable Medical
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Telehealth Systems .........................................................10
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
3.2 Home Health Hub (HHH) Reference Platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
3.3 Power Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
3.4 Voltage Regulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
3.5 Keypad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
3.6 Touch-Sensing Software Suite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
3.7 How it Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
3.8 Freescale Touch Sensor Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
3.9 PWM Function for a Speaker Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
3.10 Wireless Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
3.11 Introduction to ZigBee Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
3.12 Freescale Solutions with ZigBee Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
3.13 Configuration Diagrams for Freescale ZigBee Transceiver Families . . . . . . . . . . . . . .18
3.14 ZigBee Health Care Profile and IEEE 802.15.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
3.15 Why ZigBee Is Ideal for Wireless Vital Sign Monitoring . . . . . . . . . . . . . . . . . . . . . . . .19
3.16 Freescale Enables ZigBee Health Care Profile for Medical Devices . . . . . . . . . . . . . .19
3.17 Transceivers and Receivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
3.18 Freescale Continua Health Alliance Certified USB Library Software . . . . . . . . . . . . . .20
3.19 Standard Medical USB Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Blood Pressure Monitor .....................................................24
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
4.2 Heartbeat Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
4.3 Systolic and Diastolic Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
4.4 Invasive Blood Pressure Monitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
4.5 Obtaining Pressure Measures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
4.6 Blood Pressure Monitor Reference Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Heart Rate Monitor .........................................................31
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
5.2 Heart Signals Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
5.3 Filters and Amplification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
5.4 Amplifier and Filtering Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
5.5 Obtaining QRS Complexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
5.6 Heart Rate Monitor Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
Blood Glucose Meter .......................................................34
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
6.2 Test Strip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
6.3 Wired and Wireless Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
6.4 Liquid Crystal Display (LCD) Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
Pulse Oximetry .............................................................40
7.1 Theory Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
7.2 Signal Acquisition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
7.3 Circuit Design Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
7.3.1 Circuit LED Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
7.3.2 Signal Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
Activity Monitor. ............................................................44
8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
8.2 Electocardiography (ECG) Acquisition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
8.3 Pedometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
8.4 User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
8.5 Reference Designs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
Hearing Aids. ...............................................................50
9.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50
9.2 Microphone Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51
9.3 Li-ion Battery Charger Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51
9.4 Class D Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
9.5 Digital Signal Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
Freescale Technologies for Home Portable Medical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
Diagnostic and Therapy Devices
10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
10.2 Electrocardiograph and Portable ECG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
10.3 QRS Complex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
10.4 Filtering ECG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
10.5 Electrodes Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
10.6 Display Driver and Touch Screen Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
10.7 Enhanced Multiply-Accumulate (eMAC) Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
10.8 USB Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61
Defibrillators. ...............................................................62
11.1 Automated External Defibrillator (AED) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62
11.2 Circuit for Capacitive Discharge Defibrillators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .63
11.3 Circuit for Rectangular-Wave Defibrillators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .63
Ventilation and Spirometry ..................................................64
12.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64
12.2 System Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65
12.3 Spirometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65
12.4 Graphic LCD MPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66
12.5 Alarm System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67
12.6 Air and Oxygen Blender and Mix Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67
Anesthesia Monitor .........................................................72
13.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .72
13.2 Brief Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
13.3 Pressure Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
13.4 Valve Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
13.5 Principal MCU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
Vital Signs ..................................................................75
14.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75
14.2 Measuring Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76
14.3 ECG Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76
14.4 Pulse Oximetry Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76
14.5 Blood Pressure Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76
14.6 Motor Control with Freescale Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77
Hospital Admission Machine ................................................78
15.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78
15.2 Hospital Admission Machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78
15.3 Patient Height and Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80
15.4 Patient Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80
15.5 Communication Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .81
15.6 Backlight Inverter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82
15.7 Multimedia Applications with i.MX53 Family . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83
Digital Stethoscope .........................................................84
16.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .84
16.2 Ultrasonic Probe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85
16.3 Electrical Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85
16.4 Signal Conditioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
16.5 LCD Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86
16.6 Fetal Heart Rate Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .88
Powered Patient Bed .......................................................89
17.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
17.2 Using Motors for Patient Positioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90
17.3 Integrated Real-Time Patient Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90
17.4 Integrated Tilt Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
17.5 Integrated Intercom Using VoIP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91
Freescale Technologies for Diagnostics and Therapy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .92
Medical Imaging
18.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94
18.2 Ultrasound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95
18.3 How Ultrasound Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
18.4 Transducer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
18.5 Multiplexer for Tx/Rx Transducers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95
18.6 Instrumentation Amplifier and Variable Gain Amplifier . . . . . . . . . . . . . . . . . . . . . . . . .96
18.7 Beamformer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96
18.8 Ultrasound Software Library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96
18.9 Microprocessors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97
18.10 Digital X-Ray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100
18.11 Analog Front End . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100
18.12 Photo Detector Grid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100
18.13 Signal Processors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100
18.14 Capacitive Sensing and Touch Screen Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Freescale Technologies for Medical Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .102
Summary ............................................................103
Application Notes . ...............................................104
Appendix ...........................................................105
Digital Signal Processing Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .105
Digital Filter Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .106
Signal Reconstruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .106
Freescale Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .107
Instrumentation Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .107
Analog Measurement Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108
Filter Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .109
Table of Contents

Greetings
Welcome to the latest edition of the Medical Applications User Guide, created to help you
enable the development of breakthrough medical products .
This edition includes some of our newest technologies, like Vybrid controller solutions, i .MX6
application processors, and Bluetooth ® 4 .0 wireless solutions . These technologies play an
important role in several health care applications . Vybrid single- and dual-core devices offer
a mix of processing options for rich user interface and display to safety- and security-centric
solutions . The ARM ® Cortex-A5 core can be leveraged for UI and application, whereas the
ARM ® Cortex-M4TM core can be used for control and compute functions . Our i .MX6 application
processors are the next breed of our popular ARM ® Cortex-A9 core processors offering
single-, dual- and quad-core solutions with HD video, encoding and decoding, as well as 3D
graphics . Bluetooth 4 .0 and Bluetooth low energy will be the kings of ubiquitous connectivity,
and Freescale intends to be front and center with leading edge solution sets .
As a trusted provider of MCUs, MPUs, analog and sensor components, RF amplifiers and
wireless technology, Freescale meets the unique needs of medical designs . These vital
technologies, along with our enablement tools, expertise and alliances, help customers to
develop breakthrough medical systems and life-critical applications . Freescale also offers a
formal product longevity program for the medical segment, ensuring that a broad range of
program devices will be available for a minimum of 15 years1 .
Thanks for considering Freescale to support you in your next medical design . We are dedicated
to supporting your needs and the needs of your customer base and are proud to offer you the
support you deserve . We are confident you will find significant value in working with us today
and in the decades to come . We truly value your business .
Best regards,
Steven Dean
Global Health Care
Segment Lead
Freescale Semiconductor
4
1 See freescale.com/productlongevity for details, terms and conditions
and to obtain a list of products included in the program.
Medical Applications User Guide

Introduction
1.1
Freescale Offers Technology for Life
According to the World Health Organization there are over one billion overweight adults, 860
million chronic disease patients and over 600 million elders age 60 or older1 . Combine that with a
study from the U .S . Centers for Disease Control (CDC) showing modern medical breakthroughs
have raised the average global life expectancy in developed nations to over 75 years2 . With a
large percentage of the total healthcare spend addressing chronic disease, the issue of runaway
healthcare costs and the need to abate them has never been more significant . Proactive and
preventative approaches to healthcare are required .
Semiconductor technology will continue to play a critical role in the development of new technologies
that assist with patient monitoring, diagnostics, therapy and imaging . Freescale is focused on what
we can do as a semiconductor company to not only help extend life, but to promote a better quality
of life . By designing products with the highest safety and reliability standards, healthcare devices using
Freescale technologies work when it counts . Helping to extend life, improve the quality of life, and
providing technologies that enable proactive health and wellness monitoring, Freescale’s technologies
are powering future healthcare devices to benefit everyone who is in contact with this technology . This
is what we mean when we say, “Freescale offers technology for life .”
These market factors along with advancements in semiconductor technologies provide the potential for
transforming the care that we all receive . Medical imaging technology commonly found in radiology or
imaging centers, can now be found in the field—ambulatory or combat situations . Clinical equipment
formerly relegated to the hospital or doctor’s office is now moving into the home . Portable medical
equipment such as blood pressure monitors, blood glucose meters, and weight scales are now
connecting to data aggregators or hubs and transmit your personal health data to the medical cloud
where it is stored in a secure place . All types of healthcare equipment are being pushed from their roots
in clinics or hospitals and into the home .
Developers of medical devices face several challenges . The need to balance processing
requirements with power consumption, the need to provide a faster time to market, and the need
to navigate the regulatory environment are common to all healthcare applications . Freescale designs
a range of embedded products and applicable reference designs so that developers can choose
MCUs, MPUs, analog, sensors, and wireless solutions to meet the requirements of their designs .
Introduction
freescale .com/medical
1 World Health Organization who.int/research/en/
2 CDC, U.S National Center for Health Statistics
5

Introduction
1.2
Welcome to Freescale Medical Solutions
Freescale has focused on solving some of the world’s most important technology challenges for over
50 years . Whether the question has been how cell phones can connect people across the world or
how to harmonize all of the safety features in a car, Freescale MCUs have been part of the solution .
At Freescale we bring that same drive and innovation to the medical industry . The convergence of
an aging population and breakthrough technological advances has created endless opportunities
for automated medical devices . These devices help ensure the future health of millions of people
by providing advances in home health care, clinical activities and medical imaging . Regardless of
the end use, developers of medical devices face similar problems . The need to balance processing
requirements with power consumption helps to ensure a fast time to market . Navigating the regulatory
environment is common with all medical applications . Freescale has implemented a review process
which supports life critical applications .
At Freescale we offer a wide range of products so that developers can choose MCUs, MPUs, analog
and sensor components or RF amplifiers to meet the unique needs of their designs . Developers of
medical technology face many challenges today . Freescale believes that having the right silicon should
not be one of them . We drive innovations that power next-generation healthcare and medical systems
and applications . Our breakthrough thinking, engineering expertise, Medical Center of Excellence,
Medical Advisory Board, Product Longevity Program and active membership in the Continua ® Health
Alliance demonstrate our commitment to health care .
1.3
Why Freescale?
Ecosystems
Providing value beyond the responsibility of providing key semiconductor components is paramount .
Freescale realizes the need to provide our customers a running start on their next medical design,
which is why we embrace one of the strongest ecosystems in the world .
Freescale provides the highly trusted MQX operating system free-of-charge to our customers .
In addition, our partners on the operating systems side include, but are not limited to QNX
Software Systems, Green Hills Software, Mentor Graphics, Wind River, and Windows Embedded .
Development tool support is provided by Keil, Micrium, IAR Systems, Windows Embedded, and
Linux Systems . Alliance partners also include system developers such as Digi International, our
commercialization partner of the Home Health Hub (HHH) reference platform .
Cactus Semiconductor
Freescale and Cactus Semiconductor, a medical application-specific integrated circuit (ASIC)
company, are collaborating to provide customized analog mixed-signal and system-on-chip (SoC)
solutions to the medical market . With more than 30 years of combined experience in the medical
device market, Freescale and Cactus are focused on providing new generations of smaller, lighter,
inexpensive and more efficient medical products that are designed to help improve the quality of life
for millions of people . Freescale and Cactus will initially focus on solutions for implantable medical
devices, blood glucose monitors and other portable medical applications, such as blood pressure
monitors, electrocardiographs and pulse oximetry devices .
6 Medical Applications User Guide

Monebo Kenetic
ECG Algorithms
Freescale and Monebo Technologies are partnering to offer an ECG-on-a-chip solution that allows
customers to choose from more than 300 Freescale MCUs and pair them with the Monebo Kinetic
family of ECG algorithms .
• Highly accurate Kinetic family of ECG algorithms provide interval measurements, beat
classification and rhythm interpretation
• Efficient code is ideal for use in embedded applications
• Designed to optimize battery life (no “warm-up” period)
• FDA 510(k) cleared software allows customers to streamline their regulatory filing
• Lowers development cost by providing a tested and validated solution
• Scalable solutions based on customer requirements
• Optimal design based on the application
• Available on the portfolio of products: Kinetis, Coldfire, Power Architecture ® , i .MX S08, and digital
signal controllers
Medical Specific Reference Designs
Freescale understands that reducing time spent on research and development and speeding time
to market are key concerns of medical device designers . That is why we strive to produce highimpact
design guides in the form of reference designs and application notes . Reference designs give
designers access to component configurations that have been proven to work . Application notes
prepared by knowledgeable medical doctors and Freescale engineers take the guesswork out of
project troubleshooting . Together, these documents offer developers a great jump-start for producing
novel designs based on proven concepts .
For a full list of Freescale medical reference designs and application notes, visit
freescale.com/medical .
Development Tools and Software. Learn Once, Use Everywhere.
Freescale offers a wide variety of hardware development tools to meet the needs of the medical
device designer . Most products feature a cost-effective demo platform for initial evaluation and a
full featured evaluation board for advanced development . These products come packaged with
CodeWarrior IDE, Freescale developed board support package (BSP), complete documentation,
product specific application notes and all the necessary device drivers—everything a designer
needs to get started .
Introduction
freescale .com/medical 7

Introduction
CodeWarrior Development Studio
CodeWarrior Development Studio is a comprehensive integrated development environment (IDE)
that provides a highly visual and automated framework to accelerate the development of the most
complex embedded applications . CodeWarrior’s single development environment is consistent
across all supported workstations and personal computers within an organization, with usage
and features that remain identical across the supported platforms . There is no need to worry
about host-to-host incompatibilities . From text editors to compilers and debuggers, CodeWarrior
Development Studio provides everything the professional embedded developer needs .
Processor Expert Software
Processor Expert Software, a rapid application design tool integrated into the CodeWarrior tool set,
makes migrating between Freescale MCUs a breeze . Just define the functionality you need for your
application and Processor Expert Software generates tested, optimized C-code . When you change
the MCU with the MCU Change Wizard, Processor Expert maps the software and peripheral
components that describe your applications functionality to the resources available on the new
MCU . All you have to do is resolve any resource issues flagged by Processor Expert Software and
you’re finished .
Multimedia Alliance Network
The Multimedia Alliance Network is a global program designed to provide developers with
software tools, such as IDEs, compilers, debuggers and performance analysis tools, from a
comprehensive network of industry leading partners that support the i .MX ARM-based family
of processors . Our rich ecosystem has the essential tools developers need to help speed their
design projects through to market adoption .
Leadership and Longevity
Through leadership in the Continua Health Alliance, Freescale helps to set standards for the
industry . Freescale retains a medical doctor on staff and has a Medical Center of Excellence to
develop new technologies .
The product longevity program provides a minimum 15 years of assured supply for devices for
medical applications . (For terms and conditions and to obtain a list of available products please
see: freescale.com/productlongevity .) With an internal review defined in a standard operating
procedure (SOP), Freescale supports FDA class III or life critical applications in the U .S . and
globally . Quality, reliability, supply assurance, and company and product longevity are key to
understanding the needs of the healthcare market .
From portable medical solutions, to diagnostic, patient monitoring, and therapy systems,
Freescale provides ultra-low-power mixed signal MCUs, high-performance analog, as well as
wired and wireless connectivity that help solve true clinical problems . Freescale offers not only
one of the strongest portfolios of semiconductor products, but also custom IC development
in support of this segment . Additionally, Freescale offers a robust portfolio of medical-centric
reference designs and application notes that help customers go to market faster . Freescale is
much more than a semiconductor company . By offering several application specific reference
designs that include schematics, layouts (Gerber files), and example application code and user
interface software, customers can get up and running with their applications much more quickly .
Vital technology, expertise and leadership make Freescale the trusted provider of high-quality
technical solutions that enable the development of breakthrough medical systems from health and
wellness to life-critical applications .
8 Medical Applications User Guide

Home Portable Medical
2.1
Introduction
The home portable medical market is one of the fastest growing
market segments in the medical device industry. Portable home
medical devices share the need for long battery life, robust data
processing and a wired or wireless communication interface.
Freescale’s MCUs offer the perfect mix of high processing
capabilities, low-power consumption, and analog content. For this
sub-segment, the 8-bit S08 JE/JM and LH/LL cores are well suited
for designs where cost is a key concern. For greater performance,
our Kinetis family of ARM Cortex-M4 MCUs are empowering analog
intensive designs, such as blood glucose meters. Furthermore, as a
pioneer in the communications market, Freescale offers solutions f
or wired and wireless interfaces, including USB, IEEE ® 802.15.4,
Sub-Gigahertz, and ZigBee ® technology.
Freescale micro-electromechanical system (MEMS)-based
pressure and acceleration sensors can be used to acquire physical
parameters. User interfaces embedded with touch sensors enable
medical-friendly buttons and touch screens that can be sanitized
quickly and easily.
Lastly, Freescale offers a focused, integrated analog portfolio that
enables maximum battery life via power management integrated
circuits (PMICs) and allows precise and accurate conversion of
natural, continuous signals to digital signals that MPUs can process.
Medical customers can also benefit from specific custom solutions
that leverage Freescale’s core competencies in precision analog,
mixed signal and power management technologies.
freescale.com/medical 9

Telehealth Systems
3.1
Introduction
One of the trends in the home medical market is the need to monitor
patients away from a hospital or doctor’s office3 . Companies are now
developing solutions that monitor a patient’s vital signs at home and
relay this information to the health care provider.
Physicians or home health care companies give patients a
telemonitoring hub device to use at home. This telemonitoring hub
connects home portable devices used to measure vital signs such as
blood pressure, heart rate, body temperature and other measurements
depending on their needs. This information is then sent to the hub via
USB, Bluetooth wireless technology or ZigBee technology. The hub
then relays the patient’s vital sign information to his or her physician at
periodic intervals (usually once a day) via Ethernet, Wi-Fi ® , phone line
or cellular network.
As telemonitoring is in its infancy, there continue to be new
approaches to address this medical application. Although solutions
vary widely, most of them share similar features and the end result is
the same. Data from the patient is monitored and transferred to the
health care provider.
Form factors for a telehealth system may vary from a simple patient
monitoring system to a high-end robotic telehealth surgical assistant.
The parts of a basic telehealth system are shown in Figure 3-3.
10 3 who .int/medical_devices/en/
Medical Applications User Guide

3.2
Home Health Hub (HHH)
Reference Platform
The Freescale HHH reference platform aids
medical equipment manufacturers in quickly
and easily creating remote-access devices
that can collect, connect and securely
share health data for improved healthcare
management.
The changing dynamics of the aging global
population are creating an increased demand
for new technologies and tools that can offer
peace of mind to the family members of
seniors living at home. There’s also a need to
provide access to healthcare in remote and
growing regions of the world to improve the
quality of life for millions of people. The HHH
reference platform is designed to simplify
development of connected medical devices
and help our customers more easily address
these growing needs.
The HHH reference platform consists of an
aggregator/gateway board based on the lowpower
i.MX28 applications processor (built
on the ARM9 processor) running various
connectivity interfaces to healthcare end
devices and wireless or wired connectivity
for a remote user interface. Also included is
a panic alarm sensor based on Freescale’s
MC12311 sub-1 GHz radio, providing
personal emergency response system (PERS)
functionality. To complete the reference
platform, software such as board support
packages (Linux ® and Windows ® Embedded
Compact 7) and example code are included.
The HHH reference platform comes complete
with the iDigi Telehealth Application Kit,
and is available for purchase through Digi
International at digi.com/hhh.
Freescale’s HHH reference platform, adhering
to Continua device profiles, provides
comprehensive functionality and can be used
as the foundation for connected medical
product designs, giving developers a headstart
to help them get to market faster. The
Freescale HHH reference platform delivers a
hardware implementation and the necessary
Figure 3-1: HHH Reference Platform
Figure 3-2: HHH Platform Demonstration
Home Health Hub Reference Platform Demonstration
TELEHEALTH
868 MHz RF
HHH Panic Alarm
MC12311
i.MX53 Tablet
with Medical
User Interface
Data Aggregator
Based on the
QorIQ P1022RDK
Bluetooth
Nonin Pulse Ox
MC9S08GP32
®
HDP
Bluetooth
SPP
Blood Glucose
Meter
Bluetooth
Low Energy
Thermometer
Freescale Technology Wired Connection
Wireless Connection
software components to provide prevalidated,
secure connectivity for healthcare
devices and user interfaces. The platform
also enables connection to the Microsoft
HealthVault, a privacy- and security-enhanced
online data repository that lets users organize,
store and share their health information.
The HHH reference platform was the Ultimate
Products winner in the 2012 UBM Electronics
Home Portable Medical
Blood Pressure
Monitor
HOME AUTOMATION
freescale .com/medical 11
Ethernet
Health
Care
USB
PHDC
Weight
Scale
Physician
Monitoring Center,
Loved One’s
Social Network
Expansion
Capabilities
Smart Plugs
Smart Appliances
Safety/Security
Lighting Control
Local Display
ACE (Annual Creativity in Electronics) in the
Development Kits, Reference Designs and
SBCs category.

MCIMX28: i.MX ARM9
Applications Processor
Home Portable Medical
The i.MX28 family of applications processors
is part of Freescale’s ARM9 product portfolio.
The i.MX28 family integrates display, power
management and connectivity features
unmatched in ARM9-based devices, reducing
system cost and complexity for cost-sensitive
applications. The LCD controller with touch
screen capability makes it possible to
design creative and intuitive user interfaces
required by many applications. The i.MX28
family reaches new levels of integration in
ARM9 devices and provides the enablement
needed to help design differentiated medical,
industrial, automotive and consumer products
in less time.
Key Features
• 454 MHz ARM926EJ-S core
• 16 KB/32 KB I and D cache
• Power Management Unit (PMU) to power
the device and drive external components
supports Li-Ion batteries and direct
connection to 5-volt supplies
• Dual IEEE ® 1588 10/100 Ethernet with RMII
support and L2 switch (i.MX287)
• Single IEEE 1588 10/100 Ethernet with
RMII or GMII support (i.MX280, i.MX283,
i.MX286)
• Dual CAN interfaces (i.MX286, i.MX287)
• NAND support: SLC/MLC and eMMC 4.4
(managed NAND)
• Hardware BCH (up to 20-bit correction)
• 200 MHz 16-bit DDR2, LV-DDR2, mDDR
external memory support
• Dual high-speed USB with PHY
• Up to eight general-purpose 12-bit ADC
channels
• Temperature sensor for thermal protection
• Multiple connectivity ports (UARTs,
SSP,SDIO, SPI, I2C, I2S)
• Product family supports various feature sets
based on above feature list
Figure 3-3 : i.MX28 Family Block Diagram
i.MX28 Family
Connectivity Advanced Connectivity
I2C x 2
10/100 Ethernet
IEEE ® SPI x 4
1588 x 2
L2 Switch
UART x 6
GPIO
MMC+/SD x 4
Analog
12-bit ADC x 8
2 MSPS ADC x 1
Thermal
Protection
Power
Management
DC/DC 4.2V
LDO x4
Battery Charger
I2 Audio
S x 2
S/PDIF Tx
Figure 3-4: Basic Telehealth Gateway
Telehealth Gateway
Power
Management
Voltage
Regulation
Keypad
MCU/MPU
Freescale Technology Optional
CAN x 2 HS USB PHY x 2
i.MX28
ARM926EJ-S 454 MHz
16K I-Cache 32K D-Cache
Security
HAB4 OTP AES Key
128-bit AES SHA-2 Hashing
Standard System
Timer x 4 PWM x 8
Watch Dog DMA
System Debug
ETM JTAG
USB
and/or
Ethernet
Wireless
Comm
IR Interface
PC/Broadband or
POTS Connection
12 Medical Applications User Guide
PWM
Ext Memory I/F
NAND
BCH 20-bit
DDR2
mDDR
LV-DDR2
Internal
Memory
128 KB SRAM
128 KB ROM
User I/F
LCD Controller
Touch Screen
Scaling
Alpha Blending
Rotation
Color Space
Conversion
Display

3.3
Power Management
Every design needs a power source. If the
power source is not stable, the system may
fail while processing information. If the power
source is not regulated, the system may get
damaged. These failures might cause risks
to the patient. Therefore, the design and
implementation of a stable and regulated
power management system must be carefully
considered to mitigate these risks. Freescale’s
MC34712, MC34713, MC34716 and MC34717
are highly integrated, space-efficient, costeffective
dual and single synchronous buck
switching regulators for multiple applications.
A typical application for these devices is
shown in Figure 3-5.
Key Features
• Integrated N-channel power MOSFETs input
voltage operating range from 3.0V to 6.0V
• 1% accurate output voltage, ranging from
0.7V to 3.6V
• Voltage tracking capability in different
configurations
• Programmable switching frequency range
from 200 kHz to 1.0 MHz with a default of
1.0 MHz
• Programmable soft start timing
• Overcurrent limit and short-circuit
protection
• Thermal shutdown
• Output overvoltage and undervoltage
detection
• Active low-power, good output signal
• Active low shutdown input
The use of these regulators allows the use
of multiple power sources such as batteries,
chargers or AC adapters.
Home Portable Medical
Figure 3-5: 3-2: MC34713 Simplified Application Diagram Diagram
V IN
(3.0V–6.0V)
V MASTER
freescale .com/medical 13
VIN
VREFIN
PGND
VDDI
FREQ
ILIM
GND
MC34713
PVIN
BOOT
SW
INV
COMP
VOUT
Figure 3-6: Block Diagram Using Power Regulators
Figure 3-3: Block Diagram Using Power Regulators
Battery Charger
Battery
+
-
PG
SD
V IN
AC Adapter Other Blocks
MC34713
AC Line
Figure 3-7: Linear Voltage Regulator
Figure 3-4: Lineal Voltage Regulator
Regulated Power Source
Other Blocks
+ E S
+
T
Vin
1uF 0.1uF
Vout
V OUT
MCU
DSP,
FPGA,
ASIC
MCU

Home Portable Medical
3.4
Voltage Regulation
In systems where an MCU or DSP are used,
the power source must be able to provide
the complete range of voltage values to be
applied to multiple VCC pins.
This regulation can be implemented using the
Freescale MPC18730 power management
device. This device regulates five independent
output voltages from either a single Li-ion cell
(2.7V to 4.2V input range), a single-cell Ni-MH
or dry cell (0.9V to 2.2V input range).
MPC18730
The MPC18730 is a 1.15 V/2.4 V 2-ch.
DC-to-DC converter with three low-dropout
regulators.
Key Features
• Operates from single-cell Li-ion, Ni-MH or
alkaline battery
• Two DC-DC converters
• Three low-dropout regulators
• Serial interface sets output voltages
• Four wake inputs
• Low current standby mode
Regulation can also be implemented using the
Freescale MC34704, a multi-channel power
management IC (PMIC) used to address power
management needs for various multimedia
application MPUs such as Freescale’s ARM ®
core-based i.MX applications processor family.
Its ability to provide either five or eight
independent output voltages with a single input
power supply (2.7V and 5.5V), together with
its high efficiency, makes it ideal for portable
devices powered by Li-ion and polymer
batteries or for USB powered devices.
Figure 3-8: Single Synchronous Buck Switching Regulator
Figure 3-5: Single Synchronous Buck Switching Regulator
MCU
VO
VO
2.7 to 4.2V
input VB
14 Medical Applications User Guide
VB
VREF
RSTO1B
EXT_G_ON
RSTO2B
CONTROL
LOGIC
INPUTS
GND
PGND
MC34713
Figure 3-9: MC34704 Block Diagram
MC34704 Figure 3-6: Functional MC34704 Internal Block Diagram Block Diagram
VCC1
VO1
SW1
VCC2
VO2
SW2
SREGI1
SREGO1
SREGI2
SREGO2
SREGI3
SREGO3
Internal Bias Circuit
VREF Generator VDDI Reference
Gate Driver Voltage VG
Fault Detection and Protection
Overvoltage Undervoltage
VREF Generator Short Circuit
Overcurrent
Logic and Control
Startup Sequencing Soft-Start Control
VREF Generator Fault Register
I 2 C Communication and Registers
VG
SWG
A
B
C
D
E
VB
Output Groups
Regulator 1*
Regulator 2
Regulator 3
Regulator 4
Regulator 5*
Regulator 6*
Regulator 7*
Regulator 8
Regulator 5
Programmable
1.613V to 3.2V
Programmable
0.805V to 1.5V
Programmable
0.865V to 2.8V
Programmable
0.011V to 2.8V
Programmable
2.08V to 2.8V
*34704A 8-channel only

MC34704
The MC34704 is a multi-channel PMIC.
Key Features
• Eight DC/DC (34704A) or five DC/DC
(34704B) switching regulators with up to
±2% output voltage accuracy
• Dynamic voltage scaling on all regulators
• Selectable voltage mode control or current
mode control on REG8
• I2C programmability
• Output under-voltage and over-voltage
detection for each regulator
• Overcurrent limit detection and short-circuit
protection for each regulator
• Thermal limit detection for each regulator
(except REG7)
• Integrated compensation for REG1, REG3,
REG6 and REG8
• 5 µA maximum shutdown current
(all regulators are off, 5.5V VIN)
• True cutoff on all boost and buck-boost
regulators
3.5
Keypad
A touch-sensing keypad can be implemented.
This technology has advantages over classic
button-based technology, including:
• Cost effectiveness
• Smaller design
• More durability because there is virtually
no mechanical wear
• Easy to keep clean
Freescale provides software libraries that
implement touch-sensing algorithms using a
MCU’s general-purpose pins. The software
allows the MCU to drive up to 64 touch
pads. It needs only one pull-up resistor per
electrode and timer to complete the circuit.
Freescale’s MPR031, MPR032, MPR083
and MPR084 can also provide a costeffective
solution in a single-chip capacitive
touch-sensing controller. These devices can
be connected to an MCU through an I2C interface.
Home Portable Medical
Figure 3-7: 3-10: Keypad Keypad Implementation Implementation Using Using Proximity Touch-Sensing Software Software
Figure 3-8: 3-11: Keypad Keypad Implementation Using Using Capacitive Capacitive Touch-Sensing Controllers Controllers
MCU
SDA
SCL
MPRO84
MPRO83
Pull-Up
Resistor
MCU with
Touch-Sensing Software
Pull-up
resistor
freescale .com/medical 15
VDD
Up to
64
GPIO Port
GPIO
port
Pull-up
resistor
VDD
8
MPRO31
MPRO32
I2C bus
VDD
8
75K
Touch Pads
7
3
8
6
8 Touch Pads
8 Position Rotary
1
5
3 Touch Pads
2
4
3

MPR084
Home Portable Medical
The MPR084 is an eight-pad touch sensor
controller.
Key Features
• Current touch pad position is available on
demand for polling-based systems
• Rejects unwanted multi-key detections
from EMI events such as PA bursts or user
handling
• Ongoing pad analysis and detection is not
reset by EMI events
• System can set interrupt behavior
immediately after event, or program
a minimum time between successive
interrupts
• Sounder output can be enabled to
generate a key-click sound when the rotary
is touched
• Two hardware-selectable I2C addresses
allow two devices on a single I2C bus
MPR083
The MPR083 is a capacitive touch sensor
controller, optimized to manage an 8-position
rotary shaped capacitive array.
Key Features
• Variable low-power mode response time
(32 ms–4s)
• Rejects unwanted multi-key detections
from EMI events such as PA bursts or user
handling
• Ongoing pad analysis and detection is not
reset by EMI events
• Data is buffered in a FIFO for shortest
access time
• IRQ output advises when FIFO has data
• System can set interrupt behavior as
immediate after event, or program a
minimum time between successive
interrupts
• Current rotary position is always available
on demand for polling-based systems
• Sounder output can be enabled to generate
key-click sound when the rotary is touched
• Two hardware-selectable I2C addresses
allowing two devices on a single I2C bus
Figure 3-9: 3-12: Components Components of a Touch of a Touch-Sensing Sensing System System
E1
E2
En
Buzzer
Capacitance
to Digital
Converter
Feedback to
User
Signal
Processing
Stage
Figure 3-13: Timer Operation to Generate PWM Signal
Figure 3-10: Timer Operation to Generate PWM Signal
TPMxCHn
Overflow
3.6
Touch-Sensing
Software Suite
Period
Pulse
Width
Output
Compare
The touch-sensing software suite (TSS) is a
downloadable software package that enables
a Freescale 8-bit MCU as a touch sensor. This
provides cost-effective and flexible solutions
for human-machine interfaces. TSS is a
modular and layered software that enhances
forward compatibility and simplifies touch key
configurations. It also enables the integration
of connectivity, LCD, LED, audio and other
peripherals.
Key Features
• Intellectual property (IP) ownership
in hardware layouts and software
implementations such as capacitance
conversion, key detection and decoding
algorithms
• Modular software design to add new
algorithms
Overflow Overflow
Output
Compare
16 Medical Applications User Guide
Output
Output
Compare
• Easy to use with the simple and robust
API set, including algorithms, patents
and system implementations that protect
customer applications from noisy/not ideal
environments
• Capability to coexist with customer
application code
• Available application layer software, decoders
(rotary, slider, keypads), demonstrations and
reference designs to expedite customer time
to market
• Possible to use different materials such as
electrodes, PCB, Flex PCB, membranes,
glasses and foams

3.7
How it Works
The external capacitance is charged and
discharged continuously. This depends on
the sample configuration. At the time the
capacitance is being charged the timer is
running and counting. When the electrode
voltage reaches 0.7 VDD, the timer stops
and the counter value is taken. The external
capacitance is modified at the touch
event, modifying the time charge. When
the electrode is touched, the capacitance
increases. Therefore the count is higher. The
number of samples taken is user-configurable
and determines how many times the
capacitance is charged and discharged when
the scanning starts. A touch sensing system
contains the following components:
• Electrodes: Physical area that the user uses
as the interface. Usually made of PCB or
indium tin oxide (ITO)
• Capacitance to digital converter: Measures
capacitance on each electrode and
produces a digital value as output
• Signal processing stage: This stage
translates measured capacitance to touch
status and then to a logic behavior (rotary,
keypad, slider and so on)
• Output: Indicates touch detection both to
the user and the application
3.8
Freescale Touch
Sensor Summary
• Extra hardware (except for pull-up resistors)
is not necessary with Freescale TSS. The
host’s TSS code is required to process and
perform more. Each touch pad must be
connected to one GPIO on the MCU.
• This is a two-chip solution. Because of
the I2C interface, capacitive touch-sensing
controllers allow the number of electrodes to
be expanded by using two pins of the MCU.
• MPR083 and MPR084 can drive up to eight
electrodes each. Each electrode needs a
pull-up resistor.
• MPR031 and MPR032 are ultra-small
touch-sensing controllers that support up
to three electrodes. They need one external
Figure 3-11: 3-14: Variations in in Period and and Pulse Pulse Width Width
Period
Pulse
Width
Figure
Figure
3-12:
3-15: Implementation
Implementation
Example
Example
component and do not need pull-up
resistors in the electrodes.
Information about touch-sensing technology and
the application note titled 3-Phase AC Motor
Control with V/Hz Speed Closed Loop Using the
56F800/E (document AN1958), which provides
information about touch panel applications, can
be found at freescale.com.
3.9
PWM Function for a
Speaker Circuit
Pulse width modulation (PWM) can be
implemented using a simple timer (in output
compare mode) typically integrated in one
of Freescale’s 8-bit MCUs. The pulse width
variations determine the volume of the sound
(energy average per cycle). The timer has a
register for the output compare function to vary
the pulse width, and therefore the volume.
Home Portable Medical
Same Duty Cycle, Different Frequency
To vary the tone of the sound, the signal
period must be changed. To change
the period, the timer has a register that
determines the number of counts until the
timer overflows.
Figure 3-14 shows on the left side, the
signal changing the pulse width but with a
determined period. On the right side, the
signal period is halved, but the percentage of
the pulse is the same as the signals on the left
side. This is the principle that can be used to
vary the tone and volume of the sound.
Figure 3-15 shows a basic implementation of
the circuit to generate an audio signal. The
value of R is determined by the transistor
B
used to amplify the signal generated by the
MCU, and by the voltage level of the
MCU output.
freescale .com/medical 17
MCU
Toner Output
Compare / PWM
RB
Speaker
VDD
RC
Q1

Home Portable Medical
3.10
Wireless Communication
Offering a broad portfolio of RF products,
Freescale primarily serves the wireless
infrastructure, wireless subscriber, generalpurpose
amplifier, broadcast and industrial
markets. Freescale pioneered RF technology
and continues to be a leader in the field
by providing the quality, reliability and
consistency that is associated with our
RF products.
3.11
Introduction to ZigBee
Technology
The ZigBee Alliance defines low-power
wireless communication protocol stacks and
profiles designed for monitoring and control of
devices in a variety of markets and applications.
These include consumer, smart energy, control
and automation and medical markets. There are
two different specifications (ZigBee and ZigBee
Consumer) as well as multiple profiles that focus
on specific markets. Freescale provides the
necessary building blocks used for both ZigBee
and ZigBee Consumer solutions, including
hardware, software, tools and reference designs.
3.12
Freescale Solutions with
ZigBee Technology
The ZigBee protocol stack is designed for
monitoring and control applications such
as building automation and smart energy. It
features self-forming and self-healing mesh
networks that help differentiate it from
other technologies.
Figure 3-16: MC1319x Family Block Diagram
Figure 3-13: MC1319x Family Block Diagram
Transceiver
3.13
Configuration Diagrams
for Freescale ZigBee
Transceiver Families
See diagrams from Figure 3-16 to 3-19.
MC1319x
Impedance
Coupling
Figure 3-17: MC1320x Family Block Diagram
Figure 3-14: MC1320x Family Block Diagram
MC1320x
Transceiver
Switch
3.14
ZigBee Health Care
Profile and IEEE 802.15.4
For medical care providers, access to timely
and accurate information improves the ability
to provide the highest quality of patient care.
Decision support is not limited to just the
bedside. The quality of care often depends
on the ability to share vital patient data with
clinicians in real time outside the care facility.
This means clinicians can provide immediate
feedback to attending physicians based on
real-life clinical research as well as track
treatment paths, and give results beyond the
Impedance
Coupling
walls of the hospital over the patient’s lifetime
to improve future treatment methodologies.
ZigBee technology is rapidly proving to
be useful in these applications. It can help
provide greater freedom of movement for
the patient without compromising automated
monitoring functions. ZigBee technology
can be deployed in a number of products
that can help ensure better patient care and
more effective care tracking by providing
cost-effective, low-power wireless technology
that can cover large buildings and institutions
with mesh networking.
Freescale has received ZigBee Certified
product status for its ZigBee Health Care
wireless health and wellness processing
platforms. The ZigBee Certified products
status is awarded to products that have been
tested and met criteria for interoperability
that enable wireless devices to securely and
18 Medical Applications User Guide
Switch

eliably monitor and manage non-critical,
low-acuity health care services.
The Freescale processing platforms awarded
the certification include the MC13202FC
transceiver in combination with the
MC9S08QE128 MCU, and the MC13224V
integrated transceiver with a 32-bit ARM7 MCU. These products are optimized for
sensing and monitoring applications requiring
low-power for battery-operated or batterybacked
systems.
3.15
Why ZigBee is Ideal
for Wireless Vital Sign
Monitoring
A ZigBee network for long-term care consists
of a patient monitoring system and the network
infrastructure to communicate with a central
location or caregiver station as well as other
mobile devices. Wireless monitoring provides
feedback through a gateway to a central server
where data is maintained. This data can be
accessed by doctors, nurses and other health
care professionals between caregiver visits,
alerting them to changing conditions that need
attention. Wireless monitoring also allows
institutions to track care for accountability and
insurance requirements.
3.16
Freescale Enables ZigBee
Health Care Profile for
Medical Devices
Freescale solutions with ZigBee technology
provide the perfect combination of cost
effectiveness, low power, high integration
and high performance required for medical
monitoring applications.
These solutions include not only silicon
but also software, development tools
and reference designs to help simplify
development. Freescale’s BeeStack ZigBeecompliant
stack with BeeKit Wireless Toolkit
provides a simple software environment
Figure 3-18: MC1321x Family Block Diagram
Figure 3-15: MC1321x Family Block Diagram
MC1321x
MCU and
Transceiver
Switch
Impedance
Coupling
Figure
Figure
3-16:
3-19:
MC1322x
MC1322x
Family
Family
Block
Block
Diagram
Diagram
MCU
Transceiver
Module
MC1322x
Impedance
Coupling
Figure
Figure
3-17:
3-20:
ZigBee
Zigbee
Transceiver
Transceiver
Options
Options
IEEE ® 802.15.4
MC1319x
MC1320x
MC1321x
MC1322x
to configure network parameters. This tool
allows customers to use a wizard and dropdown
menus to help configure the ZigBee
network parameters.
To learn more about ZigBee technology,
visit freescale.com/ZigBee.
Home Portable Medical
freescale .com/medical 19
Switch
For information on wireless communication,
power management, keypad and speaker
implementation modules, see the Introduction
to this chapter.

Home Portable Medical
3.17
Transceivers and Receivers
MC13191
The MC13191 is a 2.4 GHz low-power
transceiver.
Key Features
• 16 channels
• 0 dBm (typical), up to 3.6 dBm maximum
output power
• Buffered transmit and receive data packets
for simplified use with cost-effective MCUs
• Supports 250 kbps O-QPSK data in 2.0 MHz
channels and full spread-spectrum encode
• Link quality and energy detect functions
• Three power-down modes for power
conservation (Hibernate, Doze, Tx and Rx)
• Rx sensitivity of -91 dBm (typical) at 1.0%
packet error rate
3.18
Freescale Continua
Health Alliance ® Certified
USB Library Software
One of the most considerable challenges
for medical designers is medical standard
compliances. The Continua Health Alliance
(continuaalliance.org) consists of more than
200 members that have come together to
form work groups to set standards for
medical systems.
Having multi-vendor medical devices
communicating among themselves is not an
easy task. Every day, protocols such as USB
are being implemented in medical devices.
Continua provides guidelines to address
standardization in connectivity.
Figure 3-21 describes a medical device
system topology.
Freescale provides complimentary stacks that
enable the user with ready-to-use software to
begin their path to standardization. Continua
Health Alliance is responsible for certifying
devices for compliance.
Figure 3-21: Continua Ecosystem Topology
Figure 3-18: Continua Ecosystem Topology
PAN Devices
Application Hosting Devices LAN/WAN
Figure 3-22: Medical Applications USB Stack
Figure 3-19: Medical Applications USB Stack
Mouse Medical USBSeries Storage
HID PHD CDC MSD
Device Layer
S08 CF-V1 Controll
S08 CF-V1 Core
Controller
Hardware
Register
20 Medical Applications User Guide
Class
Device

3.19
Standard Medical
USB Communication
For USB communication, two main standards
must be considered:
• IEEE ® 11073, which provides structure to
the communication interface
• Personal health care device class (PHDC),
which is a standard implementation of USB
for medical devices
The advantage of designing medical
applications with a dedicated medical stack
instead of a conventional USB stack is that
a medical USB stack is designed specifically
for medical USB devices. It eases medical
application data exchange because it has a
specific device specialization layer. Designing
medical applications under a conventional
USB stack may not provide the added value
of medical organizations’ certifications.
Three main factors need to be considered
when selecting a particular USB connectivity
software implementation for medical devices.
1. Standardization: The solution is based
on well-known standards in the industry.
This helps to ensure success and proper
introduction of the product to the market.
2. Connectivity: The implementation allows
connecting multiple devices from different
vendors within an ecosystem topology.
A connectivity-friendly environment is
sustained by a robust and easy-to-use
software stack.
3. Portability: Multi-device independent
layered architecture eases porting of code
among devices. Selecting a hardware
vendor with a broad portfolio is key to
ensure customization and product roadmap
establishment.
Software architecture ensures code
robustness, portability and reliability in
embedded systems development.
Figure 3-23: Broadband Block Diagram
Figure 3-20: Broadband Block Diagram
Pedometer
Weight
Scale
Blood-
Pressure
Cuff
Fitness
Equipment
Medication
Tracking
Pulse
Ox
Home Portable Medical
Table 3-1. Freescale MCU/MPU Families that Support the USB Personal Health Care Device
SOC Use Case
S08
MC9S08MM128 PAN device
MC9S08JM16 Low-end PAN device
MC9S08JM60 PAN device
MC9S08JS16
ColdFire V1
Low-end PAN device
MCF51JM128 PAN device, hybrid device, application hosting device
MCF51MM256 PAN device, hybrid device, application hosting device
MCF51JE256 PAN device, hybrid device, application hosting device
MCF51(JF/JU)128
ColdFire V2
PAN device, hybrid device, application hosting device
MCF5225x
ARM
PAN device, hybrid device, application hosting device
® Cortex-M4
Kinetis KL2x, KL4x PAN device, hybrid device, application hosting device
Kinetis MK20, MK40, MK50 and MK60
ARM i.MX
PAN device, hybrid device, application hosting device
MCIMX233 PAN device, application hosting device
MCIMX28x PAN device, application hosting device
MCIMX51x Application hosting device
freescale .com/medical 21
Implant
USB Personal Health Care
Device Class Specification
Digital
Home
Cell Phone
Personal Health
System
PC
Internet
Health Care
Provider
Service
Disease
Management
Service
Personal
Health Record
Service
Implant
Monitoring
Service

Home Portable Medical
The medical applications USB stack provides
Figure 3-24: Medical Connectivity Library (IEEE
the user with a PHDC implementation that Figure 3-21: Medical Connectivity Library (IEEE 11073)
is divided into layers for portability and
simplicity. The stack can also be used as a
Application
general-purpose USB stack. The stack has
been ported to 8-bit 9S08 and 32-bit ColdFire
Device Specialization Interface
and Kinetis devices. The stack can be
downloaded at freescale.com.
Medical Connectivity
® 11073)
The USB protocol can be further broken into
PHDC and low-level driver layers. The lowlevel
driver abstracts USB IP to provide a
generic interface to the class driver.
The PHDC is a function-specific class layer.
Its responsibility is to hide transport-specific
details from the data exchange protocol layer.
Freescale additionally provides a medical
connectivity library that provides users with
standard IEEE 11073 connectivity. This library
is transport-independent because of its
transport independent layer (TIL). Therefore,
protocols that may be used include serial,
Bluetooth, USB and ZigBee. The library can
be downloaded at freescale.com.
USB devices compliant with industry
standards such as IEEE 11073 will be
developed under organizations such as
Continua Health Alliance for future use. A
sample application featuring a weight scale
device has been created to demonstrate the
value of working under the standardization
scheme and allowing multi-vendor device
interoperability. The demo videos are available
at freescale.com.
In the weight scale example, the personal
health care application interacts with the host
computer using IEEE 11073-20601 and IEEE
11073–10415 (weight scale) protocols. It is
important to note that the host computer runs
the same IEEE 11073 protocols. One specific
example of such implementation is covered by
Continua Alliance. Member companies of the
Continua Alliance can obtain CESL reference
software. After installing this software the
host is emulated and ready to connect to the
weight scale device.
USB Ethernet Transport
USB TCP/IP Transport
USB HW Ethernet Transport
Available Functionality
Table 3-2. MPC8313E Processor Highlights
Medical Connectivity
Library
Interface API
TIL Interface
TIL SHIM
Interface API
MPC8313 MPC8313E
Core e300, 2-IU, w/FPU, up to 400 Hz
L1 I/D cache 16 KI/16 KD
Memory controller 16/32-bit DDR2-333
Local bus controller 25-bit/8-bit dedicated or 25-bit/16-bit MUX Add/Data up to 66 MHz
PCI One 32-bit up to 66 MHz wake on PME
Ethernet Two 10/100/1000 MACs, SGMII. 98145.452
98145.452 One High-Speed USB 2.0 host/device + HS PHY, wake on USB
Security None SEC 2.2
UART Dual
I 2 C Dual
SPI 1
Boot options NOR, NAND
Internal controller PIC
MUX/dedicated GPIO 10/16
DMA 4 channels
Estimated core power 1.2W
Power management Standby power

Freescale has developed sample code to
connect with the Continua Alliance emulator.
After flashing an 8-bit 9S08JM device with
this software, the device is recognized as
a Continua USB interface. The supplied
drivers allow the device to be recognized
as a USB personal health care device. The
Continua manager is then launched and
transport communication starts. The weight
measurements are sent from the 9S08JM
device to the host. Other personal health care
applications can also interact with the host
system developed by Continua. These include
IEEE 11073–10407 (blood pressure monitor)
IEEE 11073–10417 (glucose meter) and IEEE
11073–10408 (thermometer) protocols.
MPC8313E: PowerQUICC II
Pro Processor
The MPC8313E is a cost-effective, lowpower,
highly integrated processor. The
MPC8313E extends the PowerQUICC family,
adding higher CPU performance, additional
functionality, and faster interfaces while
addressing the requirements related to time
to marked, price, power consumption and
package size.
S08JS: 8-bit MCU Family
The S08JS 8-bit MCU family features a
full-speed 2.0 USB device controller and
integrates a USB transceiver to help save
cost by eliminating off-chip components.
Key Features
• 48 MHz HCS08 core
• Integrated full-speed USB 2.0 device
controller
• 16/8 KB flash, 512B SRAM, 256B USB
RAM 2.7V to 5.5V operation, -40°C to
+85°C operation
• ROM-based USB bootloader
• SCI, SPI, 8-channel KBI
Figure 3-25: MPC8313E Block Diagram
Figure 3-22: MPC8313E Block Diagram
Security
Acceleration
Core
Accelerators
I/O
2x Gigabit
Ethernet
2-lane SerDes
• 16-bit timers: 1 x 2-channel
• MTIM: 8-bit timer
• One hardware CRC module
• 12 general-purpose I/O and two
output-only pins
• Multiple purpose clock generation
• 24 WFN, 20 SOIC package options
e300 Core
Complex
Coherent System Bus
Home Portable Medical
DDR/DDR2
SDRAM Controller
Local Bus
Performance Monitor,
DUART, I 2 C,
Timers, GPIO,
Interrupt Control
freescale .com/medical 23
SGMII
USB
ULPI PHY
Figure 3-26: JS 16/8 Block Diagram
Figure 3-23: JS 16/8 Block Diagram
MTIM
KBI
ICE+BDM
2-ch., 16-bit
Timer
PCI
4-ch.
DMA
ROM-Based
USB Bootloader
USB 2.0
MCG
256B
USB RAM
6 KB
8 KB
Memory
Options
Flash
512 KB SRAM
Debugging/Interfaces Peripherals Flash RAM Core Plus Features
SPI
SCI COP
RTC CRC
S08 Core

Blood Pressure Monitor
4.1
Introduction
Blood pressure monitors are medical devices for patients who suffer
from hypertension who need to detect, measure and track their blood
pressure. This is one of the vital signs that need to be measured
to make a precise diagnosis. Up to 25 percent of patients who
are diagnosed with hypertension do not suffer from hypertension,
but instead from white-coat hypertension. This is the elevation
of arterial pressure due to anxiety or stress produced by a health
professional while taking a blood pressure test. This is why personal
blood pressure monitors can help in detecting true hypertension as
stipulated in the Joint National Committee and the 2003 guidelines
from the European Society of Hypertension.
Blood pressure monitoring systems use techniques such as
oscillometric methods and Korotkoff measurements. The oscillometric
method consists of measuring the oscillations in pressure inside
the cuff that the patient wears. The Korotkoff method is based on
listening to sounds when taking blood pressure.
Automatic blood pressure monitoring conducted at home is
increasingly used in the diagnosis and management of hypertension.
This includes arm cuff and wrist cuff units. Figure 4-1 illustrates the
system block diagram of a typical blood pressure monitor. This block
diagram and others like it are available at freescale.com/medical.
24 Medical Applications User Guide

4.2
Heartbeat Detection
The heartbeat rate is considered one of the
vital patient measurements. The following
procedure is used to obtain this measurement.
While deflating a cuff that is attached to a
person’s arm, you can see slight variations
in the overall cuff pressure (Figure 4-2). This
variation in the cuff’s pressure is due to the
pressure change from blood circulation. This
variation is amplified through a filter designed
at 1 Hz, and set to an offset. This new signal
is the heartbeat signal.
The signal in Figure 4-3 shows variations in the
pressure signal and is a graphical representation
of a patient’s heartbeat over time.
4.3
Systolic and Diastolic
Measurements
Heartbeat detection is a simple oscillometric
method used to determine systolic blood
pressure (SBP) and diastolic blood pressure
(DBP). The simplified measurement is
based on the idea that the amplitude of the
heartbeat signal changes as the cuff is inflated
over the SBP. While the cuff is deflated, the
amplitude of the heartbeat signal grows as
the cuff pressure passes the systolic pressure
of the patient. As the cuff pressure is further
reduced, the pulsations increase in amplitude
until the pulsations reach a maximum pulse
known as the mean arterial pressure (MAP),
and then reduce rapidly until the diastolic
pressure is reached (Figure 4-4).
4.4
Invasive Blood Pressure
Monitors
The most accurate way to measure blood
pressure is to take the measurement directly
from an arterial line. The advantage of this
method is continuous measurement, versus
a discrete measurement in the non-invasive
method.
Freescale has long been a provider of sensors
for the invasive blood pressure monitoring
segment. Figure 4-6 shows different types of
packaging for Freescale pressure sensors.
Home Portable Medical
Figure 4-1: Blood Pressure Monitor (BPM) General Block Diagram
Blood Pressure Monitor (BPM)
Power
Management
Pressure Sensor
Inertial
Sensor
Amplifier
DC Brush
Motor Control
Pump Motor
Bleed Valve
Freescale Technology Optional
Figure 4-2: Heartbeat Signal
Figure 4-2: Heartbeat Signal
1800
1600
1400
1200
1000
800
600
400
200
Wireless
Comm
Keypad
freescale .com/medical 25
SPI/I 2 C
SPI/I 2 C
Main System
Pressure
MCU
USB
To PC
Display
Non-Volatile
Memory
Sensor System
(Intergrated with main system
for wrist applications or with cuff
for all other applications)
0
1 449 897 1345 1793 2241 2689 3137 3585 4033 4481 4929 5377 5825 6273 6721
Figure 4-3: Heartbeat over Time
Figure 4-3: Heartbeat over Time
2500
2000
1500
1000
500
0
Heartbeat
1 458 915 1372 1829 2286 2743 3200 3657 4114 4571 5028 5485 5942 6399 6856
Pressure
Heartbeat

Home Portable Medical
4.5
Obtaining Pressure
Measurements
The basic function of a blood pressure monitor
is to measure arterial pressure. One method to
obtain this measurement is to use a pressure
sensor that measures the present pressure.
The variations in pressure change the velocity
of a motor that controls an air pump. The air
chamber presses the arm up to the systolic
pressure. When systolic pressure is reached,
the valve can deflate the cuff around the arm
gradually. At the same time, the pressure
sensor takes the measurements. Some useful
areas for Freescale sensors include the
following health care monitoring applications:
• Blood pressure (BP) monitors
• Invasive BP monitors
• Intrauterine BP monitors
• Hospital bed controls
• Respirators
• Sleep apnea monitors
• Sports diagnostic systems
• Dialysis equipment
• Drug delivery for inhalers
• Physical therapy
Freescale pressure sensors are specifically
designed for applications where high quality
and reliability are especially important.
Freescale sensors offer a wide range of functions
and features, from basic to fully amplified and
temperature-compensated devices.
The amplified series can easily be connected
to an MCU. The low-voltage pressure sensor
series is designed to meet power efficiency
demands to extend longevity for simpler, costsensitive
medical and portable electronics.
Freescale pressure sensors combine
advanced micro-machining techniques, thinfilm
metallization and bipolar semiconductor
processing that provides accurate and highly
reliable sensors at competitive prices.
Figure 4-4: Heartbeat Versus Diastolic Pressure
Figure 4-4: Heartbeat Versus Diastolic Pressure
2500
2000
1500
1000
Figure 4-6: Freescale Pressure Sensors
Figure 4-6: Freescale Pressure Sensors
MPAK
MPAK Axial Port
Small
Outline
Package
(SOP)
500
Case
482
Super
Small
Outline
Package
(SSOP)
Case Tire
1317 Pressure Axial Basic
Monitor Port Element
Through
Hole 492B
26 Medical Applications User Guide
SBP
MAP
0
1 458 915 1372 1829 2286 2743 3200 3657 4114 4571 5028 5485 5942 6399 6856
Vacuum
Port
Side
Port
DBP
Dual
Port
Axial
Port
Unibody Medical
Chip Pak
Dual
Port
Through
Hole
Axial Port
Gauge
Port
Through
Hole
Axial Port
Heartbeat
Pressure
Figure 4-5: Flexis MCU Blood Pressure Monitor Reference Design Block Diagram
Figure 4-5: Flexis Microcontroller Blood Pressure Monitor Reference Design Block Diagram
Motor Control
Air Chamber
OLED
Display
Valve
DC Motor
(Air Pump)
Power Stage
USB
Connector
(Type B)
Batteries
SPI (3)
GPIO (3)
TPM (1)
Power Stage
MPXV5050GP
(Pressure
Sensor)
High Pass
Filter
MC9S08JM60
USB MCU
Power Supply
(3.3, 12V)
ADC (1)
MCU
MC9S08QE 128
SCI (2)
ADC (1)
TPM (1)
SPI (4)
Ctrl (2)
GPIO (1)
GPIO
(39)
I 2 C (2)
MC13202
(ZigBee ®
Transceiver)
MPR083
(Capacitive
Touch)
Non-Volatile
Memory
Low Pass
Filter (RC)
Audio
Amplifier
Electrodes (5)
Speaker
Case
423A
PCB
Antenna
Through
Hole
Axial Port

4.6
Blood Pressure Monitor
Reference Design
For more information on how to build a
blood pressure monitor with the Flexis QE
MCU family, download the following PDF
documents from freescale.com:
• Application note AN4328: Blood
Pressure Monitor Fundamentals and
Design. This application note describes
the implementation of a basic blood
pressure monitor using the MK53N512,
MC9S08MM128 or MCF51MM256 medical
oriented MCUs, pressure sensors, as well
as the MED-BPM development board. Code
is provided so development is faster. The
block diagram is shown on Figure 4-8.
• Application note AN3500: Blood Pressure
Monitor Using Flexis QE128 and Pressure
Sensors
• Design reference manual DRM101:
Blood Pressure Monitor Using the Flexis
QE128 Family and Pressure Sensors
Find more information about the components
of a blood pressure sensor in this guide:
• For Inertial Sensor, see Chapter 9, Hearing
Aids Introduction.
• For Wireless Communication, Power
Management, Keypad and Speaker
Implementation modules, see Chapter 3,
Telehealth Systems Introduction.
• For LCD screen connection, see Chapter 6,
Blood Glucose Meter Introduction.
• For Pressure Sensor implementation and
Motor Control devices, see Chapter 12,
Ventilation and Spirometry Introduction.
Figure 4-7: Pressure Gauge Block Diagram
Figure 4-8: Pressure Gauge Block Diagram
Motor Control
Air Chamber
Home Portable Medical
freescale .com/medical 27
Valve
DC Motor
(Air Pump)
Power Stage
Figure 4-8: MED-BPM Block Diagram
Figure 4-9: MED-BPM Block Diagram
GPIO
GPIO Optocoupler
Low-Pass
Filter
Buffer with
Internal OpAmp
Air
Pump
Air
Value
ADC
High-Pass
Filter
TPM (1)
Power Stage
MPXV5050GP
(Pressure
Sensor)
Arm Cuff
High Pass
Filter
Pressure
Sensor
MP3V5050
ADC (1)
ADC (1)
Signal Amplifier
with Internal OpAmp
TPM (1)
SPI (4)
Ctrl (2)
MCU
MC9S08QE 128
Low-Pass
Filter
Freescale Technology MM/KSX Internal Non Electrical Connection
ADC

MCF51QE: Flexis 32-bit
ColdFire V1 MCU
Home Portable Medical
The QE family, comprised of a pin-compatible
8-bit and 32-bit device duo, is the first family
in the Flexis MCU series. The Flexis series
of controllers is the connection point on the
Freescale Controller Continuum, where 8- and
32-bit compatibility becomes reality.
The MCF51QE128 device extends the low end
of the 32-bit ColdFire controller family with
up to 128 KB flash memory and a 24-channel
12-bit analog-to-digital converter (ADC). The
32-bit MCF51QE128 is pin, peripheral and tool
compatible with the 8-bit S08QE128 device.
They share a common set of peripherals and
development tools, delivering the ultimate in
migration flexibility.
Key Features
Figure 4-10: MCF51QE Block Diagram
• 50 MHz ColdFire V1 core, 25 MHz bus speed
• Up to 128 KB flash memory
• Up to 8 KB RAM
• 1.8 to 3.6V operating voltage range
• Loop-control oscillator
• Highly accurate internal clock (ICS)
• Single-wire background debug interface
• Up to 70 GPIO ports, plus 16 bits of
rapid GPIO
• 16 keyboard interrupt pins
• -40°C to +85°C temperature range
• Pin compatibility in 64- and 80-pin
LQFP packages
• Common development tools including
CodeWarrior for MCUs 6.0
Figure 4-9: MCF51QE Block Diagram
8 KB
SRAM
128 KB
Flash
4 KB
SRAM
64 KB
Flash
4 KB
SRAM
32 KB
Flash
Memory
Options
Core Optional
Real-Time
Counter
ColdFire V1
Core
2 Rapid
GPI/O Ports
System
Inegration
28 Medical Applications User Guide
BDM
ICS +
ULP Osc
GPI/O
2 KBI 2 x SPI 2 x I 2 C
24-ch.,
12-bit ADC
COP
K50 Measurement MCUs
The K50 MCU family is pin, peripheral and
software compatible with other Kinetis MCUs
and provides designers with an analog
measurement engine consisting of integrated
operational and transimpedance amplifiers
and high-resolution ADC and DAC modules.
The family also features IEEE 1588 Ethernet
and hardware encryption, full-speed USB
2.0 On-The-Go with device charger detect
capability and a flexible low-power segment
LCD controller with support for up to 320
segments. Devices start from 128 KB of
flash in 64-pin QFN packages extending up
to 512 KB in a 144-pin MAPBGA Package.
6-ch.,
16-bit
Timer
2 x 3-ch.,
16-bit
Timer
2 x SCI
2 x
Comparator
Key Features
Kinetis K50 MCU features
and peripherals in the integrated
measurement engine:
• Ultra-low-power operation
• 2x OPAMP
• 2x TRIAMP
• 2x 12-bit DAC
• 2x 16-bit SAR ADC, up to 31 channels
with programmable gain amplifiers (PGA)
• Programmable Delay Block (PDB)
• I2C • USB connectivity
• ARM Cortex-M4 core with DSP
(Digital Signal Processor) instructions

MCF51MM: Flexis 32-bit
ColdFire V1 MCUs
The MCF51MM256/128 provides ultra-lowpower
operation, USB connectivity, graphic
display support and unparalleled measurement
accuracy, all in a single 32-bit MCU, allowing
designers to create more fully featured
products at lower cost. The
MCF51MM256/128 is ideal for medical
applications or other applications requiring a
significant amount of precision analog such as
instrumentation and industrial control.
The MCF51MM256/128 is part of the
Freescale Flexis MCU series.
Features:
• ColdFire V1 core delivering a 50 MHz core
speed and 25 MHz bus speed
• Up to 256 KB flash and 32 KB SRAM
• Low-power stop 2 current: 500 nA
(32 KB of active SRAM)
• 2 x general purpose opamps
• 2 x transimpedance amplifiers
• 16-bit SAR high resolution analog-to-digital
converter (ADC)
• Analog Comparator with 5-bit digital-toanalog
converter (DAC)
• Internal voltage reference
• USB – device/host/on-the-go controller
• 2 x serial peripheral interface (SPI),
2 x serial communication interface (SCI)
and 1 x I2C • Mini FlexBus (external bus interface EBI)
• Included in Freescale’s Product
Longevity Program
Figure 4-10: Kinetis K50 Family Block Diagram
Figure 4-11: Kinetis K50 Family
Security
and Integrity
Cyclic
Redundancy
Check (CRC)
Random
Number
Generator
Cryptographic
Acceleration
Unit (CAU)
Core
ARM ® Cortex-M4
72/100 MHz
Debug
Interfaces
Interrupt
Controller
Standard Feature
DSP
Analog
16-bit
ADC
PGA
Analog
Comparator
6-bit
DAC
12-bit
DAC
Voltage
Reference
OPAMP
TRIAMP
Home Portable Medical
System Memories
Internal and
External
Watchdogs
Memory
Protection Unit
(MPU)
Xtrinsic
Low-Power
Touch-Sensing
Interface
Segment
LCD Controller
freescale .com/medical 29
DMA
Low-Leakage
Wake-Up Unit
Timers
FlexTimer
Carrier
Modulator
Transmitter
Programmable
Delay Block
Periodic
Interrupt
Timer
Low-Power
Timer
Independent
Real-Time
Clock (IRTC)
IEEE ® 1588
Timer
Optional Feature
Program
Flash
(128 to 512 KB)
FlexMemory
(32 to 256 KB)
(2 to 4 KB EE)
Serial
Programming
Interface
(EZPort)
SRAM
(32 to 128 KB)
External
Bus Interface
(FlexBus)
Clocks
Phase-Locked
Loop
Frequency-
Locked Loop
Low/High-
Frequency
Oscillators
Internal
Reference
Clocks
Communication Interfaces HMI
I 2 C
UART
(ISO 7816)
SPI
IEEE 1588
Ethernet MAC
I 2 S
Secure
Digital Host
Controller
(SDHC)
USB OTG
(LS/FS)
USB Charger
Detect (DCD)
USB Voltage
Regulator
GPIO

S08MM: Flexis
8-bit MCUs
Home Portable Medical
The 9S08MM128/64/32 provides ultra-
low-power operation, USB connectivity,
graphic display support and unparalleled
measurement accuracy, all in a single 8-bit
MCU, allowing device designers to create
more fully featured products at a lower cost. It
is ideal for applications requiring a significant
amount of precision analog.
The 9S08MM128/64/32 is part of Freescale’s
Flexis MCU series.
Features:
• S08 core delivering a 48 MHz core speed
and 24 MHz bus speed
• Up to 128 KB flash and 12 KB SRAM
• Low-power stop 2 current: 450nA
(12 KB of active SRAM)
• 2 x OPAMP- General purpose opamps
• 2 x TRIAMP- Transimpedance amplifiers
• 16-bit SAR analog-to-digital converter
(ADC) – high resolution ADC
• Analog comparator
• Internal voltage reference
• USB device controller
• 2 x serial peripheral interface (SPI),
2 x serial communications interface (SCI)
and 1 x I2C Figure 4-12: 4-11: MCF51MM256 Block Block Diagram Diagram
2x OPAMP
2x TRIAMP
PDB
MCG
Figure 4-12: MC9S08MM128 Block Diagram
Figure 4-13: MC9S08MM128 Block Diagram
2x OPAMP
2x TRIAMP
16-bit SAR ADC I2 12-bit DAC LVI
C
PDB
2 x 4-ch. TPM with PWM 2 x SCI
MCG
VREF TOD
PRACMP CMT
2 x 4-ch. TPM with PWM 2 x SPI
2 x KBI 2 x SCI
32-bit V1 ColdFire 50 MHz Core with MAC
VREF TOD
PRACMP CMT
2 x KBI 2 x SPI
8-bit 9S08 48 MHz Core
Up to 68 GPIO/
16 RGPIO
16-bit SAR ADC I2 12-bit DAC LVI
C
MiniBus External
USB
Device/Host/
OTG
Bootloader
256 KB 32 KB SRAM
USB ROM
Up to 68 GPIO
USB
Device
Bootloader
128 KB Flash 12 KB SRAM
USB ROM
30 Medical Applications User Guide

Heart Rate Monitor
5.1
Introduction
Heart rate monitors measure the heart rate during exercise or vigorous activity
and gauge how hard the patient is working. Newer heart rate monitors consist
of two main components: a signal acquisition sensor/transmitter and a receiver
(wrist watch or smartphone). In some cases, the signal acquisition is integrated
into fabric worn by the user or patient. MCUs analyze the ECG signal and
determine the heart rate, making possible to implement a simple heart rate
monitor with an 8-bit MCU.
5.2
Heart Signals Overview
Figure 5-1 shows a typical heart signal. In this
signal, the heart muscles generate different
voltages. P represents an atrial depolarization.
Q, R, S and T represent the depolarization and
repolarization of the ventricles. Each time this
signal is present, a heartbeat is generated.
The principal purpose of this application is
to provide a heartbeat average, so it is only
necessary to work with the QRS complex (see
section 5-4, Obtaining QRS Complexes). For
this reason it is important to develop analog
and digital signal conditioning. First, the signal
is amplified and the noise is filtered, and then
the QRS complex can be detected.
freescale .com/medical 31

Home Portable Medical
5.3
Filters and Amplification
Noise and interference signals acquired
in this type of system can be caused by
electricity, such as radiation from electricpowered
fluorescent lamps. These generate
a lot of common-mode voltage and noise.
Other aspects that generate noise are muscle
contractions, respiration, electromagnetic
interference and noise from electronic
components. Because the electrical signals
from the heart are not strong enough, it is
necessary to amplify the signals and reduce
the common-mode voltage in the system.
Cardiac motion generates electrical currents
with different potentials in the body. These can
be sensed with electrodes, usually connected
to the right and left hands. The electrical
potential is an AC signal in a bandwidth
from 0.1 Hz to 150 Hz with a magnitude of
approximately 1 mV peak to peak, and with
presence of common-mode voltage noise in
a frequency range from approximately 40 Hz
to 60 Hz. Knowing this information, a circuit
can be designed for amplification and filtration
(see figures 5-3, 5-4, 5-5 and 5-6 for details).
5.4
Amplifier and Filtering
Requirements
The amplification is fixed at 1000 with a
band-pass filter and cut frequencies of 0.1 Hz
and 150 Hz. The reject-band filter has cut
frequencies of 40 Hz and 60 Hz.
Frequency Response
• Diagnostic grade monitoring
-3 dB frequency, bandwidth of 0.1 Hz–150 Hz
• Band-pass filter
Rl = 1 kΩ R = 1.5 MΩ C = C = 1 uF
p hp lp hp
• AC line noise
-3 dB frequency bandwidth of 40 Hz–60 Hz
• Reject–band filter
R = 1 kΩ R = 1.5 MΩ C = 4 uF C = 1.7 nF
lp hp lp hp
This application requires two types of
amplifiers: an instrumentation amplifier and an
operational amplifier.
Figure Figure 5-1: 5-1: Typical Typical Heart Heart Signal Signal
P T
Figure 5-2: Heart Rate Monitor (HRM) General Block Diagram
Heart Rate Monitor (HRM)
Special Conductive
Glove or Finger Touch
to Conductive Area
Amplifier
Power
LED
Coin Cell
Battery
Coin Cell
Battery
Amplifier
Freescale Technology Optional
32 Medical Applications User Guide
ADC
ADC
Conductive Rubber Chest Strap
or Special Clothing
Display
MCU
USB
To PC
MCU
Q
R
S
Keypad
Receiver/
Amplifier
Antenna
Figure 5-3: Signal Conditioning Block Diagram
Figure 5-3: Signal Conditioning Block Diagram
Instrumentation
Amplifier
Amp and
Modulator
Antenna
PWM
Wireless
Comm
Speaker Drive
Circuitry
To Remote
Sensor System
Main
Receiver System
To Main
Receiver
System
Remote
Sensor System
ADC

Instrumentation amplifier requirements
include:
• Low gain 10
• High common-mode rejection ratio (CMRR)
• Low offset
R1 = 500 Ω R2 = 4.5 kΩ
Requirements for the operational amplifier, the
second part of the instrumentation amplifier,
include:
• High gain 100
• Output voltage around 1V
• Low offset
R3 = 1 kΩ R2 = 100 kΩ
5.5
Obtaining QRS Complexes
The QRS complex has to be detected in
every heartbeat. This complex is the highest
peak generated from the heart waveform.
Although the signal has been filtered and
amplified, it is necessary to include a digital
band-pass filter with a bandwidth of 10 Hz
to 25 Hz to remove high-frequency noise and
low-frequency drift. Afterwards, filtering a
derivation is implemented and a threshold is
taken to determine whether the data is part of
the QRS signal.
5.6
Heart Rate Monitor Design
For more information on how to design a
heart rate monitor, refer to AN4323: Freescale
solutions for Electrocardiograph and Heart
Rate Monitor Applications.
This application note describes how to use the
MED-EKG development board, a highly efficient
board that can be connected to the Freescale
Tower System to obtain an electrocardiogram
signal and measure heart rate.
The application is implemented using
either the MK53N512, MC9S08MM128 or
MCF51MM256 MCUs.
Home Portable Medical
Figure 5-4: 5-4: Instrument Instrument Amplifier Amplifier to Acquire to Acquire Heart Heart Signal Signal
Vi 1
Vid=
(Vi 1 -Vi 2 )
Vi 2
2R 1
Figure 5-5: Passive Band-Pass Filter Circuit Operating Frequencies 0.1 Hz-150 Hz
Figure 5-5: Band-Pass Filter Circuit Operating Frequencies 0.1 Hz–150 Hz
Figure 5-6: Active Band-Pass Filter Circuit Operating Frequencies 0.1 Hz-150 Hz
Figure 5-6: Band-Pass Filter Circuit Operating Frequencies 0.1 Hz–150 Hz
Figure 5-7: Digital Signal Processing to Obtain the QRS Complex
Figure 5-7: Digital Signal Processing to Obtain the QRS Complex
X(n)
Raw ECG
LPF
HPF
Differentiate
Integrate
freescale .com/medical 33
R 2
Vid/2R1 R2 Y(n)
R 3
R 3
Q
Vid(1+2R 2 /2R 1 )
R
S
R 4
R 4
Square
Vo=R 4 /R 3 ( 1+R 2 /R 1 )Vid
A=Vo/Vid

Blood Glucose Meter
6.1
Introduction
A glucometer is a device for determining the approximate
concentration of glucose in the blood. It is a key element of homebased
blood glucose monitoring (BGM) for people with diabetes
mellitus (Type 1 and 2).
The conductivity of blood is affected by the quantity of glucose
present. This is the principle used to determine the concentration of
glucose in a sample of blood. This biological phenomenon can be
modeled with an electrical circuit where a variable resistor is connected
in series with a resistor to a fixed voltage source. The voltage drop in
the variable resistance is determined by conductivity of the resistance.
When the conductivity is high, the voltage drop is low, and when the
conductivity is low, the voltage drop is high. These variations can be
analyzed to determine the glucose concentration.
34 Medical Applications User Guide

6.2
Test Strip
A test strip consists of an electrode with
chemical elements where a blood sample is
deposited. The elements present in the strip
generate a reaction and an electric current is
sent to a transimpedance amplifier that converts
the current into voltage. The output voltage is
proportional to the input current, following the
equation of the transimpedance amplifier.
The transimpedance amplifier embedded on
the Kinetis MK50 and the Flexis MM MCUs
(S08MM and MCF51MM) allows the user to
acquire the current generated by the glucose’s
chemical reaction to the enzyme. The external
components are used to configure the desired
gain value of the amplifier. The transimpedance
module is called TRIAMPV1 and it is managed
through the values of the TIAMPCO register.
The TIAMPEN bit of this register enables the
transimpedance module and the LPEN bit
enables low-power mode (LPEN = 1) and
high-speed mode (LPEN = 0). Low-power
mode is commonly used for battery-dependent
systems, but it compromises the response
speed of the system.
The TRIOUT pin of this module must be
connected with an external resistor (gain
resistor) to the VINN pin, which is the inverting
input of the operational amplifier. The VINP pin
must be connected to ground.
A general block diagram of the test strip is
shown in Figure 6-4.
The basic sensor for a glucometer is an enzymatic
strip. These are based on the detection of
hydrogen peroxide formed in the course of
enzyme-catalyzed oxidation of glucose.
Glucose GOD gluconolactone hydrogen
peroxide
C6H12O6 → C6H10O6 + H2O2
These strips are amperometric sensors that
use a three-electrode design. This approach
is useful when using amperometric sensors
because of the reliability of measuring voltage
and current in the same chemical reaction.
The three-electrode model uses a working
electrode (WE), reference electrode (RE) and
counter electrode (CE).
Home Portable Medical
Figure 6-1: Blood Glucose Monitor (BGM) General Block Diagram
Blood Glucose Monitor (BGM)
Wireless
Comm
Keypad
MCU/MPU
DAC
ADC
opAmp
Power
Management
Freescale Technology Optional
Figure Figure 6-2: 6-2: Equivalent Equivalent Circuit Circuit with with Rv Equal Rv Equal to Blood to Blood Conductivity Conductivity
Figure 6-3: Basic Transimpedance Amplifier
Figure 6-3: Basic Transimpedance Amplifier
freescale .com/medical 35
Vi
li
R
R V
Vo =-li x Rf
R2
U1
Display
Test Strip
Vo=Vi Rv
R+Rv
Figure 6-4: Test Strip Basic Block Diagram Using Flexis MM
Figure 6-4: Test Strip Basic Block Diagram Using Flexis MM
Blood
Sample
Reactive
Electrode
External
Components
Vo
Vo
Embedded
Transimpedance
Amplifier
MCU/MPU
PWM
Embedded
ADC

Home Portable Medical
AN4364: Glucose Meter
Fundamentals and Design
This application note shows a basic
glucometer implementing Freescale K53,
S08MM128 and MCF51MM MCUs. The
application uses the MED-GLU board, which
is a development board to enable the rapid
prototyping of glucose meters by connecting
it to the Freescale Tower System through
the medical connector on medical-oriented
MCU modules.
K50 Measurement MCUs
The K50 MCU family is pin, peripheral and
software compatible with other Kinetis MCUs
and provides designers with an analog
measurement engine consisting of integrated
operational and transimpedance amplifiers
and high-resolution ADC and DAC modules.
The family also features IEEE 1588 Ethernet
and hardware encryption, full-speed USB
2.0 On-The-Go with device charger detect
capability and a flexible low-power segment
LCD controller with support for up to 320
segments. Devices start from 128 KB of flash
in 64-pin QFN packages extending up to 512
KB in a 144-pin MAPBGA package.
Key Features
Kinetis K50 MCU features and peripherals in
the integrated measurement engine:
• Ultra-low-power operation
• 2x OPAMP
• 2x TRIAMP
• 2x 12-bit DAC
• 2x 16-bit SAR ADC, up to 31 channels with
programmable gain amplifiers (PGA)
• Programmable Delay Block (PDB)
• I2C • USB connectivity
• ARM Cortex-M4 core with DSP (Digital
Signal Processor) instructions
MCF51MM: Flexis 32-bit ColdFire
V1 MCUs
The MCF51MM256/128 provides ultralow-power
operation, USB connectivity,
graphic display support and unparalleled
measurement accuracy, all in a single 32-bit
MCU, allowing designers to create more
Figure 6-5: Kinetis K50 Family Block Diagram
Figure 9-8 Kinetis K50 Family
Security
and Integrity
Cyclic
Redundancy
Check (CRC)
Random
Number
Generator
Cryptographic
Acceleration
Unit (CAU)
Figure
Figure
6-6:
6-6:
MCF51MM256
MCF51MM256
Block
Block
Diagram
Diagram
2x OPAMP
2x TRIAMP
16-bit SAR ADC I2 12-bit DAC LVI
C
PDB
2 x 4-ch. TPM with PWM 2 x SPI
MCG
Core
ARM ® Cortex-M4
72/100 MHz
Debug
Interfaces
Interrupt
Controller
Standard Feature
System Memories
Internal and
External
Watchdogs
Memory
Protection Unit
(MPU)
VREF TOD
PRACMP CMT
2 x KBI 2 x SCI
32-bit V1 ColdFire 50 MHz Core with MAC
Up to 68 GPIO/
16 RGPIO
MiniBus External
USB
Device/Host/
OTG
Bootloader
256 KB 32 KB SRAM
USB ROM
Xtrinsic
Low-Power
Touch-Sensing
Interface
Segment
LCD Controller
36 Medical Applications User Guide
DSP
Analog
16-bit
ADC
PGA
Analog
Comparator
6-bit
DAC
12-bit
DAC
Voltage
Reference
OPAMP
TRIAMP
DMA
Low-Leakage
Wake-Up Unit
Timers
FlexTimer
Carrier
Modulator
Transmitter
Programmable
Delay Block
Periodic
Interrupt
Timer
Low-Power
Timer
Independent
Real-Time
Clock (IRTC)
IEEE ® 1588
Timer
Optional Feature
Program
Flash
(128 to 512 KB)
FlexMemory
(32 to 256 KB)
(2 to 4 KB EE)
Serial
Programming
Interface
(EZPort)
SRAM
(32 to 128 KB)
External
Bus Interface
(FlexBus)
Clocks
Phase-Locked
Loop
Frequency-
Locked Loop
Low/High-
Frequency
Oscillators
Internal
Reference
Clocks
Communication Interfaces HMI
I 2 C
UART
(ISO 7816)
SPI
IEEE 1588
Ethernet MAC
I 2 S
Secure
Digital Host
Controller
(SDHC)
USB OTG
(LS/FS)
USB Charger
Detect (DCD)
USB Voltage
Regulator
GPIO

fully featured products at lower cost. The
MCF51MM256/128 is ideal for medical
applications or other applications requiring a
significant amount of precision analog such as
instrumentation and industrial control.
The MCF51MM256/128 is part of the
Freescale Flexis MCU series.
Features:
• ColdFire V1 core delivering a 50 MHz core
speed and 25 MHz bus speed
• Up to 256 KB flash and 32 KB SRAM
• Low-power stop 2 current: 500 nA
(32 KB of active SRAM)
• 2 x general purpose opamps
• 2 x transimpedance amplifiers
• 16-bit SAR high resolution analog-to-digital
converter (ADC)
• Analog Comparator with 5-bit digital-toanalog
converter (DAC)
• Internal voltage reference
• USB – device/host/on-the-go controller
• 2 x serial peripheral interface (SPI),
2 x serial communication interface (SCI)
and 1 x I2C • Mini FlexBus (external bus interface EBI)
• Included in Freescale’s Product Longevity
Program
S08MM: Flexis 8-bit MCUs
The 9S08MM128/64/32 provides ultralow-power
operation, USB connectivity,
graphic display support and unparalleled
measurement accuracy, all in a single 8-bit
MCU, allowing device designers to create
more fully featured products at a lower cost.
It is ideal for applications requiring a
significant amount of precision analog.
The 9S08MM128/64/32 is part of Freescale’s
Flexis MCU series.
Features
• S08 core delivering a 48 MHz core speed
and 24 MHz bus speed
• Up to 128 KB flash and 12 KB SRAM
• Low-power stop 2 current: 450nA
(12 KB of active SRAM)
• 2 x OPAMP- General purpose opamps
• 2 x TRIAMP- Transimpedance amplifiers
Figure 6-7: MC9S08MM128 Block Diagram
Figure 6-7: MC9S08MM128 Block Diagram
Figure 6-9: MED GLU Block Diagram
Figure 6-5: MED GLU Block Diagram
Test Strip
Vref
(-0.4V)
Voltage
Inverter
2x OPAMP
2x TRIAMP
PDB
2 x 4-ch. TPM with PWM 2 x SCI
MCG
3.3V
Vref
(1.2V)
VREF TOD
PRACMP CMT
2 x KBI 2 x SPI
8-bit 9S08 48 MHz Core
Current to voltage
converter
Freescale Technology MM/K5x Internal
Home Portable Medical
16-bit SAR ADC I2 12-bit DAC LVI
C
Low Pass
Filter
Low Pass
Filter
freescale .com/medical 37
TriAmp
TriAmp
OpAmp
OpAmp
Up to 68 GPIO
USB
Device
Bootloader
128 KB Flash 12 KB SRAM
USB ROM
Figure 6-8: Chip Schematic
Figure 6-8: Chip Schematic
2
3
1
4 5
1) WE, 2) CE, 3) Ag/AgCI RE, 4) Conductive lines, 5) Pads
ADC
ADC

Home Portable Medical
• 16-bit SAR analog-to-digital converter
(ADC) – high resolution ADC
• Analog comparator
• Internal voltage reference
• USB device controller
• 2 x serial peripheral interface (SPI),
2 x serial communications interface (SCI)
and 1 x I2C 6.3
Wired and Wireless
Communication
The functionality of a blood glucose meter
can be expanded to allow wired or wireless
communication with other devices such as
PDAs, smart phones, insulin dispensers or
calorimeters. This can be useful for telehealth
applications and remote patient monitoring.
Freescale offers several cost-effective lowpower
MCUs with integrated USB interfaces
for wired communication. For wireless
options, Freescale offers ZigBee solutions and
examples in its own BeeKit. Figure 6-10 is an
example of ZigBee implementation.
See Chapter 3.10, Wireless Communication,
for more details.
6.4
Liquid Crystal Display
(LCD) Module
The LCD module shows the glucose level.
Freescale provides an application note titled
LCD Driver Specification (document AN3796)
about how to implement an LCD controller
and the driver software. The application note
is available at freescale.com.
The capacity of digits is determined by the
LCD used. It must be supported by the
number of segments that can drive the LCD
controller. The MC9S08LL16 processor
supports up to 4 x 28 or 8 x 24 segments.
Figure 6-10: Example of Communication Interface for Blood Glucose Monitor
Figure 6-10: Example of Communication Interface for Blood Glucose Monitor
Patient
Blood Glucose
Monitor
Figure 6-11: LCD Connection
Figure 6-11: LCD Connection
Charge
Pump
Frontplanes
Twisted Nematic Display
Backplanes
38 Medical Applications User Guide
VLL
S08LL: S08 Ultra-Low-Power
MCU with LCD Driver
Antenna
ZigBee ®
Transceiver
MCU with
LCD controller
Key Features
• Up to 20 MHZ HCS08 CPU from 1.8V to
3.6V and across a temperature range of
-40°C to +85°C
• Two ultra-low-power stop modes
• Advanced low-power run and wait modes
• Internal clock source (ICS)
• Integrated LCD driver supports both 3V and
5V LCD glass standards
• Configurable display for 8 x 36 or 4 x 28
segment display
• LCD driver pins are mixed with GPIO and
other functions
Antenna
ZigBee
Transceiver
Remote
Monitoring System
• Up to 64 KB flash read, program and erase
over full operating voltage and temperature
• Analog-to-digital converter (ADC)—
10-channel, 12-bit resolution
• Timer—Two 2-channel
• Two serial communications interface (SCI)
• Analog comparator with selectable
interrupt on rising, falling or either edge of
comparator output
• Serial peripheral interface (SPI)—
One module with full-duplex or singlewire
bidirectional
• I²C with up to 100 kbps
• 38 general purpose input and output
(GPIO), two output-only pins
• Single-wire background debug interface

Freescale’s Xtrinsic accelerometer MMA845xQ
family offers extremely low power and pin
compatibility with a broad range of resolution
(14-, 12- and 10-bit) and embedded features
for configurable, accurate motion analysis.
To operate with extremely low power, the
MMA845xQ accelerometers have six userconfigurable
sample rates that can be set
over a wide range of 1.5 to 800 Hz.
With the increasing consumer focus in the
design of medical devices, inertial sensors
are also being used for simple portrait and
landscape functionality to improve the enduser
experience. This is especially applicable
for high-end blood glucose meters with
graphical displays.
Xtrinsic MMA845xQ: 3-Axis Digital
Output Acceleration Sensor
Key Features
• Low-power current consumption
o Off mode: 50 nA
o Standby mode: 2 uA
o Active mode: 6-166 uA
• Low-voltage operation: 1.95-3.6 volts
• Embedded features include:
o Freefall detection
o Orientation detection
o Tap detect
o Shake detect
o Auto-wake sleep
Home Portable Medical
Figure 6-12: Implementation of the Digital Accelerometer
Figure 6-12: Implementation of the Digital Accelerometer
Digital Output
Accelerometer
2/4 Wire I²C/SPI Bus
freescale .com/medical 39
MCU
Figure 6-13: Xtrinsic MMA845xQ 3-Axis Digital Output Acceleration Sensor
MMA845xQ Block Diagram
Vdd
VddIO
VSS
X-axis
Transducer
Y-axis
Transducer
Z-axis
Transducer
32 Data Point
Configurable
FIFO Buffer
with Watermark
Freefall and
Motion
Detection
C to V
Converter
Configurable Embedded DSP Functions
Transient
Detection
(i.e., fast
motion, jolt)
Enhanced
Orientation with
Hysteresis
and Z-lockout
Shake
Detection
through Motion
Threshold
INT1
INT2
Single, Double
& Directional
Tap Detection
Auto-Wake/Auto-Sleep Configurable with debounce counter and multiple motion interrupts for control
MODE Options
Low Power
Low Noise + Power
High Resolution
Normal
ACTIVE Mode
WAKE
Internal
OSC
Auto-WAKE/SLEEP
Clock
GEN
14-bit
ADC
ACTIVE Mode
SLEEP
Embedded
DSP
Functions
I 2 C
MODE Options
Low Power
Low Noise + Power
High Resolution
Normal
SDA
SCL

Pulse Oximetry
7.1
Theory Overview
Oxygen saturation (SpO2) is defined as the ratio of oxyhemoglobin
(HbO2) to the total concentration of hemoglobin (HbO2 +
deoxyhemoglobin). The percentage is calculated by multiplying this
ratio by 100. Two different light wavelengths are used to measure
the actual difference in the absorption spectra of HbO2 and Hb.
The bloodstream is affected by the concentration of HbO2 and Hb
and their absorption coefficients are measured at two measurement
wavelengths. The light intensity decreases logarithmically with the path
length according to the Beer-Lambert Law. It is important to mention
that when the light attenuated by body tissue is measured,
DC components and AC components indicate artery absorption.
40 Medical Applications User Guide

7.2
Signal Acquisition
This application is non-invasive because the
optical sensor is composed of two LEDs
that transmit light through the skin (finger
or earlobe) to a photodiode. One LED is red
with a wavelength of 660 nm and the other is
infrared with a wavelength of 910 nm. The skin
absorbs the light received by the photodiode.
Each wavelength provides different data to
calculate the percentage of hemoglobin.
Deoxygenated and oxygenated hemoglobin
absorb different wavelengths. Deoxygenated
hemoglobin has absorption of around 660
nm and oxygenated hemoglobin has higher
absorption at 910 nm. These signals depend
on the actual blood pressure, therefore the
heart rate can also be measured.
SaO2 as R
R = log 10 (I ac ) λ1
log10(I ac ) λ2
Iac= Light intensity at λ1 or λ2, where only AC level
is present λ1 or λ2 are the wavelengths used.
7.3
Circuit Design Overview
This application starts with an optical
sensor that is composed of two LEDs and
a photodiode. The two LEDs have to be
multiplexed to turn on. The photodiode detects
when light is present by detecting current that
is proportional to the intensity of the light,
then the application uses a transimpedance
amplifier to convert this current into voltage.
Automatic gain control (AGC) controls the
intensity of LEDs depending on each patient.
A digital filter then extracts the DC component.
The signal is passed to a digital band-pass
filter (0.5 Hz–5 Hz) to get the AC component,
then through a zero-crossing application to
measure every heartbeat. Finally, this signal is
passed as a voltage reference to the second
differential amplifier to extract only the DC
component and separate the AC and DC
components. After this, the following ratio
formula to obtain the oxygenated hemoglobin
(SaO2) levels is used:
R = [log (RMS value) x 660 nm] / [log (RMS
value) x 940 nm]
Home Portable Medical
Figure 7-1: Spectrum of Oxyhemoglobin and Deoxyhemoglobin
Figure 7-1: Spectrum of Oxyhemoglobin and Deoxyhemoglobin
Extinction Coeffiecient 10(RED)
0.1
freescale .com/medical 41
600
660 nm
(INFRARED)
940 nm
700 800 900 1000
Wavelength (nm)
Figure 7-2: Pulse Oximetry Analog Interface
Figure 7-2: Pulse Oximetry Analog Interface
External
LED and Driver
Transimpedance
Amplifier
RBF
(40 Hz-60 Hz)
Display
LED Red On/Off
LED Red On/Off
LED Red Brightness
Infrared Brightness
Photodiode
Demultiplexer
Hear Rate
Monitor
SaO 2
Pseudo Analog
Ground
Differential
Amplifier
Zero
Crossing
LED Red and
Infrared Sensors
DAC_0
DAC_1
Digital Band
Pass Filter
HbO2
Hb
LED On/Off
MCU Pins
Select 0/1
LED Range
Control
Multiplexer
DC Tracking
LPF (below
0.5 Hz)
Signal Conditioning
AC Components
ADC

Home Portable Medical
7.3.1
Circuit LED Driver
The circuit is used for both red and infrared
LEDs. When the LEDs are placed in parallel
they can be multiplexed. Two ports of the
DAC_0 control the brightness of the LEDs.
The MCU controls brightness and multiplexing
frequency of the LEDs depending on the
designer’s specifications. The LEDs are turned
on and off to calculate the ratio between both
signals and compute the amount of oxygen
saturation.
7.3.2
Signal Processing
The current proportioned by the photodiode
depends on the intensity of the light. This
signal has to be changed to voltage and
amplified by the transimpedance amplifier.
The signal generated is around 1V for DC
and 10 mV for AC. Freescale’s S08MM
has four integrated op-amps. Both of the
transimpedance and non-inverting amplifiers
shown in figure 7-5, as well as more active
filters, can be developed using this MCU. The
AC component is generated by the oxygen
present in the blood; to process the signal it is
only necessary to obtain the AC component.
A digital filter is placed to remove the DC
component and this filter is taken as a voltage
reference for the second amplifier.
The DC tracking filter allows the system to
separate the DC and AC components. The AC
component is used to calculate oxygen levels
and to detect zero crossing to detect the
heartbeat. The digital filter can be developed
using Freescale’s MC56f8006 DSC. The
information can be shown on any kind of
display.
For wireless communication, power
management, keypad and speaker
implementation, see Chapter 3 Introduction.
Figure Figure 7-3: 7-3: Optical Optical Sensor Sensor
Figure 7-4: 7-4: LED LED Drive Drive Circuit Circuit
Figure 7-5: DC/AC Tracking
Figure 7-5: DC/AC Tracking
The extracted DC is composed of ADC-DC tracking-DAC
Figure 7-6: MED-SP02 Block Diagram
Figure 7-6: MED-SP02 Block Diagram
PWM
GPIO
Red Amplifier
1 Red Amplifier
Current to Voltage converter
R/IR Control using K53 TRIAMP R/IR Control
1 Red Baseline Red Baseline
Red Red LED
Filter and Amplification R/IR Control
Vref Generator
Red Amplifier
1 Red Amplifier
42 K53 Measurement Engine Filter Amplifier Multiplexer Medical Applications Circuit User Guide
1 Red
LED
Driver
Finger or Earlobe
1 Red LED
LEDs
SP02
Sensor
ADC
Vref

AN4327 Pulse Oximeter
Fundamentals and Design
This application note demonstrates the
implementation of a pulse oximeter using the
medical-oriented MCU MK53N512 together
with the pulse oximeter development board
MED-SPO2. Basic principles of implantation
and example code are included enabling
developers with an easy and effective pulse
oximeter solution.
Kinetis K40 MCU
The Kinetis K40 72 MHz MCUs are pin,
peripheral and software compatible with
the K10 MCU family featuring full-speed
USB 2.0 On-The-Go, with device charge
detect capability and a flexible low-power
segment LCD controller supporting up to
288 segments.
Key Features
• 72 MHz, single cycle MAC, single
instruction multiple data (SIMD) extensions
• 64-256 KB flash. Fast access, high
reliability with 4-level security protection
and 16-64 KB of SRAM
• USB 2.0 On-The-Go (full speed). Device
charge detect optimizes charging current/
time for portable USB devices enabling
longer battery life. Low-voltage regulator
supplies up to 120 mA off chip at 3.3V to
power external components from 5V input
• Flexible, low-power LCD controller with up
to 288 segments (38x8 or 42x4). LCD blink
mode enables low average power while
remaining in low-power mode. Segment fail
detect guards against erroneous readouts
and reduces LCD test costs.
Figure 7-7: Pulse Oximeter Block Diagram
Figure 0-2: Baseline Correction Using DAC
Band-Reject filter
ADC
Freescale Technology
High-Pass filter
Baseline Baseline
Correction
Figure 7-8: Kinetis K40 Family Block Diagram
Figure 7-8: Kinetis K40 Family
Security
and Integrity
Cyclic
Redundancy
Check (CRC)
Core
ARM ® Cortex-M4
72/100 MHz
Debug
Interfaces
Interrupt
Controller
Standard Feature
Home Portable Medical
freescale .com/medical 43
DSP
Analog
16-bit
ADC
PGA
Analog
Comparator
6-bit
DAC
12-bit
DAC
Voltage
Reference
Timers
DAC
System Memories
Internal and
External
Watchdogs
Memory
Protection Unit
(MPU)
DMA
Low-Leakage
Wake Up Unit
Flex
Timer
Carrier
Modulator
Transmitter
Programmable
Delay Block
Periodic
Interrupt
Timers
Low-Power
Timer
Independent
Real-Time
Clock (RTC)
Optional Feature
Program Flash
(64 to 512KB)
FlexMemory
(32 to 256KB)
(2 to 4KB EE)
Serial
Programming
Interface
(EzPort)
SRAM
(16 to 128KB)
External
Bus Interface
(FlexBus)
ADC
Clocks
Phase-Locked
Loop
Frequency-
Locked Loop
Low/High-
Frequency
Oscillators
Internal
Reference
Clocks
Communication Interfaces HMI
I 2 C
UART
(ISO 7816)
SPI
CAN
I 2 S
Secure
Digital Host
Controller
(SDHC)
USB OTG
(LS/FS/HS)
USB Charger
Detect (DCD)
USB Voltage
Regulator
GPIO
Xtrinsic Low-
Power
Touch-Sensing
Interface
Segment
LCD Controller

Activity Monitor
8.1
Introduction
An activity monitor is an auxiliary healthcare device for the management of sports and fitness
activities. It keeps a record of the user activities, calories burned, energy consumed in food as
well as other useful features for diet control and exercise performance.
This device can register the heart rate, allowing a better management of the exercise efficacy.
It monitors physical performance using auxiliary modules like a pedometer, timer, and
chronometer. A personal data record including age, height and weight provide a more accurate
calculation of caloric consumption.
By monitoring individual parameters of a person, the health and fitness ecosystem can be built
online so data can be utilized for individual performance. This goes beyond simply tracking
calories and other data to create more personalization and behavior modification.
The information is stored in a microSD memory card and can be accessed with a computer
either directly from the memory, via USB cable or wirelessly and then can be analyzed.
44 Medical Applications User Guide

8.2
Electrocardiography
(ECG) Acquisition
The heart rate calculation is performed using
the ECG signal. The heart beat frequency is
determined by measuring the time between
QRS complex intervals. The ECG signal
is acquired using two finger sensors, one
on each side of the device. The first one
takes the signal from the left index finger.
The second one is divided in two parts: one
takes the signal from the right index finger,
the other works as reference.
The signal is amplified using an
instrumentation amplifier built by using the
internal op amps of the Flexis MM MCU
or the Kinetis K5x MCU, which has a high
common mode rejection ratio (CMRR) that
allows it to work as an initial filter. Then,
the signal must go through a 0.1 Hz – 150
Hz band-pass filter in order to remove the
environmental noise. A second filter must
be applied. In this case, a 50 Hz – 60 Hz
notch filter, depending on the country’s
electrical service frequency. This second
filter is intended to remove the power
line noise, which equals 50 Hz or 60 Hz,
depending on the region. Finally, the signal
must be acquired by an MCU using an ADC.
Optionally, the MCU can perform digital
filtering algorithms in order to have a more
reliable signal.
8.3
Pedometer
The pedometer counts the quantity of steps
taken by the user while the activity monitor
is activated. Accelerometers can be used
to determine the overall activity level of the
user. This module uses an accelerometer to
determine device movement, and it must be
able to detect when a step has been taken
or whether the user starts running. The
acceleration measurements recorded by the
accelerometer are sent to an MCU either
by using analog voltages to represent the
movement, or by using digital methods such
as I2C to send previously processed signals.
Figure 8-1: Activity Monitor Block Diagram
Magnetic Sensor:
eCompass
Heart Rate
Monitor
USB
Mini-AB
Power Management:
Battery Charger
Inertial
Sensor:
Pedometer
OPAMPS
TRIAMPS
Freescale Technology Optional
External
Bus/GPIO
Touch Sensing
freescale .com/medical 45
VREF
Pressure
Sensor
Altimeter
MicroSD
Card
I 2 C I 2 C SPI 1 SPI 2
MCU/MPU
GPIO
USB PWM
Li-Polymer
Battery
Display
Figure 8-2: ECG Acquisition Block Diagram
Figure 10-3: Block Diagram ECG Acquisition Block Diagram
LA
RA Ref
Finger Electrodes Instrumentation Amplifier
Freescale Technology
Home Portable Medical
0.1 Hz – 150 Hz
Band Pass
Wireless Communication:
ZigBee ®
50 Hz – 60 Hz
Band Reject
Buzzer
MCU

Home Portable Medical
MMA845xQ Accelerometers
Freescale’s Xtrinsic accelerometer MMA845xQ
family offers extremely low power and pin
compatibility with a broad range of resolution
(14-, 12- and 10-bit) and embedded features
for configurable, accurate motion analysis.
To operate with extremely low power, the
MMA845xQ accelerometers have six userconfigurable
sample rates that can be set over
a wide range of 1.5 to 800 Hz. The power
scheme contains four different power modes
from high resolution to low power, offering
best-in-class savings in supply current and
extremely high resolution for very small motion
detection.
Features
• Low-power current consumption
o Off mode: 50 nA
o Standby mode: 2 uA
o Active mode: 6-166 uA
• Low-voltage operation: 1.95-3.6 volts
• Embedded features include:
o Freefall detection
o Orientation detection
o Tap detect
o Shake detect
o Auto-wake sleep
MMA9553L Intelligent Motion
Sensing Platform
Freescale’s Xtrinsic MMA9550L intelligent
motion sensing platform is an industry first
with integration of a MEMS accelerometer,
a 32-bit embedded ColdFire MCU, flash
memory and a dedicated architecture to
manage other sensors. Freescale has now
expanded the MMA9550L offering with the
MMA9553L to enable pedometer functionality.
The MMA9553L intelligent motion sensing
platform performs activity monitoring beyond
step counting. This entails recognition of
motion such as rest, walking, jogging and
running.
Figure 8-3: MMA845xQ Block Diagram
MMA845xQ Block Diagram
Vdd
VddIO
VSS
X-axis
Transducer
Y-axis
Transducer
Z-axis
Transducer
32 Data Point
Configurable
FIFO Buffer
with Watermark
Freefall and
Motion
Detection
C to V
Converter
Configurable Embedded DSP Functions
Transient
Detection
(i.e., fast
motion, jolt)
Enhanced
Orientation with
Hysteresis
and Z-lockout
Shake
Detection
through Motion
Threshold
46 Medical Applications User Guide
INT1
INT2
Single, Double
& Directional
Tap Detection
Auto-Wake/Auto-Sleep Configurable with debounce counter and multiple motion interrupts for control
MODE Options
Low Power
Low Noise + Power
High Resolution
Normal
ACTIVE Mode
WAKE
Internal
OSC
Auto-WAKE/SLEEP
Features
• Communication protocols: I2C/SPI • Low-voltage operation: 1.71 V to 1.89 V
• Embedded smart FIFO for data processing
while apps processor is asleep
• Configurable sample rate: 1–1024
samples/sec
• Auto-wake monitors change in activity/
position
• Embedded features include:
o Orientation detection
o Single, Double and Directional Tap detect
o Single, Double and Directional Shake
o Threshold detection
o Linear and rotational freefall
o Flick detection
o Tilt angle
Clock
GEN
14-bit
ADC
ACTIVE Mode
SLEEP
Embedded
DSP
Functions
8.4
User Interface
I 2 C
MODE Options
Low Power
Low Noise + Power
High Resolution
Normal
SDA
SCL
The user interface is an essential part in the
activity monitor development. It must be
simple and intuitive, as well as attractive for
the user. The use of graphic displays makes
the activity monitor easier and more intuitive
to use, and it also adds aesthetics to the
design. MCUs with External Bus Interface
(EBI) reduce the processor’s load allowing for
better quality graphics with reduced processor
intervention.
The touch-sensing interfaces (TSI) make the
design an attractive and functional application
by removing the need for mechanic buttons.
In addition, the TSIs are easier to clean and
are more hygienic.

Xtrinsic Touch-Sensing Software
Xtrinsic Touch-Sensing Software (TSS)
transforms any standard MCU into a touch
sensor with the ability to manage multiple
configurations of touchpads, sliders, rotary
positions and mechanical keys, all while
maintaining standard MCU functionality.
8.5
Reference Designs
Freescale provides ready-to-develop
applications intended to reduce the
development time and, therefore, time to
market and costs. The following documents
include useful information in the development
of activity monitor applications:
DRM125 Activity Monitor
AN4323 Freescale Solutions for
Electrocardiograph and Heart Rate Monitor
Applications
AN4519 Data Manipulation and Basic
Settings of the MPL3115A2 Command
Line Interface Driver Code
S08MM: Flexis 8-bit MCUs
The 9S08MM128/64/32 provides ultralow-power
operation, USB connectivity,
graphic display support and unparalleled
measurement accuracy, all in a single 8-bit
MCU, allowing device designers to create
more fully featured products at a lower cost. It
is ideal for applications requiring a significant
amount of precision analog.
The 9S08MM128/64/32 is part of Freescale’s
Flexis MCU series.
Figure 8-4: Xtrinsic MMA9553L Intelligent Motion Sensing Block Diagram
Xtrinsic MMA9550L Block Diagram
Power
Management
Inertial
Sensor
MMA9550L Sensor Sensing Software
V1 ColdFire
32-Bit Processor
16K Flash,
8K User Programmable,
2K RAM, 1K User RAM
Connectivity:
I2C/SPI
Gyro Pressure Touch Magnetics
Figure
Figure
9-10:
8-5:
MC9S08MM128
MC9S08MM128
Block
Block
Diagram
Diagram
2x OPAMP
2x TRIAMP
PDB
MCG
VREF TOD
PRACMP CMT
2 x 4-ch. TPM with PWM 2 x SCI
2 x KBI 2 x SPI
8-bit 9S08 48 MHz Core
Home Portable Medical
Customer/Third-Party
Innovation
Applications
Software Libraries
Basic OS Drivers
Up to 12
Sensor Components
Up to 68 GPIO
16-bit SAR ADC I2 12-bit DAC LVI
C
USB
Device
Bootloader
128 KB Flash 12 KB SRAM
USB ROM
freescale .com/medical 47

Features:
Home Portable Medical
• S08 core delivering a 48 MHz core speed
and 24 MHz bus speed
• Up to 128 KB flash and 12 KB SRAM
• Low-power stop 2 current: 450nA
(12 KB of active SRAM)
• 2 x OPAMP—General purpose opamps
• 2 x TRIAMP—Transimpedance amplifiers
• 16-bit SAR analog-to-digital converter
(ADC) – high resolution ADC
• Analog comparator
• Internal voltage reference
• USB device controller
• 2 x serial peripheral interface (SPI),
2 x serial communications interface (SCI)
and 1 x I2C MCF51MM: Flexis 32-bit
ColdFire V1 MCUs
The MCF51MM256/128 provides ultralow-power
operation, USB connectivity,
graphic display support and unparalleled
measurement accuracy, all in a single 32-bit
MCU, allowing designers to create more
fully featured products at lower cost. The
MCF51MM256/128 is ideal for medical
applications or other applications requiring a
significant amount of precision analog such as
instrumentation and industrial control.
The MCF51MM256/128 is part of the
Freescale Flexis MCU series.
Features:
• ColdFire V1 core delivering a 50 MHz core
speed and 25 MHz bus speed
• Up to 256 KB flash and 32 KB SRAM
• Low-power stop 2 current: 500 nA
(32 KB of active SRAM)
• 2 x general purpose opamps
• 2 x transimpedance amplifiers
• 16-bit SAR high resolution analog-to-digital
converter (ADC)
• Analog Comparator with 5-bit digital-toanalog
converter (DAC)
Figure 8-6: MCF51MM256 Block Diagram
Figure 9-9: MCF51MM256 Block Diagram
2x OPAMP
2x TRIAMP
PDB
MCG
Figure 8-7: Kinetis K50 Family Block Diagram
Figure 9-8 Kinetis K50 Family
Debug
Interfaces
Interrupt
Controller
Security
and Integrity
Cyclic
Redundancy
Check (CRC)
Random
Number
Generator
Cryptographic
Acceleration
Unit (CAU)
Core
ARM ® Cortex-M4
72/100 MHz
Standard Feature
System Memories
Internal and
External
Watchdogs
Memory
Protection Unit
(MPU)
Xtrinsic
Low-Power
Touch-Sensing
Interface
Segment
LCD Controller
48 Medical Applications User Guide
DSP
Analog
16-bit
ADC
PGA
Analog
Comparator
6-bit
DAC
12-bit
DAC
Voltage
Reference
OPAMP
TRIAMP
VREF TOD
16-bit SAR ADC I2 12-bit DAC LVI
C
PRACMP CMT
2 x 4-ch. TPM with PWM 2 x SPI
2 x KBI 2 x SCI
32-bit V1 ColdFire 50 MHz Core with MAC
DMA
Low-Leakage
Wake-Up Unit
Timers
FlexTimer
Carrier
Modulator
Transmitter
Programmable
Delay Block
Periodic
Interrupt
Timer
Low-Power
Timer
Independent
Real-Time
Clock (IRTC)
IEEE ® 1588
Timer
Optional Feature
Program
Flash
(128 to 512 KB)
FlexMemory
(32 to 256 KB)
(2 to 4 KB EE)
Serial
Programming
Interface
(EZPort)
SRAM
(32 to 128 KB)
External
Bus Interface
(FlexBus)
Clocks
Phase-Locked
Loop
Frequency-
Locked Loop
Low/High-
Frequency
Oscillators
Internal
Reference
Clocks
Communication Interfaces HMI
I 2 C
UART
(ISO 7816)
SPI
IEEE 1588
Ethernet MAC
I 2 S
Secure
Digital Host
Controller
(SDHC)
USB OTG
(LS/FS)
USB Charger
Detect (DCD)
USB Voltage
Regulator
Up to 68 GPIO/
16 RGPIO
MiniBus External
USB
Device/Host/
OTG
Bootloader
256 KB 32 KB SRAM
USB ROM
GPIO

• Internal voltage reference
• USB – device/host/on-the-go controller
• 2 x serial peripheral interface (SPI),
2 x serial communication interface (SCI)
and 1 x I2C • Mini FlexBus (external bus interface EBI)
K50 Measurement MCUs
The K50 MCU family is pin, peripheral and
software compatible with other Kinetis MCUs
and provides designers with an analog
measurement engine consisting of integrated
operational and transimpedance amplifiers
and high-resolution ADC and DAC modules.
The family also features IEEE 1588 Ethernet
and hardware encryption, full-speed USB
2.0 On-The-Go with device charger detect
capability and a flexible low-power segment
LCD controller with support for up to 320
segments. Devices start from 128 KB of flash
in 64-pin QFN packages extending up to 512
KB in a 144-pin MAPBGA package.
Key Features
Kinetis K50 MCU features and peripherals in
the integrated measurement engine:
• Ultra-low-power operation
• 2x OPAMP
• 2x TRIAMP
• 2x 12-bit DAC
• 2x 16-bit SAR ADC, up to 31 channels with
programmable gain amplifiers (PGA)
• Programmable Delay Block (PDB)
• I2C • USB connectivity
• ARM Cortex-M4 core with DSP (Digital
Signal Processor) instructions
Home Portable Medical
freescale .com/medical 49

Hearing Aids
9.1
Introduction
A hearing aid is a small electronic device worn in or behind the ear that
amplifies incoming sounds. A hearing aid can help people with hearing
loss hear better in both quiet and noisy situations. Low power, digital
and adaptative filtering are key design elements for battery-operated
hearing aids to reduce the environmental noise so that only the desired
signals are amplified and sent to the speaker. An inertial sensor can be
used for gesture recognition in high-end units where a shake motion
could turn the hearing aid on or change volume.
50 Medical Applications User Guide

9.2
Microphone Amplifier
The microphone and amplifier are used to
convert sound into electrical signals. The
microphone is a transducer that converts
vibrations in the air to electrical signals.
The microphone can be connected to a
preamplifier to couple the impedances and
normalize the audio levels. The preamplifier
output is connected to the amplifier input to
condition the signal-in voltage levels used by
the analog-to-digital converter (ADC).
The ADC converter transforms the continuous
audio signal into digital samples to be
processed and filtered by a digital signal
processor (DSP).
9.3
Li-Ion Battery Charger
Circuit
Because this device is designed to be worn
in or behind the ear, the power source must
be batteries. Using rechargeable batteries
eliminates the need to replace or purchase
batteries.
MC13883: Integrated Charger,
USB On-the-Go Transceiver and
Carkit Interface
The Freescale MC13883 is a monolithic
integration of a lithium ion battery charger with
a CEA-936 carkit with interfacing support and
a USB OTG transceiver.
Key Features
• Li-ion battery charging through a USB
connector
• Multiple charger modes and configurations
supported
• Overvoltage protection for shielding
products from faulty (high-voltage) charging
sources
• Trickle pre-charge of deeply discharged
batteries
• Reverse path capability allows power to be
sourced to the VBUS pin from the battery
and can be used to support phone-powered
devices through the USB connector
• Charge indicator LED driver
Figure 9-1: Hearing Aid General Block Diagram
Hearing Aid
AC Mains
Li-Ion Battery
Charger Circuit
Microphone
Amplifier
Power
Management
Voltage
Regulation
Freescale Technology Optional
Figure 9-2: Signal Acquisition Block Diagram
Figure 8-2: Signal Acquisition Block Diagram
Pre-Amplifier
Home Portable Medical
Non-Volatile
Memory
DSP/DSC
Loudspeaker
Class D Amplifier
Wireless
Comm
Keypad
Inertial
Sensor
freescale .com/medical 51
Amplifier
SPI/I 2 C
High-Speed
Analog-to-Digitial
Converter
Microphone Digital Signal Processor
(DSP)
Figure 9-3: MC13883 Block Diagram
Figure 8-3: MC13883 Block Diagram
10-bit ADC
Battery Monitoring
Li-Ion Battery Charger,
USB Charging,
Overvoltage Protection
MC13883
SPI/I 2 C
Interface
USB OTG
Transceiver
and Car Kit
Interface
n
BB Processor

Home Portable Medical
• USB 2.0 OTG transceiver with regulated
supplies, ID detection and interrupt
generation
• Communication and audio control follows
the protocol defined by the CEA-936 carkit
specification
• Serial peripheral interface (SPI) and
inter-integrated circuit (I2C) support for
flexible processor interfacing and system
integration
• 40-pin QFN package, 6 mm x 6 mm
9.4
Class D Amplifier
For applications in audio amplification
there are several available technologies.
Analog Class AB has been the predominant
technology for these applications, however,
the industry uses Class D amplifier
technology. Class D amplification offers many
advantages over other technologies. Pulse
width modulation is often used to improve
power performance. This results in lower heat
dissipation which allows more audio channels
and higher wattage in smaller form factors.
Freescale DSP5680x devices offer a combination
of peripherals and software to enable Class D
amplifiers to work at peak performance.
DSP5680x Architecture
The architecture of the DSP5680x device
captures the best of the DSP and MCU
worlds. Its key features include:
• Advanced pulse width modulation
• Dual analog-to-digital converters
• Programmable 16-bit timers
• 8 MHz crystal oscillator and PLL with
integrated pre- and post-scalars
• On-board power conversion and
management
• JTAG/OnCE debug programming interface
Figure 8-4: 9-4: General General Diagram Diagram of Class of Class D Amplifier D Amplifier Implementation Implementation
PWM signals
Digital Signal Processor
(DSP)
Figure 9-5: Principle of PWM Modulation
Figure 8-5: Principle of PWM Modulation
Amplitude
Amplitude
Amplitude
Amplifier H-bridge
52 Medical Applications User Guide
f vin
V in
V mod
V in
V mod
n
Low Pass
Figure 9-6: DSP Audio Application
Figure 8-6: DSP Audio Application
Input
Audio
Channels
Digital
Input
Audio
Codec
DSP56F80x
SPI GPIO
SPI
GPIO
PWM
f mod
Buttons
Display
Power
Stage
Time
Time
Frequency
Speaker
Low Pass
Filter

9.5
Digital Signal Processor
The digital signal processor (DSP) performs
the signal’s digital filtering. The audio signal
samples taken from the ADC are stored in
memory. A filter algorithm is applied to the
sampled signal.
A DSC such as Freescale’s MC56F8006 can
take the place of an amplifier, ADC and PWM/
timers. See Figure 9-7. The advantages to
replacing these discrete devices with one DSC
include board real estate savings (critical for
small hearing aids), increased reliability by
reducing the number of failure points and a
reduced cost.
The Freescale MC56F8006 DSC provides the
following features:
• 16-bit 56800E core
• Programmable gain amplifier connected to
ADC inputs
• Dual 12-bit ADC
• Six-channel, 15-bit PWM
For wireless communication, power
management, keypad and speaker
implementation, see Chapter 3 Introduction.
MC56F800x: MC56F8006 and
MCF56F8002 Digital Signal
Controllers
Key features of these DSCs include:
• Single-cycle 16 × 16-bit parallel multiplieraccumulator
(MAC)
• Four 36-bit accumulators including
extension bits
• Two 2x-16x programmable gain amplifiers
(PGAs)
• Three analog comparators
• Two 12-bit ADCs
• Six output PWMs with programmable fault
capability
• Two 16-bit timers, one 16-bit periodic
interval timer and a programmable delay
timer
• Ultra-low-power operation (nine different
power modes)
Home Portable Medical
Figure 9-7: Simplified Application Using Digital Signal Controller
Figure 8-7: Simplified Application Using Digital Signal Controller
Microphone
Digital Signal Controller
Pre-Amplifier Amplifier
Embedded
Analog-to-Digital
Embedded
Timers
n
Pre-Amplifier
Converter
(PWN function)
PWN
signals
Figure 9-8: MC56F800x Block Diagram
Figure 8-8: MC56F800x Block Diagram
6 KB
8 KB
Memory
Options
Three Analog
Comparators
Two 2x-16x
Wideband PGAs
High-Speed SCI
System Clock Control
(COSC, ROSC, PLL)
Two 12-bit
ADCs
2 KB SRAM
Application Notes
• Static Serial Bootloader for
MC56F800x/801x/802x/803x (document
AN3814)
freescale .com/medical 53
Flash
Power
SuperVisor
16-bit Periodic
Interval Timer
Programmable
Delay Block (PDB)
Six Output PWM
Voltage
Regulators
Interrupt
Controller
H-Bridge
Two 16-bit Timers
SPI PC COP
56800E Core/32MIPS
System Integration
Module (SIM)
Peripherals Flash RAM Core Plus Features
Speaker

Home Portable Medical
Table 9-1 Freescale Technologies for Home Portable Medical
Device Description Key Features Alternate Options
Blood Glucose Monitor
i.MX28x ARM9TM Applications Processor 454 MHz ARM9 core, power management, LCD controller, touch screen, DDR2/mDDR/
NAND, Ethernet, USB PHY x2,

Diagnostic and Therapy Devices
10.1
Introduction
Reliability and accuracy are key considerations for diagnostics and
therapy devices. These devices are used in critical situations when
physiological events need to be recognized quickly and addressed
appropriately. These medical devices need a processing core that is
powerful enough to acquire, process and interpret several parameters
at once.
A full spectrum of 32-bit processors (Vybrid, Kinetis, ColdFire,
i.MX and Power Architecture technology) offers performance and
integration. Integrated USB and Ethernet drivers facilitate convenient
data transfer from a device to a PC for processing or long-term
storage. LCD interfaces common across ARM-based product
portfolios (Vybrid, Kinetis and the i.MX family) provide clinicians and
patients a meaningful way to visualize clinical data in real time. The
i.MX53 processor, in particular, is being designed into several patient
monitoring applications.
Diagnostic and therapeutic medical devices can be positioned for
both the home and clinical market. Freescale’s controller continuum
enables development on an 8-bit platform for simple home devices,
which can then be upgraded to 32-bit platforms as new application
needs arise for the clinical market. The controller continuum serves
as a powerful resource for building fully integrated, scalable medical
solutions for the home or the clinic.
freescale .com/medical 55

Diagnostic and Therapy Devices
10.2
Electrocardiograph and
Portable ECG
An electrocardiogram (ECG or EKG) is a
graph produced by an electrocardiograph
that records the electrical activity of the heart
over time. This allows health care providers to
diagnose a wide range of heart conditions.
A portable ECG is a device which plots the
electrical activity generated in the heart
against time. It is the test most used to
measure the functionality and pathologies of
the heart, such as arrhythmias. The function
of the electrocardiograph is based on the
electrical activity of heart cells due to the
depolarization that contracts the heart and
creates heartbeats. The obtained signal is
called a QRS complex.
10.3
QRS Complex
A typical ECG period consists of P, Q, R,
S and T waves (see Chapter 5, page 32,
Heart Rate Monitor). Each wave represents
something and helps in diagnosis. Sometimes
the signal is represented as QRS complex
and P and T waves. The QRS complex is
separated from the signal to receive specific
information.
To obtain the QRS complex, a digital highpass
filter is implemented to remove noise
and drift. A differential is used to emphasize R
and smooth T, square the signal and integrate
it to smooth noise. This is done over a short
period so as not to smooth the R wave.
The beating heart generates an electric
signal that helps to diagnose or examine
the heart. This signal can be represented as
a vector quantity. Therefore, the location of
the electrical signal that is being detected
needs to be known. To get a typical signal it
is necessary to place three electrodes: one
on the patient’s left arm, the other on the right
arm, and the ground electrode on the patient’s
stomach or left leg.
Figure 10-1: Electrocardiograph Block Diagram
Electrocardiograph (ECG)
Precordial
RA LA
FPO
JTAG
Use updated version
RL LL
with CR Touch
added. Currently in
progress with Alle.
Inverted
Common
Mode Voltage
Feedback
Freescale Technology
Electrical
Protection
and Mux
Power
Management
Optional
Display Driver
Keypad or
Touch Screen
Y(n)
56 Medical Applications User Guide
In
Amp
Portable Figure 10-2: ECG Block Portable Diagram ECG Block Diagram
Electrodes
Keypad
Signal
Conditioning
USB and/or
Ethernet
Wireless
Comm
Freescale Technology Optional
ADC
ADC
Power
Management
MCU
12-Lead EKG System
MCU/MPU/DSC
Wireless
Comm
USB and/or
Ethernet
SPI/I 2 C
PWM
Display with
Touch Screen
Non-Volatile
Memory
Figure
Figure
9-3:
10-3:
Digital
Digital
Signal
Signal
Processing
Processing
to Obtain
to Obtain
the QRS
the
Complex
QRS Complex
X(n)
Raw ECG
LPF
HPF
Q
R
S
Differentiate
Integrate
Square
Speaker/Piezo

10.4
Filtering ECG
The ECG has three common noise sources:
• Baseline wander
• Power line interference
• Muscle noise
The baseline wander is caused by electrode
impedance, respiration, body movements and
low- and high-frequency noise. This makes
it necessary to use a band-pass filter as
described in Chapter 5, Heart Rate Monitor. To
eliminate the low-frequency noise, a high-pass
filter with a cut-off frequency of 0.67 Hz is used,
because this corresponds to the slowest heart
rate of around 40 beats per minute. However,
because this is not an absolute data point, it
is better to use a cut-off frequency of 0.5 Hz.
Figure 10-5 shows a basic implementation
circuit that detects the electrical currents
through the electrodes.
10.5
Electrodes Interface
The amplitude of the signals detected by
the electrodes is too small. The signals are
connected to operational amplifier inputs
through series limiter resistors (typically 100K),
and amplified a little. The feedback network
helps to stabilize the system at the beginning
of the capture time, reducing fluctuations.
Finally, the signal is sent to an active low-pass
filter. The filter eliminates the high-frequency
noise which might be induced by the AC line.
Other noise sources such as respiration and
muscular movement (low-frequency noise) are
filtered using a high-pass filter. These noise
sources require a band-pass filter and not just
a low-pass filter.
AN4323: Freescale’s Solutions for
Electrocardiograph and Heart Rate
Monitor Applications
This application note describes how to use
the MED-EKG development board, a highly
efficient board that can be connected to
the Freescale Tower System to obtain an
electrocardiogram signal and measure
heart rate.
Figure 10-4: Einthoven Triangle
Figure 9-4: Einthoven Triangle
Right
Arm
Diagnostic and Therapy Devices
freescale .com/medical 57
–
-
Y
II III
Figure 10-5: Electrodes Connection Circuit and Signal Conditioning
Figure 9-5: Electrodes Connection Circuit and Signal Conditioning
Right Hand
Right Leg Left Leg
Left Hand
+
Analog
Frond End
Electrodes
Multiplexer
and Isolator
Figure 10-6: ECG Analog Front End
Figure 9-6: ECG Analog Front End
Left
Electrode
Right
Electrode
100K
100K
Differential Amplifier
+
Left
Leg
I
+
Instrumentation
Amplifier
Feedback Network
–
Left
Arm
X
Band Pass
Filter
Filter Network
To MCU
ADC input
Output

Diagnostic and Therapy Devices
The application is implemented using
either the MK53N512, MC9S08MM128 or
MCF51MM256 MCUs.
K50 Measurement MCUs
The K50 MCU family is pin, peripheral and
software compatible with other Kinetis MCUs
and provides designers with an analog
measurement engine consisting of integrated
operational and transimpedance amplifiers
and high-resolution ADC and DAC modules.
The family also features IEEE 1588 Ethernet
and hardware encryption, full-speed USB
2.0 On-The-Go with device charger detect
capability and a flexible low-power segment
LCD controller with support for up to 320
segments. Devices start from 128 KB of flash
in 64-pin QFN packages extending up to 512
KB in a 144-pin MAPBGA package.
Key Features
Kinetis K50 MCU features and peripherals in
the integrated measurement engine:
• Ultra-low-power operation
• 2x OPAMP
• 2x TRIAMP
• 2x 12-bit DAC
• 2x 16-bit SAR ADC, up to 31 channels with
programmable gain amplifiers (PGA)
• Programmable Delay Block (PDB)
• I2C • USB connectivity
• ARM Cortex-M4 core with DSP instructions
MCF51MM: Flexis 32-bit
ColdFire V1 MCUs
The MCF51MM256/128 provides ultralow-power
operation, USB connectivity,
graphic display support and unparalleled
measurement accuracy, all in a single 32-bit
MCU, allowing designers to create more
fully featured products at lower cost. The
MCF51MM256/128 is ideal for medical
applications or other applications requiring a
significant amount of precision analog such as
instrumentation and industrial control.
The MCF51MM256/128 is part of the
Freescale Flexis MCU series.
Figure
Figure 9-7:
10-7:
MED
MED
EKG
EKG
Block
Block
Diagram
Diagram
Instrumentation
Amplifier
Band Pass Filter
Operational
Amplifier
Electrodes
• On-board
• External
Low Pass Filter
Notch Filter
Low Pass Filter
DSC
MC56F8006
MCU Internal Configuration
(Instrumentation Amplifier)
Freescale Technology User Selectable
Low Pass Filter
High Pass Filter
58 Medical Applications User Guide
PWM
ADC
TriAmp
TriAmp
Operational
Amplifier
OpAmp
Figure 10-8: Kinetis K50 Family Block Diagram
Figure 9-8 Kinetis K50 Family
Security
and Integrity
Cyclic
Redundancy
Check (CRC)
Random
Number
Generator
Cryptographic
Acceleration
Unit (CAU)
Core
ARM ® Cortex-M4
72/100 MHz
Debug
Interfaces
Interrupt
Controller
Standard Feature
DSP
Analog
16-bit
ADC
PGA
Analog
Comparator
6-bit
DAC
12-bit
DAC
Voltage
Reference
OPAMP
TRIAMP
Timers
I 2 C
ADC
System Memories
Internal and
External
Watchdogs
Memory
Protection Unit
(MPU)
DMA
Low-Leakage
Wake-Up Unit
FlexTimer
Carrier
Modulator
Transmitter
Programmable
Delay Block
Periodic
Interrupt
Timer
Low-Power
Timer
Independent
Real-Time
Clock (IRTC)
IEEE ® 1588
Timer
Optional Feature
Program
Flash
(128 to 512 KB)
FlexMemory
(32 to 256 KB)
(2 to 4 KB EE)
Serial
Programming
Interface
(EZPort)
MCU
MK53N512
or
MCF51MM256
or
MC9S08MM128
DAC ADC
Band Pass Filter
SRAM
(32 to 128 KB)
External
Bus Interface
(FlexBus)
Host PC
with GUI
USB
Internal
OpAmp
Clocks
Phase-Locked
Loop
Frequency-
Locked Loop
Low/High-
Frequency
Oscillators
Internal
Reference
Clocks
Communication Interfaces HMI
I 2 C
UART
(ISO 7816)
SPI
IEEE 1588
Ethernet MAC
I 2 S
Secure
Digital Host
Controller
(SDHC)
USB OTG
(LS/FS)
USB Charger
Detect (DCD)
USB Voltage
Regulator
GPIO
Xtrinsic
Low-Power
Touch-Sensing
Interface
Segment
LCD Controller

Features:
• ColdFire V1 core delivering a 50 MHz core
speed and 25 MHz bus speed
• Up to 256 KB flash and 32 KB SRAM
• Low-power stop 2 current: 500 nA
(32 KB of active SRAM)
• 2 x general purpose opamps
• 2 x transimpedance amplifiers
• 16-bit SAR high resolution analog-to-digital
converter (ADC)
• Analog Comparator with 5-bit digital-toanalog
converter (DAC)
• Internal voltage reference
• USB – device/host/on-the-go controller
• 2 x serial peripheral interface (SPI),
2 x serial communication interface (SCI)
and 1 x I2C • Mini FlexBus (external bus interface EBI)
• Included in Freescale’s Product Longevity
Program
S08MM: Flexis 8-bit MCUs
The 9S08MM128/64/32 provides ultralow-power
operation, USB connectivity,
graphic display support and unparalleled
measurement accuracy, all in a single 8-bit
MCU, allowing device designers to create
more fully featured products at a lower cost.
It is ideal for applications requiring a
significant amount of precision analog.
The 9S08MM128/64/32 is part of Freescale’s
Flexis MCU series.
Features:
• S08 core delivering a 48 MHz core speed
and 24 MHz bus speed
• Up to 128 KB flash and 12 KB SRAM
• Low-power stop 2 current: 450nA
(12 KB of active SRAM)
• 2 x OPAMP- General purpose opamps
• 2 x TRIAMP- Transimpedance amplifiers
• 16-bit SAR analog-to-digital converter
(ADC) – high resolution ADC
• Analog comparator
• Internal voltage reference
• USB device controller
• 2 x serial peripheral interface (SPI),
2 x serial communications interface (SCI)
and 1 x I2C Figure 9-9: 10-9: MCF51MM256 Block Block Diagram Diagram
2x OPAMP
2x TRIAMP
PDB
MCG
MCF5227X: V2 MCU with a Touch
Screen, LCD Controller and USB
Key Features
• 8 KB configurable I/D cache
• 128 KB RAM
• Integrated LCD controller
• CSTN and TFT w/up to 800 x 600
(SVGA) resolution
• 8 x 12-bit ADC w/touch-screen controller
• Real touch screen controller
• USB 2.0 full-speed On-The-Go controller
• CAN 2.0B controller (FlexCAN)
VREF TOD
PRACMP CMT
2 x 4-ch. TPM with PWM 2 x SPI
2 x KBI 2 x SCI
32-bit V1 ColdFire 50 MHz Core with MAC
Diagnostic and Therapy Devices
Up to 68 GPIO/
16 RGPIO
16-bit SAR ADC I2 12-bit DAC LVI
C
MiniBus External
USB
Device/Host/
OTG
Bootloader
256 KB 32 KB SRAM
USB ROM
Figure
Figure
9-10:
10-10:
MC9S08MM128
MC9S08MM128
Block
Block
Diagram
Diagram
2x OPAMP
2x TRIAMP
PDB
MCG
VREF TOD
16-bit SAR ADC I2 12-bit DAC LVI
C
PRACMP CMT
2 x 4-ch. TPM with PWM 2 x SCI
2 x KBI 2 x SPI
8-bit 9S08 48 MHz Core
Up to 68 GPIO
USB
Device
Bootloader
128 KB Flash 12 KB SRAM
USB ROM
• Three UARTs
• DMA serial peripheral interface (DSPI)
• I2C bus interface
• Synchronous serial interface (SSI)
• 4-ch., 32-bit timers with DMA support
• Real-time clock
• 16-ch. DMA controller
• 16-bit DDR /32-bit SDR SDRAM controller
• Up to 55 general-purpose I/O
• System integration (PLL, SW watchdog)
• 1.5V core, 1.8V/2.5V/3.3V bus I/O
freescale .com/medical 59

Diagnostic and Therapy Devices
Power management and wireless
communication blocks are explained in
Chapter 3, Telehealth Systems.
10.6
Display Driver and Touch
Screen Controller
An LCD screen shows graphically the heart’s
electrical signals and allows for a diagnosis of
any cardiac anomalies or other problems. A
touch screen offers developers an easy way to
enhance their applications with touch-based
user interfaces.
Connecting screens to the MCF5227x is
shown in Figure 10-12.
For more information about these
connections, see the MCF5227x reference
manual and application notes about touch
screens and LCD memory, available at
freescale.com.
10.7
Enhanced Multiply-
Accumulate (eMAC)
Module
A ColdFire or Kinetis MCU such as the
MCF5227x, MCF51MM256 or MK53N512 can
process the digital signals of the heartbeat,
avoiding the need to use a separate DSP
or DSC.
The eMAC design provides a set of DSP
operations that can improve the performance
of embedded code while supporting the
integer multiply instructions of the baseline
ColdFire architecture.
The ColdFire family supports two MAC
implementations with different performance
levels and capabilities. The original MAC features
a three-stage execution pipeline optimized for
16-bit operands with a 16 x 16 multiply array
and a single 32-bit accumulator. The eMAC
features a four-stage pipeline optimized for
32-bit operands with a fully pipelined 32 × 32
multiply array and four 48-bit accumulators.
Figure 9-11: 10-11: MCF522x MCF522x Family Family Block Block Diagram Diagram
12-bit color
16-bit color
LCD
Controller
Figure 10-13: Typical DSP Chain
Figure 9-13: Typical DSP Chain
Analog
Low-Pass
Filter
BDM PLL CCM GPIO JTAG
USB OTG EPORT SSI
8 KB Cache
Sample
and Hold
ADC
60 Medical Applications User Guide
ASP
Digital
Filters
SW/HW on ColdFire
INTC I 2 C
LCDC RTC DSPI
32-bit
4 DMA Timers
EMAC
2-ch.
4 PWM
ColdFire V2
Core
XBS FlexCAN
2 PIT 3 UART
DC/PWM
DC/PWM
128 KB SRAM
System
Integration
Debugging/Interface Peripherals Flash RAM Core Plus Feature
Figure 9-12: 10-12: Screen Screen Connection Connection on MCF5227x on MCF5227x
MPU
Red bus
Green bus
Blue bus
6
6
6
Horizontal Sync
Vertical Sync
Pixel Clock
Output Enable
I2C/ADC Channel
Touch Screen Controller
RGB Screen
with Touch Screen
Analog
Low-Pass
Filter
Analog
Low-Pass
Filter

The eMAC improvements target three
primary areas:
• Improved performance of 32 × 32 multiply
operation
• Addition of three more accumulators to
minimize MAC pipeline stalls caused by
exchanges between the accumulator and
the pipeline’s general-purpose registers
• A 48-bit accumulation data path to allow a
40-bit product plus eight extension bits to
increase the dynamic number range when
implementing signal processing algorithms
The logic required to support this functionality
is contained in a MAC module (Figure 10-14).
Figure 10-15 is a typical implementation of
digital signal processing using ColdFire.
Freescale provides two documents describing
DSP algorithms functionality:
- ColdFire DSP Library Reference Manual Rev 0.4
- Digital Signal Processing Libraries Using the
ColdFire eMAC and MAC
- Fast-Fourier transform (FFT)
- Finite impulse filter (FIR)
- Infinite impulse filter (IIR)
ColdFire MPUs such as the MCF5227x can
perform digital signal processing using the
enhanced multiply-accumulate module.
This allows medical applications such as an
electrocardiograph to perform heart signal
filtering more efficiently.
10.8
USB Connection
The USB connection allows the EGC to
communicate with other devices such as
hospital servers, remote monitoring systems
and computers. This can be implemented
using the USB On-the-Go module in the
MCF5227x, or in the MK20, MK40, MK50 or
MK60 family members.
Shift 0,1,-1
Diagnostic and Therapy Devices
Figure 9-14: 10-14: Multiply-Accumulate Functionality Functionality Diagram Diagram
Operand Y
Figure 9-15: 10-15: DSP DSP Library Library Structure Structure
freescale .com/medical 61
X
+/-
Accumulator(s)
eMAC Library
Operand X
FFT FIR IIR
FFT 16 Bits FIR 16 Bits IIR 16 Bits
MAC MAC MAC
eMAC eMAC eMAC
FFT 32 Bits FIR 32 Bits IIR 32 Bits
MAC MAC MAC
eMAC eMAC eMAC
Figure 9-16: 10-16: Hardware Hardware Configuration Configuration in Host in Mode Host Mode
MCU with
USB module
D-
D+
Pull-down resistors
Figure 9-17: 10-17: Hardware Configuration in Device in Device Mode Mode
MCU with
USB module
Pull-up resistor
D-
D+
VDD
VDD
USB power
VBUS D- D+ G
VBUS D- D+ G

Defibrillators
11.1
Automated External Defibrillator (AED)
An AED is a portable device used to restore normal heart rhythm to
patients in cardiac arrest by delivering an electrical shock to a patient
through the chest wall. Cardiac arrest is an abrupt loss of heart
function. This medical emergency occurs mainly because of ventricular
fibrillation.
Ventricular fibrillation is a condition where there is an uncoordinated
contraction of the ventricles in the heart, making them tremble rather
than contract properly. The urgency of ventricular fibrillation requires
that the heart must be defibrillated quickly, as a victim’s chance of
surviving drops by seven to 10 percent for every minute a normal
heartbeat is not restored.
An MCU or MPU calculates whether defibrillation is needed and a
recorded voice indicates whether to press the shock button on the
AED. This shock momentarily stuns the heart and stops all activity,
giving the heart an opportunity to resume beating effectively.
The charge is generated by high-voltage generation circuits from
energy stored in a capacitor bank in the control box. The capacitor
bank can hold up to 7 kV of electricity. The shock delivered from this
system can be anywhere from 30 to 400 joules.
62 Medical Applications User Guide

11.2
Circuit for Capacitive
Discharge Defibrillators
In Figure 11-2, a step-up transformer (T2)
drives a half-wave rectifier and charges
the capacitor (C1). The voltage where C1
is charged is determined by a variable
autotransformer (T1) in the primary circuit.
A series resistor (R1) limits the charging
current to protect the circuit components, and
determines the time constant Tao (T = R x C).
Five times the time constant for the circuit is
required to reach 99 percent of a full charge.
The time constant must be less than two
seconds to allow a complete charge in less
than 10 seconds.
11.3
Circuit for Rectangular-
Wave Defibrillators
In a rectangular-wave defibrillator, the
capacitor is discharged through the patient
by turning on a series of silicon-controlled
rectifiers (SCR). When sufficient energy has
been delivered to the patient, a shunt SCR
short circuits the capacitor and terminates
the pulse. This eliminates the long discharge
tail of the waveform. The output may be
controlled by varying either the voltage on the
capacitor or the duration of discharge. Figure
11-3 shows a general diagram of circuit
implementation.
Bipolar defibrillators are more efficient
because they need less energy while
providing the same results as unipolar
defibrillators. A bipolar defibrillator needs just
120 J to discharge. It has the same efficiency
as the 200 J of discharge used by a unipolar
defibrillator.
An ECG unit must be included in the
defibrillator’s system to monitor heart
activity and to control the moment when
the discharge can be applied to the patient.
The electrodes perform both functions,
capturing the patient’s ECG and delivering
a high current.
Defibrillator
Defibrillator
Figure 11-1: Defibrillators General Block Diagram
Syncronization
Circuit
Syncronization
Circuit
Electrodes
Electrodes
Discharge
Circuit
Discharge
Circuit
ECG
Amplifier
ECG
Amplifier
Freescale Technology
Freescale Technology
Optional
MCU/MPU
Diagnostic and Therapy Devices
Signal
Conditioning
Signal
Conditioning
Unipolar Bipolar
freescale .com/medical 63
Electrical Isolation
Electrical Isolation
Display
Optional
Display
MCU/MPU
Keypad or
Touch Screen
Keypad or
Touch Screen
USB
USB
Wireless
Comm
Wireless
Comm
Power
Management
Power
Management
Figure 10-2: Basic Circuit Diagram for a Capacitive Discharge Defibrillator
Figure 11-2: Basic Circuit Diagram for a Capacitive Discharge Defibrillator
Figure 10-3: 11-3: Block Block Diagram Diagram for for a Rectangular-Wave a Rectangular-Wave Defibrillator Defibrillator
Figure 10-4: Unipolar Defibrillator Waveform
Volts
2500
2000
1500
1000
500
0
0
1
2 4 6 8 10
Time (ms)
12 14 16 18
Charge
Control A
Charge
Circuit A
Charge
Circuit B
Charge
Control B
Capacitor
Bank A
Capacitor
Bank B
Monitor
Circuit
Monitor
Circuit
Figure 11-4: Unipolar and Bipolar Defibrillator Waveforms
Figure 10-5: Bipolar Defibrillator Waveform
Volts
2500
2000
1500
1000
500
0
0
1
5 10 15 20 25
Time (ms)
30 35 40 45

Ventilation and Spirometry
12.1
Introduction
A ventilator is a machine designed to mechanically move air in and
out of the lungs to intermittently or continuously assist or control
pulmonary ventilation. This apparatus is principally used in intensive
therapy to help improve the patient’s breathing by regulating the
flow of gas in the lungs. The most common indices of the ventilation
apparatus are the absolute volume and changes of volume of the gas
space in the lungs achieved during a few breathing maneuvers. The
ventilator is constantly monitored and adjusted to maintain appropriate
arterial pH and PaO2.
This system requires a set of sensors for pressure, volume and flow.
The information from the sensors modulates the operations in the
MCU/MPU. This MCU/MPU receives information from the airways,
lungs and chest wall through the sensors and decides how the
ventilator pump responds.
64 Medical Applications User Guide

12.2
System Sensors
Figure 12-1: Ventilation/Respiration General Block Diagram
Ventilation/Respiration
The signal that shows lung volume is a differential
AIR O2 signal, but this is not the signal measured
directly from the lungs. To get this signal, it is
PWR
PWR
necessary to transduce the pressure to voltage.
This is done by using a pneumotachometer
that contains a pressure sensor.
PWF
Sensor
Nebulizer
Accumulator/
Compressor
Blender Display
Freescale provides a variety of sensors that
Pressure
Sensor
Volume
Wireless
Comm
use integrated circuits for signal conditioning.
This is an advantage because external
components are not necessary. However, it
Sensor
Flow
Sensor
Power
AMP
MCU/MPU
USB
is necessary to check the resolution of the
sensor and the ADC. If the resolution of the
Management
ADC is greater than the sensor, amplifying
the signal is recommended. Some sensors
provide differential outputs for when it is
Alarm
Keypad or
Touch Screen
necessary to pass the signal through an
instrument amplifier. The sensor used is a
differential pressure sensor that can accept
two sources of pressure simultaneously. The
output is proportional to the difference of
the two sources. It is important to mention
Freescale Technology Optional
that the normal pipeline gas source of a
Ventilation/Respiration
hospital is 50 PSI, a measurement that
Figure 12-2: Spirometer
can be taken by Freescale’s pressure Figure 11-2: Spirometer
sensors. Freescale pressure sensors include
AIR O2 MPX2300DT1, MPX2301DT1, MPXC2011DT1,
PWR
PWR
MPXC2012DT1, MPX2050 and MPX5050.
12.3
PWF
Sensor
MPX2300DT1
Accumulator/
Nebulizer MPX2301DT1
Compressor
MPXC2011DT1
Blender Display
Spirometer
Spirometers measure static pulmonary
Pressure
Sensor
Volume
MPXC2012DT1
MPX5050
MPX2050
Wireless
Comm
volumes, except the functional residual
capacity (FRC) and total pulmonary capacity
Sensor
Flow
Sensor
AMP
Amplification
MCU/MPU
USB
(TPC). The measurement is done after a
Power
Circuit
maximum inspiration that requires the patient
to expel the entire volume of air that he or she
Management
can. The results are interpreted and compared
with the values for age, height, sex and race
of the patient. Due to variations among normal
Alarm
Keypad or
Touch Screen
individuals, normal values can fall between 80
to 120 percent of the expected volume. Figure
12-2 illustrates how to configure a spirometer
using a pressure sensor. The next two figures
observe the different volumes of lungs.
Freescale Technology Optional
Lung volume measurements include:
• Tidal volume (TV)—The amount of gas
inspired or expired with each breath (500 ml)
Diagnostic and Therapy Devices
freescale .com/medical 65

Diagnostic and Therapy Devices
• Inspiratory reserve volume (IRV)—Maximum
amount of additional air that can be inspired
at the end of a normal inspiration (2500 ml)
• Expiratory reserve volume (ERV)—The
maximum volume of additional air that can
be expired at the end of a normal expiration
(1500 ml)
• Residual volume (RV)—The volume of air
remaining in the lungs after a maximum
expiration (1500 ml)
These measurements can be used in the
following equations to express lung capacities:
• Total lung capacity (TLC)
TLC=RV+IRV+TV+ERV (6000 ml)
• Vital capacity (VC)
VC=IRV+TV+ERV=TLC-RV (4500 ml)
• Functional residual capacity (FRC)
FRC=RV+ERV (3000 ml)
• Inspiratory capacity (IC)
IC=TV+IRV (3000 ml)
AN4325: Spirometer Demo
with Freescale MCUs
The contents of this application note show
how it is possible to use the Kinetis K50, Flexis
S08MM and Flexis MCF51MM MCUs along
with the Freescale Tower System to implement
a device capable to quantify human respiration
capacities, by measuring volumes and flow
rates. It uses the MED-SPI development
board, which is an analog front end designed
to enable the prototyping of spirometry
devices.
12.4
Graphic LCD MPU
Freescale offers the following devices that
generate graphics. These devices can be used
to illustrate lung volume.
• Kinetis MCUs
The Kinetis K70 MCU family includes
512KB-1MB of Flash memory, a single
precision floating point unit, and a Graphic
LCD Controller that supports color QVGA
displays as single chip or up to 24-bit SVGA
Figure 11-3: 12-3: MED SPI SPI Block Block Diagram
Mouthpiece
Freescale Technology
MPXV7025DP
(Pressure Sensor)
Figure 12-4: 11-4: Normal Spirometer
66 Medical Applications User Guide
8
7
6
5
4
3
2
1
0
Volume (L)
displays using external memory. Supported
by Freescale’s Portable Embedded GUI
(PEG) Library with simple WindowBuilder
interface for powerful GUI development.
• Vybrid Controller Solutions
Part of the Vybrid platform, the VF7xx
family of devices are dual heterogeneous
core SoCs meant for solutions that want
to concurrently run Linux ® or Android on
FFF
MCU
ADC MK53N512
or
MCF51MM256
or
MC9S08MM128
USB Host PC
with GUI
FEV 1
FVC
0 1 2
Time (sec)
3 4
the ARM ® Cortex-A class core and an
RTOS like MQX on the ARM ® Cortex-M
class core optimized power-performance
core with very high integration. The VF7xx
devices have been designed to replace at
least the MPU and the MCU products on a
system needing Rich HMI plus Real Time
control at the same time.

• i.MX Processors
The most versatile platform for multimedia
and display applications, Freescale ARMbased
i.MX processors deliver an optimal
balance of power, performance and
integration to enable next-generation smart
devices. i.MX solutions include processors
based on ARM9 , ARM11 , ARM ®
Cortex-A8 and ARM Cortex-A9 core
technologies, and are powering applications
across a rapidly growing number of
consumer, automotive and industrial
markets. Our solutions bring interactivity
to a whole new world of products.
12.5
Alarm System
An important part of this application is an
alarm that can indicate different patient
parameters such as exhaled volume or airway
pressure. The ventilation system must be able
to detect whether a breath has been taken.
The MCU measures changes in aspiratory
flow and pressure by using sensors. If no
inspiration is detected within a certain period
of time, the monitor sounds an alarm. The
conditions to be programmed depend on each
system. PWM cycles can be programmed to
sound the alarms. Sometimes, the ventilation
system uses different alarms for different
situations. For more information on the alarm
circuit, refer to Chapter 3, Telehealth Systems.
12.6
Air and Oxygen Blender
and Mix Control
The air and oxygen blender provides a precise
oxygen concentration by mixing air and
oxygen. The concentration may be adjusted
to any value from controlled air to 100 percent
oxygen. Internally, a proportioning valve mixes
the incoming air and oxygen as the oxygen
percentage dial is adjusted. Variation in line
pressure, flow or pressure requirements for
any attached device will not affect the oxygen
concentration.
Figure 11-5: 12-5: Normal Lung Lung Volume Volume
TLC
0
Diagnostic and Therapy Devices
freescale .com/medical 67
V T
ERV
IRV
FRC
Figure 12-6: Blender Configuration
Figure 11-8: Blender Configuration
PWR
Accumulator/
Compressor
IC
Time
AIR O2
PWR
Blender
MCU/MPU
VC
RV

Diagnostic and Therapy Devices
The preparation of an air and oxygen blender
generally consists of attaching a 50 PSI air
and oxygen source to the device. After the
source gases are attached, inlet pressures
may be checked on some blenders by
checking the pressure-attached pressure
gauge. After the inlet gases are attached and
the air and oxygen blender is well secured
to a stand or wall mount, it is ready for use.
The MCU uses a PWM to control the blender
electro valves through a motor control design.
Early ventilator designs relied on mechanical
blenders to provide premixed gas to a single
flow control valve. With the availability of
high-quality flow sensors and processing
capabilities, accurate mixing becomes
possible by using separate flow valves for
air and oxygen. Because air already contains
about 21 percent oxygen, the total flow
control command between the oxygen and air
valve is divided ratiometrically. For extreme
mix settings, the valve that supplies the minor
flow at low total flow requirements may fall
below the resolution limits that either flow
delivery or measurement can provide. An
accurate delivered mix depends on accurate
flow delivery, but if accurate and reliable
oxygen sensors are used, improved mix
accuracy may be possible by feeding back a
measured concentration for mix correction.
Then, if the patient needs more pressure, the
MCU activates the compressor.
For more information on how to build a
ventilator/respirator, download Ventilator/
Respirator Hardware and Software Design
Specification (document DRM127) from
freescale.com.
Kinetis K20 MCUs
The K20 MCU family is pin, peripheral and
software compatible with the K10 MCU family
and adds full-speed USB 2.0 On-The-Go
with device charge detect capability. Devices
start from 128 KB of flash in 80-pin LQFP
packages extending up to 512 KB in a 144pin
MAPBGA package with a rich suite of
analog, communication, timing and control
peripherals.
Figure Figure 11-9: 12-7: Kinetis Kinetis K20 K20 Block Block Diagram Diagram
Security
and Integrity
Cyclic
Redundancy
Check (CRC)
Core
ARM ® Cortex-M4
50/72/100/120 MHz
Debug
Interfaces
Interrupt
Controller
Standard Feature
Key Features
• ARM Cortex-M4 core with DSP, 100MHz
clock, single cycle MAC, and single
instruction multiple data (SIMD) extensions
• 128 KB - 512 KB flash. Fast access, high
reliability with four-level security protection
• Hardware touch-sensing interface with up
to 16 inputs. Operates in all low-power
modes (minimum current adder when
enabled). Hardware implementation avoids
software polling method. High sensitivity
level allows use of overlay surfaces up to
5 mm thick
System Memories
Internal and
External
Watchdogs
Memory
Protection Unit
(MPU)
Xtrinsic
Low-Power
Touch-Sensing
Interface
• Memory protection unit provides memory
protection for all masters on the cross bar
switch, increasing software reliability
• Cyclic redundancy check engine validates
memory contents and communication data,
increasing system reliability
68 Medical Applications User Guide
DSP
Floating Point
Unit (FPU)
Analog
16-bit
ADC
PGA
Analog
Comparator
6-bit
DAC
12-bit
DAC
Voltage
Reference
DMA
Low-Leakage
Wake-Up Unit
Timers
FlexTimer
Carrier
Modulator
Transmitter
Programmable
Delay Block
Periodic
Interrupt
Timers
Low-Power
Timer
Independent
Real-Time
Clock (RTC)
Optional Feature
Program Flash
(32 KB to 1 MB)
FlexMemory
(32 KB to 512 KB)
(2 to 16 KB EE)
Serial
Programming
Interface
(EzPort)
NAND Flash
Controller
SRAM
(8 KB to 128 KB)
External
Bus Interface
(FlexBus)
Cache
Clocks
Phase-Locked
Loop
Frequency-
Locked Loop
Low/High-
Frequency
Oscillators
Internal
Reference
Clocks
Communication Interfaces HMI
I 2 C
UART
(ISO 7816)
SPI
CAN
I 2 S
Secure
Digital Host
Controller
(SDHC)
USB On-the-Go
(LS/FS)
USB On-the-Go
(HS)
USB Device
Charger Detect
(DCD)
USB Voltage
Regulator
Table 12-1: MPXx2050 Packaging Information
Device Type Packing Options Case
MPX2050D Differential 344
MPC2050DP Differential, Dual Port 423 A
MPX2050GP Gauge 344B
MPX2050GSX Gauge Axial PC Mount 344F
GPIO

MPX230xDT1: High Volume
Pressure Sensor
Key Features
• Cost effectiveness
• Integrated temperature compensation and
calibration
• Ratiometric to supply voltage
• Polysulfone case material (ISO 10993)
• Provided in tape and reel
MPXx5050: –50 to 0 kPa and 0 to
50 kPa Integrated Silicon Pressure
Sensor, Temperature Compensated
and Calibrated
Key Features
• 2.5% maximum error over 0° to +85°C
• Ideally suited for MPU or MCU-based
systems
• Temperature compensated from over -40°C
to +125°C
• Patented silicon shear stress strain gauge
MPXx2050: 50 kPa Pressure Sensor
Key Features
• Temperature compensated over 0°C to +85°C
• Silicon shear stress strain gauge
• Available in rails or tape-in-reel shipping
options
• Ratiometric to supply voltage
• Differential and gauge options
• ±0.25% linearity
Integrated Peripherals
• Flexible 16-bit DDR/32-bit SDR SDRAM
memory controller
• Four channels, 32-bit timers with DMA
support
• 16 channels, DMA controller
• 16-bit DDR/32-bit SDR SDRAM controller
• 50 general-purpose I/O
Figure 12-8: Kinetis K50 Family Block Diagram
Figure 11-10: Kinetis K50 Family
Security
and Integrity
Cyclic
Redundancy
Check (CRC)
Random
Number
Generator
Cryptographic
Acceleration
Unit (CAU)
Core
ARM ® Cortex-M4
72/100 MHz
Debug
Interfaces
Interrupt
Controller
Standard Feature
MCF532X: ColdFire V3 MPU with
LCD Driver, Ethernet, USB and CAN
Key Features
• ColdFire V3 core delivering up to 211
(Dhrystone 2.1) MIPS at 240 MHz
• 32 KB RAM
• 16 KB I/D-cache
• Enhanced MAC module, manages DSP-like
instructions
Integrated Peripherals
• USB host/USB OTG
• 10/100 Fast Ethernet Controller (FEC)
• QSPI
• Serial synchronous interface (SSI)
• PWM—Four channels
• DMA—16 channels
• 16-bit DDR/32-bit SDR SDRAM controller
• Integrated SVGA LCD controller
Diagnostic and Therapy Devices
System Memories
Internal and
External
Watchdogs
Memory
Protection Unit
(MPU)
Xtrinsic
Low-Power
Touch-Sensing
Interface
Segment
LCD Controller
K50 Measurement MCUs
The K50 MCU family is pin, peripheral and
software compatible with other Kinetis MCUs
and provides designers with an analog
measurement engine consisting of integrated
operational and transimpedance amplifiers
and high-resolution ADC and DAC modules.
The family also features IEEE 1588 Ethernet
and hardware encryption, full-speed USB
2.0 On-The-Go with device charger detect
capability and a flexible low-power segment
LCD controller with support for up to 320
segments. Devices start from 128 KB of flash
in 64-pin QFN packages extending up to 512
KB in a 144-pin MAPBGA package.
freescale .com/medical 69
DSP
Analog
16-bit
ADC
PGA
Analog
Comparator
6-bit
DAC
12-bit
DAC
Voltage
Reference
OPAMP
TRIAMP
DMA
Low-Leakage
Wake-Up Unit
Timers
FlexTimer
Carrier
Modulator
Transmitter
Programmable
Delay Block
Periodic
Interrupt
Timer
Low-Power
Timer
Independent
Real-Time
Clock (IRTC)
IEEE ® 1588
Timer
Optional Feature
Program
Flash
(128 to 512 KB)
FlexMemory
(32 to 256 KB)
(2 to 4 KB EE)
Serial
Programming
Interface
(EZPort)
SRAM
(32 to 128 KB)
External
Bus Interface
(FlexBus)
Clocks
Phase-Locked
Loop
Frequency-
Locked Loop
Low/High-
Frequency
Oscillators
Internal
Reference
Clocks
Communication Interfaces HMI
I 2 C
UART
(ISO 7816)
SPI
IEEE 1588
Ethernet MAC
I 2 S
Secure
Digital Host
Controller
(SDHC)
USB OTG
(LS/FS)
USB Charger
Detect (DCD)
USB Voltage
Regulator
GPIO

Diagnostic and Therapy Devices
Key Features
Kinetis K50 MCU features and peripherals in
the integrated measurement engine:
• Ultra-low-power operation
• 2x OPAMP
• 2x TRIAMP
• 2x 12-bit DAC
• 2x 16-bit SAR ADC, up to 31 channels with
programmable gain amplifiers (PGA)
• Programmable Delay Block (PDB)
• I2C • USB connectivity
• ARM Cortex-M4 core with DSP instructions
MCF51MM: Flexis 32-bit
ColdFire V1 MCUs
The MCF51MM256/128 provides ultralow-power
operation, USB connectivity,
graphic display support and unparalleled
measurement accuracy, all in a single 32-bit
MCU, allowing designers to create more
fully featured products at lower cost. The
MCF51MM256/128 is ideal for medical
applications or other applications requiring a
significant amount of precision analog such as
instrumentation and industrial control.
The MCF51MM256/128 is part of the
Freescale Flexis MCU series.
Figure 12-9: MCF51MM256 Block Diagram
Figure 11-11: MCF51MM256 Block Diagram
2x OPAMP
2x TRIAMP
16-bit SAR ADC I2 12-bit DAC LVI
C
PDB
2 x 4-ch. TPM with PWM 2 x SPI
MCG
Features
• ColdFire V1 core delivering a 50 MHz core
speed and 25 MHz bus speed
• Up to 256 KB flash and 32 KB SRAM
• Low-power stop 2 current: 500 nA
(32 KB of active SRAM)
• 2 x general purpose opamps
• 2 x transimpedance amplifiers
• 16-bit SAR high resolution analog-to-digital
converter (ADC)
VREF TOD
PRACMP CMT
2 x KBI 2 x SCI
32-bit V1 ColdFire 50 MHz Core with MAC
Up to 68 GPIO/
16 RGPIO
MiniBus External
USB
Device/Host/
OTG
Bootloader
256 KB 32 KB SRAM
USB ROM
• Analog Comparator with 5-bit digital-toanalog
converter (DAC)
• Internal voltage reference
• USB – device/host/on-the-go controller
• 2 x serial peripheral interface (SPI),
2 x serial communication interface (SCI)
and 1 x I2C • Mini FlexBus (external bus interface EBI)
• Included in Freescale’s Product Longevity
Program
70 Medical Applications User Guide

S08MM: Flexis 8-bit MCUs
The 9S08MM128/64/32 provides ultra-
low-power operation, USB connectivity,
graphic display support and unparalleled
measurement accuracy, all in a single 8-bit
MCU, allowing device designers to create
more fully featured products at a lower cost.
It is ideal for applications requiring a
significant amount of precision analog.
The 9S08MM128/64/32 is part of Freescale’s
Flexis MCU series.
Features
• S08 core delivering a 48 MHz core speed
and 24 MHz bus speed
• Up to 128 KB flash and 12 KB SRAM
• Low-power stop 2 current: 450nA
(12 KB of active SRAM)
• 2 x OPAMP- General purpose opamps
• 2 x TRIAMP- Transimpedance amplifiers
• 16-bit SAR analog-to-digital converter
(ADC) – high resolution ADC
• Analog comparator
• Internal voltage reference
• USB device controller
• 2 x serial peripheral interface (SPI),
2 x serial communications interface (SCI)
and 1 x I2C Figure 12-10: MC9S08MM128 Block Diagram
Figure 11-12: MC9S08MM128 Block Diagram
2x OPAMP
2x TRIAMP
PDB
MCG
VREF TOD
PRACMP CMT
2 x 4-ch. TPM with PWM 2 x SCI
2 x KBI 2 x SPI
8-bit 9S08 48 MHz Core
Diagnostic and Therapy Devices
Up to 68 GPIO
16-bit SAR ADC I2 12-bit DAC LVI
C
USB
Device
Bootloader
128 KB Flash 12 KB SRAM
USB ROM
freescale .com/medical 71

Anesthesia Monitor
13.1
Introduction
An anesthesia monitor is a machine that administers anesthesia to
patients by one of two ways: intravenous or inhaled gas anesthesia.
It exchanges respiratory gases and administers anesthetic gases,
maintaining a balance of gases through the respiratory and
cardiovascular system.
72 Medical Applications User Guide

13.2
Brief Theory
As mentioned in Chapter 12, Ventilation
and Spirometry, the hospital pipeline is the
primary gas source at 50 PSI. This is the
normal working pressure of gas machines.
Oxygen is supplied at approximately 2000
PSI. Anesthesia flow is composed of different
sections. The first is the gas supply and
substance-delivery (Halotane, O2, and N2O)
system. In this part the O2 and the N2O
are mixed in the desired proportion. The
mass flow controller indicates the amount of
anesthetic substance delivered to the patient.
The MCU controls the electromechanical valve
that adjusts the flow rate and the volume of
the gases (Halotane, O2, and N2O).
13.3
Pressure Sensor
This sensor helps the principal MCU take the
pressure of the O2 and N2O. This measurement
and the concentration of the substance are the
variables that control the valves.
To see the configuration of the pressure
sensor and the Freescale portfolio, see
Chapter 12, Ventilation and Spirometry.
13.4
Valve Control
Using a sensor, the MCU takes the
concentration of the substances in the blood.
With these parameters, the MCU knows how
much drug/air/oxygen needs to be delivered
to the patient and the required power to apply
to the valves.
13.5
Principal MCU
The remainder of the process occurs in the
vaporizer (there is a special apparatus to
make this). Here, Halotane, O2 and N2O
are mixed. These substances need to be
vaporized so that the patient can breathe
them and receive the necessary anesthesia.
Therefore the principal MCU has to control
the rate by adjusting the valves, depending
on the pressure of the substances and their
concentrations in the patient.
Figure Anesthesia 12-1: 13-1: Anesthesia Unit Anesthesia MonitorUnit
Unit Monitor Monitor
Mass Flow Controller
Mass Flow Controller
Halotane
Halotane
O 2
O 2
N 2 O
N 2 O
Pressure
Sensor
Pressure
Sensor
Infrared
Infrared Sensor
Sensor
Spectometer
Sensor
Finally, the patient breathes the anesthesia
mixed through the mass flow controller.
The Freescale Kinetis and the PXS20 MCUs
are recommended for this application.
Kinetis K60 MCUs
The Kinetis K60 MCU family includes
512KB-1MB of flash memory, a single
precision floating point unit, IEEE 1588
Ethernet, full- and high-speed USB 2.0
On-The-Go with device charge detect,
Valve Valves
Controls
Display
Display
MCU/MPU
Diagnostic and Therapy Devices
Freescale Technology Optional
MCU Optional Peripherals Analog Sensors
Freescale Technology
Optional
USB
Wireless
Comm
Wireless
Comm
Power
Management
Power
Management
hardware encryption, tamper detection
capabilities and a NAND flash controller.
256-pin devices include a DRAM controller
for system expansion. The Kinetis K60 family
is available in 144 LQFP, 144 MAPBGA, and
256 pin MAPBGA packages.
freescale .com/medical 73
Alarm Alarm
Signal
Conditioning Signal
Conditioning
MCU/MPU
Keypad or
Touch Screen
Keyboard
SPI/I 2 C
SPI/I 2 C
SPI/I 2 C
Anesthesia Unit Monitor
Figure 13-2: Anesthesia Application General Overview
Figure 12-2: Anesthesia Application General Overview
Mass Flow Controller
Valve
Controls
Halotane
O 2
N 2 O
Pressure
Sensor
Infrared
Sensor
Spectometer
Sensor
Infrared
Sensor
Spectometer
Sensor
Display
MCU/MPU
MCU/MPU
Alarm
Signal
Conditioning
Halotane
Keypad or
Touch Screen
SPI/I 2 C
SPI/I 2 C
SPI/I2 Valves Controls
C
MC9S08QG4
O 2
Mass Flow Controller
USB
N 2 O
USB
Wireless
Comm
Power
Management

Diagnostic and Therapy Devices
Key Features
• ARM Cortex-M4 core + DSP. 120-150 MHz,
single cycle MAC, single instruction multiple
data (SIMD) extensions, single precision
floating point unit
• 512 KB-1 MB flash. Fast access, high
reliability with four-level security protection
• Up to four high-speed 16-bit analog-todigital
converter (ADC) with configurable
resolution. Single or differential output mode
operation for improved noise rejection.
500 ns conversion time achievable with
programmable delay block triggering
• System security and tamper detect with
secure real-time clock with independent
battery supply. Secure key storage with
internal/external tamper detect for unsecure
flash, temperature, clock, and supply
voltage variations and physical attack
detection
PXS20 Family of 32-bit Power
Architecture MCUs
The PXS20 targets industrial applications
which require compliance with IEC61508
(SIL 3) safety standard. It reduces design
complexity and component count by putting
key functional safety features on a single chip
with a dual-core, dual-issue architecture,
which can be statically switched between
lockstep mode (redundant processing and
calculations) to decoupled parallel mode
(independent core operation). The PXS20
MCUs are SafeAssure functional safety
solutions.
Key Features
• Dual e200z4 CPU architecture
• Dual processing spheres including: CPU,
DMA, interrupt controller, crossbar and
MPU for logic level fault detection
• Two statically configurable modes of
operation: Lockstep operation (redundant
processing and calculations) and Dual
Parallel Mode (independent core operation)
• Fault Collection Unit, which monitors and
manages fault events
• Error correction coding on RAM and flash
memory allows detection/correction of
memory errors
Figure 12-3: 13-3: Kinetis K60 K60 Family Family Block Block Diagram Diagram
Figure 12-3: Kinetis K60 Family Block Diagram
Core
System Memories
Clocks
Internal and
ARM External
Watchdogs
Debug
Memory
DSP
Interfaces
Protection Unit
(MPU)
Interrupt Floating Point
Controller Unit (FPU)
DMA
Low-Leakage
Wake-Up Unit
Security Analog Timers
and Integrity
Cyclic
Redundancy
Carrier
Check (CRC)
Modulator
Transmitter
Random
Number
Generator
Cryptographic
Periodic
Acceleration
Interrupt
Unit (CAU)
Timers
H/W Tamper
Detection
Unit
Independent
Phase-Locked
Loop
Frequency-
Locked Loop
Low/High-
Frequency
Oscillators
Internal
Reference
Clocks
Communication Interfaces HMI
Xtrinsic
Low-Power
Touch-Sensing
Interface
Real-Time
Clock (RTC)
® Cortex-M4
100/120/150 MHz
16-bit
ADC
FlexTimer
PGA
Analog
Comparator Programmable
Delay Block
6-bit
DAC
12-bit
DAC
Low-Power
Timer
Voltage
Reference
IEEE ® Program Flash SRAM
(256 KB to 1 MB) (64 to 128 KB)
FlexMemory External
(256 to 512 KB) Bus Interface
(4 to 16 KB EE) (FlexBus)
Serial
Cache
Programming
Interface
(EzPort) DDR Controller
NAND Flash
Controller
I GPIO
1588
Timer
2C I
UART
(ISO 7816)
SPI
CAN
IEEE 1588
Ethernet MAC
2 Core
System Memories
Clocks
Internal and
ARM External
Watchdogs
Debug
Memory
DSP
Interfaces
Protection Unit
(MPU)
Interrupt Floating Point
Controller Unit (FPU)
DMA
Low-Leakage
Wake-Up Unit
Security Analog Timers
and Integrity
Cyclic
Redundancy
Carrier
Check (CRC)
Modulator
Transmitter
Random
Number
Generator
Cryptographic
Periodic
Acceleration
Interrupt
Unit (CAU)
Timers
H/W Tamper
Detection
Unit
Independent
Real-Time
Clock (RTC)
Standard Feature
Phase-Locked
Loop
Frequency-
Locked Loop
Low/High-
Frequency
Oscillators
Internal
Reference
Clocks
Communication Interfaces HMI
Xtrinsic
Low-Power
Touch-Sensing
S Interface
Secure
Digital Host
Controller
(SDHC)
USB On-the-Go
(LS/FS)
USB On-the-Go
(HS)
USB Device
Charger Detect
(DCD)
USB Voltage
Regulator
® Cortex-M4
100/120/150 MHz
16-bit
ADC
FlexTimer
PGA
Analog
Comparator Programmable
Delay Block
6-bit
DAC
12-bit
DAC
Low-Power
Timer
Voltage
Reference
IEEE ® 1588
Timer
Program Flash SRAM
(256 KB to 1 MB) (64 to 128 KB)
FlexMemory External
(256 to 512 KB) Bus Interface
(4 to 16 KB EE) (FlexBus)
Serial
Cache
Programming
Interface
(EzPort) DDR Controller
NAND Flash
Controller
I GPIO
2C I
UART
(ISO 7816)
SPI
CAN
IEEE 1588
Ethernet MAC
2 Optional Feature
S
Secure
Digital Host
Controller
(SDHC)
USB On-the-Go
(LS/FS)
USB On-the-Go
(HS)
USB Device
Charger Detect
(DCD)
USB Voltage
Regulator
Figure 12-4: PXS20 Family Block Diagram
Figure 12-4: 13-4: PXS20 PXS20 Family Family Block Block Diagram Diagram
Standard Feature Optional Feature
Core
Core
System
System
Debug
System
System
Core
Core
Frequency
Frequency Modulated PLL
JTAG
JTAG
Nexus
Frequency
Modulated Frequency PLL
e200z4
e200z4
Modulated Software PLL
Watchdog
Software
System
Watchdog Timer
Nexus
System
Boot Assist
Module System (BAM)
Software Modulated PLL
Watchdog
Software
System
Timer Watchdog
e200z4
e200z4
FPU System Interrupt
Controller
Timer
Boot Clock Monitor Assist
Unit
Module (BAM)
Interrupt System
Controller
Timer
FPU
FPU
VLE
VLE
CACHE
MMU
DMA
Interrupt (up to 32-ch.)
Controller
Crossbar
Switch
DMA
(up to 32-ch.) Memory
Protection Unit
Semaphone
Clock Unit Monitor
Unit
VReg
Semaphone
4 x Redundancy Unit
Checker
DMA
(up to 32-ch.) Interrupt
Controller
Crossbar
Switch
DMA
Memory (up to 32-ch.)
Protection Unit
VLE
CACHE
MMU
FPU
VLE
CACHE
Crossbar
Memory Switch
Control
VReg
Crossbar
Switch Communication
CACHE
MMU
3 x
2 x
Memory Timer 4 (6-ch.) x Redundancy Fault Control Memory
Up MMU
Protection to 1 MB
UART
Unit Checker and Protection Unit
Flash
3 x
Collection Unit
3 x
w/ECC
PWM (4-ch.)
SPI
Memory
Up to 4 ADC Control
Communication
2 x
Up to 128 KB
(34-ch.)
Cyclic
CAN
3 x
Redundancy
2 x
SRAM
Timer Cross (6-ch.) Trigger Fault Checker Control External
Up to 1 MBw/ECC
UART
Unit
and
Bus
(32 KB S/B)
Flash
3 Periodic x
Collection Sine Wave Unit
3 x
w/ECC
PWM Interrupt (4-ch.) Timer Generator
SPI
Up to 128 KB
SRAM
w/ECC
(32 KB S/B)
Temperature
Up to Sensor 4 ADC
(34-ch.)
Cross Trigger
Unit
Cyclic
Redundancy
Checker
2 x
CAN
External
Bus
Periodic
Interrupt Timer
Temperature
Sine Wave
Generator
• Designed to address safety requirements
Sensor
outlined in IEC61511 and IEC61508 (SIL3)
• Robust communications CAN/safety port
high speed low latency messaging
• Cross-triggering unit coordinates ADC,
timer and PWM generation and minimizes
CPU interrupt load
• Integrated timer and analog peripherals
support precise control of integrated
electric motor control periphery, enables
the device to control of up to two brushless
3-phase motors or multiple valves with only
minimum interrupt load
74 Medical Applications User Guide

Vital Signs
14.1
Introduction
A vital sign monitor is a multi-parameter device that measures blood
pressure, temperature, oxygen saturation and heart electrical activity to
give a clear view of patient information.
This application constantly monitors the measurements from the ECG,
pulse oximetry, blood pressure and temperature of the patient. For this
application, Freescale offers medical solutions that use our product
expertise in MCUs, sensors, analog and wireless technology for home
portable medical devices, diagnostic and therapy devices and medical
imaging devices. Freescale is dedicated to helping patients live a better
life by driving innovation and enabling medical device manufacturers to
leverage the latest available technology.
freescale .com/medical 75

Diagnostic and Therapy Devices
14.2
Measuring Temperature
The Freescale S08QG family includes
a temperature sensor whose output is
connected to one of the ADC analog channel
inputs. The approximate transfer function of
the temperature sensor can be expressed by
this equation:
Temp = 25 – ((VTEMP – VTEMP25)/m)
For more information about the temperature
sensor, see the document MC9S08QG8/QG4
Device Data Sheet, available at freescale.com.
Features of the ADC module include:
• Linear successive approximation algorithm
with a 10-bit resolution
• Output formatted in 10- or 8-bit rightjustified
format
• Single or continuous conversion (automatic
return to idle after a single conversion)
• Configurable sample time, conversion
speed and power
• Conversion complete flag and interrupt
• Input clock selectable from up to four
sources
• Operation in Wait or Stop3 modes for low
noise operation
For more information about how to send
the ADC values to the main MCU, see the
application note titled Analog-to-Digital
Converter on an I2C Bus Using
MC9S08QG8 (document AN3048),
available at freescale.com.
14.3
ECG Monitoring
For more information about designing
ECG, pulse oximetry and blood pressure
applications, see the relevant chapters.
Figure 14-1: Vital Signs Monitoring General Block Diagram
Vital Signs Monitor
Temp
Sensor
12 Leads
Finger
Clamp
Amp
Freescale Technology
Electrical
Protection and Mux
Switching Module
Red and
Infrared LEDs
Receptor Diode
Arm Valve Pressure Sensor
Pump Motor
Motor Control
Optional
Signal
Conditioning
Signal
Conditioning
SensorAmp
14.4
Pulse Oximetry Monitoring
A pulse oximeter is a device that measures
the amount of oxygen saturation in the blood.
This parameter is useful for patients with
metabolic disorders like respiratory acidosis,
alcalosis, chronic obstructive pulmonary
disease (COPD) and restrictive pulmonary
disease.
Keypad or
Touch Screen
MCU/MPU
14.5
Blood Pressure
Monitoring
Power
Management
A blood pressure monitor is a device that
measures the systolic and diastolic blood
pressure by inflating a cuff until it equals
the systolic pressure and then deflates until
the diastolic pressure is bypassed. Other
parameters can be measured like mean
arterial pressure and heart rate.
76 Medical Applications User Guide
ADC
Figure 14-2: General Overview of Temperature Measurement
Figure 13-2: General Overview of Temperature Measurement
AD26
ADC Channel
PWM
Figure 14-3: ECG Monitoring General Overview
Figure 13-3: ECG Monitoring General Overview
AD26
ADC Channel
I 2 C
I 2 C
Principal
MCU/MPU
Principal
MCU/MPU
USB
Wireless
Comm

14.6
Motor Control with
Freescale Devices
The Freescale MPC17C724 is a 0.4 amp dual
H-bridge motor driver IC with the following
features:
• Built in 2-channel H-bridge driver
• Provides four driving modes
• Forward
• Reverse
• Break
• High impedance
• Direct interface to the MCU
• Low ON-resistance, RDS(ON) = 1.0 Ω
(typical)
• PWM control frequency 200 kHz (max)
To design keypad, power management,
wireless communications and USB modules,
see Chapter 3 Telehealth Systems Introduction.
For a display with a touch screen, see Chapter
10.2, Electrocardiograph and Portable ECG.
For wireless communication, power
management, keypad and speaker
implementation modules, see Chapter 3,
Telehealth Systems Introduction.
Table 13-1. S08QG MCU Family
Features S08QG
Core HCS08
Flash (byte) 8K/4K
RAM (byte) 512/256
Bus frequency 10 MHz
ADC Up to 8 channels (10 bits)
Analog comparator Yes
Keyboard interrupt Up to 8 pins
Timers (up to) 1- to 16-bit timer (2
channels), one 16-bit timer
SCI 1
SPI 1
I2C 1
Operational voltage 1.8V to 3.6V
Figure 13-4: 14-4: Signal Conditioning to ECG to ECG Monitoring Monitoring
Right Hand
Right Leg Left Leg
Diagnostic and Therapy Devices
To MCU
ADC input
freescale .com/medical 77
Left Hand
Analog
Frond End
Electrodes
Multiplexer
and Isolator
Instrumentation
Amplifier
Figure 14-5: General Overview of Pulse Oximetry Monitoring
Figure 13-5: General Overview of Pulse Oximetry Monitoring
Finger
Clamp
Switching Module
Red and
Infrared LEDs
Receptor Diode
Signal
Conditioning
Band Pass
Filter
To Principal
MCU/MPU
Figure 14-6: Signal Conditioning for Pulse Oximetry Monitoring
Figure 13-6: Signal Conditioning for Pulse Oximetry Monitoring
Figure 14-7: General Overview of Pressure Monitoring
Figure 13-7: General Overview of Pressure Monitoring
Arm
Valve
Pump
Motor
Pressure
Sensor
Motor
Control
PWM
Sensor
Amp
To Principal
MCU/MPU

Hospital Admission Machine
15.1
Introduction
With the increasing prevalance of technology in the medical market,
administrators are open to infusing that technology into hospitals to
help increase the quality of service.
Automated hospital admission machines, tracking devices/bracelets
and automatic inventory control are just some of the applications the
medical team is working on at Freescale. By leveraging our strengths
in Vybrid Controller Solutions, Kinetis MCUs, ColdFire MCUs, and
i.MX processors, wireless communications and PowerQUICC network
processing, Freescale strives to bring connected intelligence to hospitals.
15.2
Hospital Admission
Machine
A hospital admission machine helps patients
and doctors increase the efficiency of a
hospital through automating procedures
which usually take time from the nurses and
administrative employees.
These solutions need to integrate a broad
range of medical devices in order to perform
necessary functions for the physician and
increase the range of early diagnosis/
symptoms and signs that can alert medical
staff to acute complications in patients being
monitored at home (using portable mode) or in
specific strategic places such as malls (using
medical kiosks).
78 Medical Applications User Guide

State-of-the-art technology—including
integrated MCUs such as Freescale’s Kinetis
8-bit 9SS08MM, and 32-bit MCF51MM—
allow the designer to achieve portability
for touch sensing and medical-grade
communication (following Continua Health
Alliance guidelines) with libraries that are
downloadable from freescale.com/medical.
These elements enable solutions focused on
preventive medicine, which ultimately reduce
patients’ acute complications and costs
related to their treatment. This can help health
institutions redirect money used for treatment
toward prevention and can help insurance
companies cut costs.
The hospital kiosk includes a touch-sensing
interface that allows the user to navigate the
machine’s interface. This flat surface makes
the machine easier to disinfect after each user.
It is more difficult to disinfect a machine with
mechanical buttons that can hold pathogens
such as bacteria and viruses in the edge of
the buttons.
The kiosk includes a magnetic card reader
used to identify the patient and to keep a
record of the patient’s abbreviated e-chart.
The e-chart contains the following data:
• ID fields: First name, last name, birth date,
gender, contact information
• Family medical history: Cancer,
cardiovascular disease, chronic
degenerative diseases such as arthritis,
kidney disease, asthma, neurological
disorders, etc.
• Personal medical history: Medicines,
surgeries, diseases, etc.
• Non-pathological personal history: Blood
type, alcohol and tobacco use, drug abuse,
allergies, etc.
Once the patient is identified through the
magnetic card, the machine can take the
following measurements:
• Capillary blood glucose levels
• Systolic, diastolic and mean arterial
pressure
• Weight, height and body mass index
• Temperature
• Heart rate
• EKG DI
• Oxygen saturation level (SaO2)
• Maximum expiratory and inspiratory
flow peak
• Inspiratory and expiratory lung volume
After this information is entered, a test result
paper is printed and a remote database is
updated with these readings. If the kiosk
detects a critical problem, it sends the report
to a mobile device that could report the
finding to a physician or health care provider.
A step-by-step video shows how to perform
these tests so that the user can perform
the tests without help from a health care
professional. With language support in
English, Spanish and Japanese, the user
sees and hears how to perform these tests.
As users become more familiar with the
device, they may pay less attention to the
instructions. This is why we also offer the
patient monitor interface.
Diagnostic and Therapy Devices
Figure 15-1: Hospital Admission Machine General Block Diagram
Hospital Admission Machine
Height
Ultrasonic
Sensor
Electronic Wireless
Patient’s Chart
Pulse Oximetry/
Heart Rate/
Glucometer
Digital Weight
Freescale Technology Optional
Blood Pressure
Monitoring
For an easy-to-use mode, the main core of
the kiosk can be separated. This creates a
USB-powered portable device for home use
or use at remote facilities when a physician is
not nearby.
The following sections describe the parts of
the system (some of them have already been
described in previous chapters):
• Weight scale
• Height ultrasonic sensor
• Thermometer
• Blood pressure monitor (systolic, diastolic,
mean arterial pressure)
• Heart rate monitor
• One-lead EKG (DI)
• Pulse oximeter
• Blood glucose meter
• Spirometer (air flow and lung volume)
freescale .com/medical 79
ITO Glass
Electrodes
USB
LEDs
RS-232
Xcvr
Secondary
MCU
Ethernet
PHY(100 Mbps)
USB
Power
Switch
Buzzer
4 x 5
Keypad
Matrix
BDM
Keypad
or
Touch
Screen
Figure 15-2: Analog Configuration for LEDs and Buzzer
Figure 14-2: Analog Configuration for LEDs and Buzzer
330Ω
A K
o.1 uF
120Ω
1kΩ
Display
MCU/MPU
32 MB
DDR
SDRAM
Backlight
Inverter
Level
Shift
Xcvr
Wireless
Comm
Power
Management
Non-
Volatile
Memory

Diagnostic and Therapy Devices
15.3
Patient Height and Weight
The patient’s height is taken by an ultrasonic
sensor which measures the distance between
the head and the sensor. An MCU takes the
data produced by the transducer and uses an
equation to calculate the distance between
the sensor and the head, then calculates the
difference between this distance and the total
distance to the floor.
The patient’s weight is taken by a pressure
sensor. This operation is explained in the
“Ventilation and Respiration” application
article. In general, after signal conditioning
produces a voltage, this voltage is passed
through the ADC of a MCU to be processed
and then passed by RS-232 or USB to the
principal MPU. The general block diagram
shows that the weight of the patient is passed
through RS-232, although you can transmit
by USB (optional). If RS-232 is used, it is
necessary to add a MAX232 device according
to the protocol (see Figure 15-4).
15.4
Patient Interface
The patient has an interface to communicate
with the admission machine. This interface is
composed of a touch screen display, LEDs
and a buzzer to warn if a decision must be
made or if a process is finished. This module
is developed with a secondary MCU, such as
the Freescale S08QE.
Figure 14-3: Portable Monitoring System
Figure 15-3: Portable Monitoring System
Figure 14-4: 15-4: Measuring Patient Height Height
Anesthesia Unit Monitor
Mass Flow Controller
Halotane
Height
Ultrasonic
Sensor
Transmitter Receptor
D=1/2Vt
O
Pressure
2
Sensor
Figure 15-5: Configuration to Measure Patient Weight
Figure 14-5: Configuration to Measure Patient Weight
N O 2
Infrared
SPI/I
Sensor
MCU/MPU
Freescale Pressure Sensors
MPXx5004
MPXx5004
Optional Instrument
Amplifier
MPXC2011DT1
MPXx12
MPXx5010
MPXx2010
Spectometer
Sensor
MPXV 2053GVO
MPXV5100
ADC
Display
Keypad or
Touch Screen
2 SPI/I
C
2C Freescale Technology
Optional
Valve
Controls
Wireless
Comm
SCI
Power
Management
MAX232
80 Medical Applications User Guide
Alarm
Signal
Conditioning
USB

15.5
Communication Interfaces
USB Power Switch
When the patient arrives at the hospital,
special devices take the principal vital signs of
height, weight and heart rate. These devices
are connected to the principal system. When
the devices are connected by USB, the
devices are powered on and the principal
MPU starts the communication as host.
The USB port is implemented in a regulator
(MC33730) that provides 5V at 2A out.
However, the devices only support 500 mA.
Therefore, it is necessary to add a 500 mA
fuse to regulate the current. The USB module
of the principal MPU is configured as a host
that can turn on the external devices and start
communication between the external devices
and the principal MPU.
The MPUs recommended for this application
integrate two or more hosts, allowing more
than one USB device without using a hub.
For a list of recommended MPUs, visit
freescale.com/medical.
Serial Communication Interface
Serial communications interface (SCI) is an
asynchronous serial communications bus
that an MCU uses to communicate with other
MCUs or external devices using SCI. Two
signal lines are used with SCI: TXD (transmit)
and RXD (receive). The two-wire SCI bus
operates in full-duplex mode (transmitting and
receiving at the same time). SCI uses either an
8- or 9-bit data format, with data sent using
non-return-to-zero (NRZ). The SCI bus may
also be set up as a single wire interface, using
the TXD pin to both send and receive data.
The SCI is a generic controller which allows
the integration of RS232, RS422 and RS485
serial transceivers.
Figure 15-6: USB Port Connections
Figure 14-6: USB Port Connections
Power
Source
Figure 15-7: USB General Configuration
Figure 14-7: USB General Configuration
Figure 15-8: SCI Tram
Figure 14-8: SCI Tram
Diagnostic and Therapy Devices
MC33730
0 1 0 0 1 1 0 1 1 1
freescale .com/medical 81

Diagnostic and Therapy Devices
Data can be sent as 8- or 9-bit words, least
significant bit (LSB). A START bit marks
the beginning of the frame, and is active
low. Figure 14-8 shows a framed 8-bit data
word. The data word follows the start bit.
A parity bit may follow the data word after
the most significant bit (MSB) depending on
the protocol used. A mark parity bit (always
set high), a space parity bit (always set low)
or an even/odd parity bit may be used. The
even parity bit will be a one if the number of
ones/zeros is even or a zero if there is an odd
number. The odd parity bit will be high if there
are an odd number of ones/zeros in the data
field. A stop bit will normally follow the data
field. The stop bit is used to bring the signal
rests at logic high following the end of the
frame, so when the next start bit arrives it will
bring the bus from high to low. Idle characters
are sent as all ones with no start or stop bits.
Freescale MCUs provide 13-bit baud. The SCI
modules can operate in low-power modes.
Ethernet PHY (100 Mbps)
To connect the MCU to the Internet or
to control the system remotely, you can
implement an Ethernet communication
interface. This needs coupling impedance for
the RJ-45 connection.
15.6
Backlight Inverter
A backlight is a form of illumination used
in liquid crystal displays (LCDs). Backlights
illuminate the LCD from the side or back of
the display panel, unlike front lights, which are
placed in front of the LCD.
Figure 14-9: 15-9: Serial Serial Communication Interface Interface General General Configuration Configuration
+
+
+
1
2
3
4
5
6
7
8
ADC
SCI
+
MAX 232
82 Medical Applications User Guide
Rx
Tx
16
15
14
13
12
11
10
9
Figure 14-10: 15-10: Ethernet Interface Circuitry
+
+
+
+
1
2
3
4
5
6
7
8
MPU/
SCI
+
MAX 232
Rx
Tx
16
15
14
13
12
11
10
9
+

15.7
Multimedia Applications
with i.MX53 Family
The i.MX53 family of processors represents
our next-generation of advanced multimedia
and power-efficient implementation of the
ARM ® Cortex-A8 core with core processing
speeds up to 1.2 GHz. It is optimized for
both performance and power to meet the
demands of high-end, advanced applications.
Ideal for a broad range of applications in the
consumer, automotive, medical and industrial
markets, the i.MX53 includes an integrated
display controller, full HD capability, enhanced
graphics and connectivity features. The
i.MX53 family also boasts a companion power
management IC (PMIC)—MC34708—designed
exclusively for i.MX processors.
CPU Complex
• Up to 1.2 GHz ARM Cortex-A8 CPU
• 32 KB instruction and data caches
• Unified 256 KB L2 cache
• NEON SIMD media accelerator
• Vector floating point coprocessor
Multimedia
• Multi-format HD1080p video decoder and
720p video encoder hardware engine
• 24-bit primary display support up to
WsXGA resolution
• OpenGL ES 2.0 and OpenVG 1.1 hardware
graphics accelerators
• 18-bit secondary display support
• Analog HD720p component TV output
• High quality hardware video de-interlacing
• Image and video resize, inversion and
rotation hardware
• Alpha blending and color space conversion
• Display quality enhancement: Color
correction, gamut mapping, gamma
correction
Figure 15-11: i.MX53 Family Block Diagram
i.MX536 Block Diagram
Smart DMA
External Memory Interface
• LP-DDR2, LV-DDR2 and DDR3 SDRAM,
16/32-bit
• SLC/MLC NAND flash, NOR, 8/16-bit
Graphic LCD Applications with
ColdFire
For other applications in which graphic LCD
display is fundamental, the ColdFire products
offer a wide range of on-chip drivers for
different screen resolution.
Diagnostic and Therapy Devices
Clock Reset
Temp
Monitor
ARM ® System Control Core/Internal Memory Standard Connectivity
Cortex-A8
Fast IrDA
UART x 5
GPT
PWM x 2
System
Buses
Timers
Watchdog
x 2
EPIT x 2
Power Mgmt. and Analog
LDO Supply
32 kHz Osc
x 2
PLL x 4
Security
eFuses RTIC
Sahara v4
TrustZone
SCC v2
SRTC
Secure JTAG
ESAI
SSI/I2 System Debug Audio Display I/F
S x 3
SPDIF Tx/Rx
ASRC
Analog VGA Out
LVDS
Parallel (from IPU)
freescale .com/medical 83
Cache
Neon
ETM
VFP
ROM RAM
Multimedia
GPU
OpenGL ES 2.0 OpenVG 1.1
Video Encode/
Decode
Resizing and
Blending
Inversion and
Rotation
De-Interlacing/
Combining
VPU
IPU
TV Out
Image
Enhancement
Camera
Interface
CSPI
I 2 C x 3
HS USB OTG + PHY
HS Host + PHY
Keypad
GPIO
Advanced Connectivity
Ethernet + IEEE ® 1588
CAN x2/MLB 50
HS ULPI Host x 2 Camera Interface
External Memory I/F
2 GB DDR2/DDR3/LV-DDR2/LP-DDR2
External Storage I/F
SLC/MLC NAND
NOR
PATA
SATA
eMMC/SD

Digital Stethoscope
16.1
Introduction
A digital stethoscope is a device that uses ultrasound waves to detect
different types of tissue and movements within the body, such as
produced by heart contractions and relaxation or even blood flow
through the arteries, using an ultrasonic probe.
The functioning is based on the Doppler Effect, which consists of the
wavelength variation of any wave sent or received by a moving object.
In this case, the source sends acoustic waves to the heart. Part of
the energy bounces back. However, because the heart is beating, the
bounced waves are affected by the Doppler Effect. This changes their
frequency. Therefore with simple algorithms the heartbeats
are detected.
84 Medical Applications User Guide

16.2
Ultrasonic Probe
The ultrasonic probe may consist of an
oscillator (X1 in Figure 16-2) that generates an
ultrasound frequency (for these applications,
the range is 1–3 MHz) followed by an amplifier
(U2 in Figure 16-2) to condition the sine
waveform in volts.
This waveform is applied to the transmitter
transducer to send vibrations through the
body and bounce back when the density of
the medium changes. Another transducer is
used to receive the bounced vibrations and
convert them to electrical signals. This signal
is amplified using an instrumental amplifier
and is sent to a band-pass filter. The filtered
signal is sent to a phase-locked loop to
generate a voltage signal, which depends on
the frequency applied.
For implementations of the instrumentation
amplifier and band-pass filter, see the
Appendix of this document.
16.3
Electrical Protection
Any time an AC-powered medical device
comes into contact with a patient, the system
must be designed with electrical protection in
mind. Electrical protection limits the current to
a non-harmful range of 6–10 mA maximum,
avoiding the probability of electrical discharge.
This also should provide isolation between the
power source of the device and the sensor
that is in contact with the person.
In the transmitter ultrasound probe example
(Figure 16-2) the resistor R3 limits the current
to transformer T1. Transformer T2 provides
isolation between the circuit and the patient’s
body. Transformers T1 and T2 must have a
1:1 relationship, and should not be affected by
the operational frequency of the transducers.
Figure 16-1: Digital Stethoscope General Block Diagram
Digital Stethoscope
Ultrasound Transducer
Freescale Technology
Core
• ARM ® Core
• ARM Cortex-M4
Core 72/100 MHz
• DSP
® Cortex-M4
Core 72/100 MHz
• DSP
Signal Conditioning
• ADC
• DAC
• OPAMP
• TRIAMP
Audio Power
Amplifier
Potentiometer
Volume
Diagnostic and Therapy Devices
freescale .com/medical 85
MCU
HMI
• External
Bus Interface
(FlexBus)
Figure 15-3: 16-2: Transmitter Ultrasonic Ultrasonic Probe Probe Example Example
U1
X1
C1 C2
Figure 16-3: Receiver Ultrasonic Probe Example
Figure 15-4: Receiver Ultrasonic Probe Example
Transducer
T2
R1
Instrumentation
Amplifier
R2
U2
Band-Pass
Filter
LCD
Active
Speaker
R3 T1 Transducer
Phase-Locked Loop
fin
feedback
Vout
To MCU
ADC input

Diagnostic and Therapy Devices
16.4
Signal Conditioning
Signal conditioning can be implemented using
a band-pass filter to reject noise. Using an
active filter, the signal can be conditioned
to determine values. For details about filter
design, refer to the Appendix.
The signal at the output of the band-pass filter
is sent to a phase-locked loop to generate
a frequency-dependent voltage. The phaselocked
loop must be configured so that the
frequency of the look-in range matches the
band-pass filter bandwidth. This signal is
applied to an input of the analog-to-digital
converter embedded on the MCU.
16.5
LCD Display
The MCU is responsible for processing
the information acquired according to an
algorithm and displaying the data on an
LCD screen. Freescale provides 8-bit MCUs
with embedded LCD controllers such as the
MC9S08LL, MC9RS08LE, MC9RS08LA and
MC9S08LC families. Ultra-low-power MCUs
with LCD drivers are in the LL family. On the
high end, consider Kinetis or Vybrid MCUs.
For more information about LCD devices
and connections, see Chapter 6, Blood
Glucose Meter.
For information about a digital stethoscope
reference design, download DRM132 Medical
Stethoscope Design Reference Manual.
K50 Measurement MCUs
The K50 MCU family is pin, peripheral and
software compatible with other Kinetis MCUs
and provides designers with an analog
measurement engine consisting of integrated
operational and transimpedance amplifiers
and high-resolution ADC and DAC modules.
The family also features IEEE 1588 Ethernet
and hardware encryption, full-speed USB
2.0 On-The-Go with device charger detect
capability and a flexible low-power segment
LCD controller with support for up to 320
Figure 16-4: Ultrasonic Probe Elements Block Diagram
Figure 15-5: Ultrasonic Probe Elements Block Diagram
Oscillator
Phase-Locked
Loop
to MCU
ADC input
Amplifier
Band-Pass
Filter
Instrumentation
Amplifier
Probe Electrical Protection Amplifier Signal Conditioning
86 Medical Applications User Guide
Current
Limiter
Figure Figure 15-2: 16-5: Doppler Doppler Effect Effect Example Example
Waves emitted
by a static object
Electrical
Isolation
Waves emitted
by a moving object
Transmitter
Transducer
Receiver
Transducer
Signal sent
Signal
bounced

segments. Devices start from 128 KB of flash
in 64-pin QFN packages extending up to 512
KB in a 144-pin MAPBGA package.
Key Features
The Kinetis K50 MCU has the next features
and peripherals in its integrated measurement
engine:
• Ultra-low-power operation
• 2x OPAMP
• 2x TRIAMP
• 2x 12-bit DAC
• 2x 16-bit SAR ADC, up to 31 channels with
programmable gain amplifiers (PGA)
• Programmable Delay Block (PDB)
• I2C • USB connectivity
• ARM Cortex-M4 core with DSP (Digital
Signal Processor) instructions
MCF51MM: Flexis 32-bit
ColdFire V1 MCUs
The MCF51MM256/128 provides ultralow-power
operation, USB connectivity,
graphic display support and unparalleled
measurement accuracy, all in a single 32-bit
MCU, allowing designers to create more
fully featured products at lower cost. The
MCF51MM256/128 is ideal for medical
applications or other applications requiring a
significant amount of precision analog such as
instrumentation and industrial control.
The MCF51MM256/128 is part of the
Freescale Flexis MCU series.
Features:
• ColdFire V1 core delivering a 50 MHz core
speed and 25 MHz bus speed
• Up to 256 KB flash and 32 KB SRAM
• Low-power stop 2 current: 500 nA
(32 KB of active SRAM)
• 2 x general purpose opamps
• 2 x transimpedance amplifiers
• 16-bit SAR high resolution analog-to-digital
converter (ADC)
• Analog Comparator with 5-bit digital-toanalog
converter (DAC)
• Internal voltage reference
• USB – device/host/on-the-go controller
Figure 16-6: Kinetis K50 Family Block Diagram
Figure 15-6: Kinetis K50 Family
Security
and Integrity
Cyclic
Redundancy
Check (CRC)
Random
Number
Generator
Cryptographic
Acceleration
Unit (CAU)
Core
ARM ® Cortex-M4
72/100 MHz
Debug
Interfaces
Interrupt
Controller
Standard Feature
Diagnostic and Therapy Devices
System Memories
Internal and
External
Watchdogs
Memory
Protection Unit
(MPU)
Xtrinsic
Low-Power
Touch-Sensing
Interface
Segment
LCD Controller
freescale .com/medical 87
DSP
Analog
16-bit
ADC
PGA
Analog
Comparator
6-bit
DAC
12-bit
DAC
Voltage
Reference
OPAMP
TRIAMP
DMA
Low-Leakage
Wake-Up Unit
Timers
FlexTimer
Carrier
Modulator
Transmitter
Programmable
Delay Block
Periodic
Interrupt
Timer
Low-Power
Timer
Independent
Real-Time
Clock (IRTC)
IEEE ® 1588
Timer
Optional Feature
Figure 16-7: MCF51MM256 Block Diagram
Figure 15-7: MCF51MM256 Block Diagram
2x OPAMP
2x TRIAMP
PDB
MCG
Program
Flash
(128 to 512 KB)
FlexMemory
(32 to 256 KB)
(2 to 4 KB EE)
Serial
Programming
Interface
(EZPort)
SRAM
(32 to 128 KB)
External
Bus Interface
(FlexBus)
Clocks
Phase-Locked
Loop
Frequency-
Locked Loop
Low/High-
Frequency
Oscillators
Internal
Reference
Clocks
Communication Interfaces HMI
I 2 C
UART
(ISO 7816)
SPI
IEEE 1588
Ethernet MAC
VREF TOD
PRACMP CMT
2 x 4-ch. TPM with PWM 2 x SPI
2 x KBI 2 x SCI
I 2 S
Secure
Digital Host
Controller
(SDHC)
USB OTG
(LS/FS)
USB Charger
Detect (DCD)
USB Voltage
Regulator
16-bit SAR ADC I2 12-bit DAC LVI
C
32-bit V1 ColdFire 50 MHz Core with MAC
GPIO
Up to 68 GPIO/
16 RGPIO
MiniBus External
USB
Device/Host/
OTG
Bootloader
256 KB 32 KB SRAM
USB ROM

Diagnostic and Therapy Devices
• 2 x serial peripheral interface (SPI),
2 x serial communication interface (SCI)
and 1 x I2C • Mini FlexBus (external bus interface EBI)
• Included in Freescale Product Longevity
Program.
S08MM: Flexis 8-bit MCUs
The 9S08MM128/64/32 provides ultralow-power
operation, USB connectivity,
graphic display support and unparalleled
measurement accuracy, all in a single 8-bit
MCU, allowing device designers to create
more fully featured products at a lower cost.
It is ideal for applications requiring a
significant amount of precision analog.
The 9S08MM128/64/32 is part of Freescale’s
Flexis MCU series.
Features:
• S08 core delivering a 48 MHz core speed
and 24 MHz bus speed
• Up to 128 KB flash and 12 KB SRAM
• Low-power stop 2 current: 450nA
(12 KB of active SRAM)
• 2 x OPAMP- General purpose opamps
• 2 x TRIAMP- Transimpedance amplifiers
• 16-bit SAR analog-to-digital converter
(ADC) – high resolution ADC
• Analog comparator
• Internal voltage reference
• USB device controller
• 2 x serial peripheral interface (SPI),
2 x serial communications interface (SCI)
and 1 x I2C 16.6
Fetal Heart Rate Monitor
A fetal heart rate monitor is a target
application of digital stethoscopes. It provides
an audible simulation of the heart beats of a
fetus inside the mother’s womb and displays
the number of beats per minute. Fetal heart
rate monitors are increasingly being used in
the home, allowing parents to listen to their
baby’s heart beat.
Figure 16-9 shows the basic block diagram of
a fetal heart rate monitor.
Figure 16-8: MC9S08MM128 Block Diagram
Figure 15-8: MC9S08MM128 Block Diagram
2x OPAMP
2x TRIAMP
PDB
MCG
Figure 16-9: Fetal Heart Rate Monitor General Block Diagram
Fetal Heart Rate Monitor General
Signal
Conditioning
Electrical
Protection
Ultrasonic Probe
Power
Management
Amplifier
Freescale Technology Optional
VREF TOD
16-bit SAR ADC I2 12-bit DAC LVI
C
PRACMP CMT
2 x 4-ch. TPM with PWM 2 x SCI
2 x KBI 2 x SPI
8-bit 9S08 48 MHz Core
Pressure Sensor Wireless Comm
88 Medical Applications User Guide
ADC
Keypad
MCU
PWM
Up to 68 GPIO
USB
Device
Bootloader
128 KB Flash 12 KB SRAM
USB ROM
Segment LCD

Powered Patient Bed
17.1
Introduction
A simple hospital bed has evolved into a highly networked appliance
that integrates sophisticated processors to monitor patient status
and control the bed’s power-assisted functions. The result is a more
comfortable bed and one that is easier for health care professionals
to move and adjust.
freescale .com/medical 89

Diagnostic and Therapy Devices
17.2
Using Motors for Patient
Positioning
Pressure ulcers or decubitus ulcers (bedsores)
are one of the most common complications of
patients who cannot change position in a bed.
Bedsores can be caused by sweat, humidity
and temperature but are mainly the result
of unrelieved pressure applied by the bones
to the skin and tissue. This is why the most
common places for bedsores are the sacrum,
elbows, knees and ankles.
To avoid bedsores, hospitals and health
care providers use irregular bed surfaces to
distribute pressure along the whole body while
electric motors allow the patient easily switch
positions with just the push of a few buttons.
Electric motors are clean and relatively
efficient. This makes them a much better fit
for use in hospital beds rather than pneumatic
or hydraulic alternatives. An electronic motor
system can be used to adjust the height of
the bed and provide movement to the bed’s
wheels. A typical system containing an MCU,
an H-bridge and a motor is shown in
Figure 17-2.
The requirements for an MCU vary based
on the size of the motor and the required
efficiency. Most patient bed applications
require between 32 to 100 MHz, 16 to 156 KB
of flash memory, 2 to 64 KB of SRAM, a highly
accurate timer and the ability to synchronize
the timer with the analog to digital converter
(ADC). The requirements for an H-bridge
also vary, but most beds require a monolithic
power IC comprising control logic, charge
pump, gate drive and low RDS(ON) MOSFET
output H-bridge circuitry in a small surface
mount package.
Freescale offers a wide variety of products
specifically for motor control systems ranging
from digital signal controllers (DSC) to MCUs
and H-bridges. An ideal MCU and H-bridge
solution for a bed is an MCF51AC256 paired
with the flexible, low-power MC33926. In
Figure 17-1: Powered Patient Bed General Block Diagram
Powered Patient Bed
Infusion
Pump
Motor
Driver
Patient
Monitor
Power
Management
Infusion
Pump
Control
Patient
Monitor
Control
Other
Devices
Freescale Technology
Optional
some cases, depending on the complexity
of the motor system, a single DSC may be
sufficient to control the motor. Freescale’s
MC56F800x family is an alternative costoptimized
solution for real-time motor control.
17.3
Integrated Real-Time
Patient Monitoring
A powered patient bed must be equipped to
monitor the status of the patient and transmit
the data remotely to a nurse station. Typical
patient monitoring functions consist of blood
pressure monitoring, heart rate monitoring,
a pulse oximetry unit, ECG, blood glucose
meters and an infusion pump.
The modules shown in Figure 17-1 provide
extra features allowing health care providers
and the patient’s relatives to offer comfort to
the patient. Some of these modules include a
tilt accelerometer and motor driver to control
the bed’s tilt, powered wheels to facilitate
movement of the patient to different areas
of the hospital, USB and Ethernet ports to
provide connection with a PC or the hospital
network, VoIP gateway to provide direct
communication to the nurses’ station, and an
LCD screen and keypad for user interface.
17.4
Integrated Tilt Control
The tilt control module is used mainly for the
safety and comfort of the patient. Although
hospital beds are often maneuvered in many
directions and in some cases, in an urgent
manner, the safety of the patient must be
paramount at all times. Electronic sensors
can be used to monitor the tilt of the bed and
provide an alarm if the bed is at an unsafe
angle. Furthermore, the tilt control module is
used to position the patient in the bed at the
most ideal angle for the patient’s comfort.
This is the most prevalent use of the tilt
control module.
Accelerometers can be used to measure
both dynamic and static acceleration. Tilt is
a static measurement where gravity is the
acceleration being measured. Therefore, to
achieve the highest degree of resolution of
a tilt measurement, a low-g, high-sensitivity
90 Medical Applications User Guide
UART
UART
UART
LCD
Controller
LCD
Display
MCU/MPU
SPI
USB
MII
Keypad or
Touch
Screen
Wireless Comm
IEEE ® 802.11x Wi-Fi ®
10/100 Ethernet PHY
CAN
XSCVR
Accelerometer
CAN Bus
CAN
XSCVR
Bed Tilt
Control
Motor
Driver
Bed Tilt
Motors
Nursing
Station
Wired
Network
CAN
XSCVR
Wheel Motor
Control
Motor
Driver
Wheel
Motors
VoIP
Gateway to
Public Phone
Network
Pressure
Sensor
CAN
XSCVR
Pump
Control
Motor
Driver
Pump
Motors

accelerometer is required. The Freescale
MMA845xQ series accelerometers are ideal
solutions for XY and XYZ tilt sensing.
A simple tilt application can be implemented
using an MCU that has one or two ADC
channels to read the analog output voltage of
the accelerometers. For a safety application,
an I/O channel can be used to send a signal
to the MCU to turn power a particular medical
device at a determined angle.
Selecting the right accelerometer depends on
the angle of reference and how the device is
mounted. This allows the designer to achieve
a high degree of resolution for a given solution
due to the nonlinearity of the technology.
To obtain the most resolution per degree
of change, the sensor must be mounted
with the sensitive axis parallel to the plane
of movement where the most sensitivity is
desired. For example, if the degree range
that an application is measuring is 0° to 45°,
then the printed circuit board (PCB) would be
mounted perpendicular to gravity. An X-axis
device would be the best solution.
17.5
Integrated Intercom
Using VoIP
VoIP intercom applications can improve
communication throughout a facility across
either wired or wireless networks. Maintaining
support resources for only one network can
lead to substantial cost savings, however, the
greatest opportunity lies in the ability to deploy
and integrate new productivity applications
and enhanced voice services. A VoIP gateway,
for instance, can help seamlessly integrate a
patient’s monitored data into the underlying
hospital network.
Figure 17-2: Electronic Motor System
V DD
MCU
A VoIP intercom application should deliver
an attractive and intuitive user interface and
maintain good audio quality from end to
end with options for video connectivity. No
additional switching equipment is required to
implement these systems across an existing
network. To meet these needs, the system
MPU must feature a high level of integration
to simplify a design for seamless video,
voice and network connectivity. It must have
enough processing performance and network
bandwidth to simultaneously transfer data
from many sources, including a keypad, touch
screen display panel and voice inputs and
outputs.
Freescale offers a comprehensive hardware
and software solution for commercial
VoIP applications that meet these specific
requirements. The i.MX product family contains
processors up to 800 MHz with the proper mix
of memory and peripherals for creating the
VoIP solution.
freescale .com/medical 91
SF
FB
IN1
IN2
INV
SLEW
D1
D2
EN
Diagnostic and Therapy Devices
33926
VPWR
CCP
OUT1
OUT2
PGND
AGND
Motor
V PWR

Diagnostic and Therapy Devices
Table 17-1. Freescale Technologies for Diagnostic and Therapy
Device Description Key Features Application Notes and
Alternate Options
Electrocardiograph (ECG)
i.MX28x ARM9 Applications Processor 454 MHz ARM9 core, power management, LCD controller, touch screen,
DDR2/mDDR/NAND, Ethernet, USB PHY x2,

Table 17-1. Freescale Technologies for Diagnostic and Therapy continued
Diagnostic and Therapy Devices
Device Description Key Features Application Notes and
Alternate Options
Vital Signs
S08MM Flexis 8-bit MCU Ultra-low-power MCU, analog measurement engine, USB Flexis S08JE
MCF5227X ColdFire V2 MCU with Touch Screen,
LCD Controller and USB
32-bit low-cost MPU, LCD, USB OTG, CAN MCF5221X
MC13224V 2.4 GHz RF Transceiver Platform in a Package MC13213
CRTOUCHB10VFM Xtrinsic Capacitive and Resistive
Touch-Sensing Platform
Capacitive and resistive touch sensing with gesture recognition to allow
zoom and rotation
MPR03x Touch Sensor 2- or 3-pad touch sensor Xtrinsic Touch Sensing Software
MPC17C724 H-Bridge Motor Drive 0.4 amp, dual h-bridge
MPXx5050 Pressure Sensor 7.5 psi, 50 kPA temperature compensated and calibrated pressure sensor
VF3xx Vybrid Controller Solutions Single-chip solution with Dual XiP Quad SPI, Dual Ethernet and L2 Switch VF4xx, VF5xx
Hospital Admission Machine: Height and Weight
S08JE Flexis 8-bit HCS08 MCU 8-bit ultra-low-power MCU with USB S08JS
MCF5445X ColdFire V2 MCU 32-bit MPU, 10/100 Ethernet, USB OTG MCF5227X
i.MX28x ARM9 Applications Processor 454 MHz ARM9 core, power management, LCD controller, touch screen,
DDR2/mDDR/NAND, Ethernet, USB PHY x2,

Medical Imaging
18.1
Introduction
The complexities of medical imaging require extraordinary processing
and RF power. Modalities, such as magnetic resonance imaging
(MRI), computed tomography (CT) scans and ultrasound all push
the performance limits for advanced integrated I/O, rigorous
data processing, powerful display capabilities and high levels of
connectivity. Many of these needs are addressed by Freescale’s
family of Power Architecture multicore processors, StarCore DSPs
and high-power RF devices.
The Power Architecture family is designed for applications that
require a rich user interface with complex displays and connectivity
options with various standard protocols. StarCore DSPs offer
unprecedented high-processing capacity to support data intensive
applications, such as medical imaging reconstruction. Freescale’s RF
power amplifiers provide the high output power required to achieve
the desired frequency of resonance.
94 Medical Applications User Guide

18.2
Ultrasound
Ultrasound is a non-invasive medical imaging
technique used to visualize muscles, tendons,
pathological lesions and many internal organs
and other structures. It plays an important role
during prenatal care and is commonly used as
a diagnostic tool.
One of the most common uses of ultrasound
is for fetal monitoring. Ultrasound uses sound
waves to create images of a fetus inside
a uterus. Because it uses sound waves
instead of radiation, ultrasound is safer than
X-rays. Gradually, ultrasound has become an
increasingly important part of prenatal care,
providing information that can help the doctor
to plan the monitoring of a pregnant woman,
thus improving the chances of successful
pregnancy.
18.3
How Ultrasound Works
Ultrasound is based on bouncing sound
waves into the body of the developing fetus.
The echoes produced by these waves are
converted into a picture called a sonogram,
which appears on a monitor. This technique is
also often referred to as sonography or sonar.
Propagation and reflection rules that govern
electric signals are also applied to ultrasound.
A transmission line must be terminated in its
characteristic impedance to avoid reflections.
In the equation below, acoustic impedance
Z is a fundamental property of matter and
is related to the density ρ and the velocity
of sound v : Z = ρv. The fraction of energy
R refracted at the normal interface of two
different tissue types is:
R = (Z 2 -Z 1 )
(Z 2 +Z 1 )
2
Figure 18-1: Ultrasound General Block Diagram
Ultrasound
Freescale Technology Optional
18.4
Transducer
The transducer is the element that converts
electrical signals into ultrasound waves. It
consists of a set of transmitter and receiver
transducers arranged in a linear array. A
unique transducer is explained in Chapter
16.6, Fetal Heart Rate Monitor. Pulse trains
are sent by transmitter transducers, and
receiver transducers receive bounced waves.
The operating frequency for this kind of device
is from 5 MHz to 8 MHz.
Medical Imaging
HV Pulse
Transducer DAC
TX Beamformer
Generator
Tx/Rx
Switches
LNA
Signal Conditioning
The blocks needed for signal conditioning/
pulse generator blocks are shown in
Figure 18-3.
18.5
Multiplexer for Tx/Rx
Transducers
This block may be implemented using analog
gates controlled by the MCU/MPU. This
allows the use of transducers as transmitters,
and later the ability to switch the multiplexer
to use as receivers. Multiplexing reduces the
freescale .com/medical 95
VGA
CW (Analog)
Beamformer
AAF
Power
Management
Keypad
DAC
ADC
ADC
User Interface
Spectral
Doppler
Processing
(D Mode)
Display Memory Audio
Output
Figure 17-2: 18-2: Ultrasound Transducer Diagram Diagram
TX
RX
TX
RX
TX
RX
TX
RX
RX Beamformer
RF
Demodulation
B-Mode
Processing
Scan
Conversion
USB
Patient
Beamforming
Control
DSP/DSC
Color
Doppler
(PW)
Processing
(F Mode)
Wireless
Comm

Medical Imaging
number of connections needed, because the
transducers array can range from eight to
more than 256.
18.6
Instrumentation Amplifier
and Variable Gain
Amplifier
Ultrasonic wave energy sent though a
patient’s body is very attenuated by multiple
factors (absorbing, attenuation due to the
medium, inverse square law, etc.). Before
processing information, the instrumentation
amplifier conditions the signal to adequate
levels and eliminates common-mode noise.
A variable gain amplifier is used due to
exponential attenuation of the bounced
waves. Applying an exponential gain reduces
the effect of the attenuation. Figure 18-4
shows the behavior of this element.
Figure 18-5 shows a simple analog
implementation of the circuit (left side). At the
right side, a block diagram of a control system
is shown. This can be implemented by an
MPU using software.
18.7
Beamformer
A beamformer is a device that directs waves
in a specific direction by means of algorithms
that control the transducer array to form
a wave front that generates constructive
interference. This is used to generate the
sweep required to build the image to be
shown. Figure 18-7 is a diagram of the
direction of propagation of waves controlled
by a beamformer.
18.8
Ultrasound Software
Library
The ultrasound software library produces an
ultrasound image from a beamforming signal.
The beam is stored in the memory and passes
through the ultrasound library algorithms to
generate an output image with the specified
height and width.
Figure Figure 17-3: 18-3: Ultrasound Ultrasound Probe Probe Block Block Diagram Diagram
Transducer Array
Figure 18-4: Variable Gain Amplifier Function
Figure 17-4: Variable Gain Amplifier Function
Amplitude
Multiplexer
for TX/RX
Transducers
Instrumentation
Amplifier
High-Voltage
TX Amplifier
Figure 18-5: Analog Implementation of Variable Gain Amplifier
96 Medical Applications User Guide
Gain
Fixed
Gain
Variable Gain
Amplifier
High-Speed
DAC
Time
High-Speed
High-Resolution
ADC
TX
Beamformer
Amplitude
RX
Beamformer
Beamformer
Control
System
Time
To DSP Blocks

The depth in color used in the final image runs
from 0 to 255 where 0 represents the brightest
point and 255 represents the darkest. The
output image from the MSC8156 DSP is
stored in the DDR0 memory.
The MSC8156 DSP is used throughout the
document because the library adapts perfectly
to it. This library is suitable to develop
embedded software for the MSC8156 DSP
which involves working with a beamforming
signal or grayscale output images. Knowledge
in CW IDE and C programming language
is necessary.
The library uses different algorithms to
generate the final output image:
• FIR filter
• Envelope detection
• Log compression
• Histogram equalization
• Speckle noise reduction
• Scan conversion
Key target applications:
• Digital stethoscope
• Medical ultrasonography
• Ultrasonic lithotripsy
Ultrasound Software Library
Reference Design
For more information on how to use the
Ultrasound Software Library, download
Ultrasound Software Library (document
MEDIMGLIBUG) from the Freescale website.
18.9
Microprocessors
MPC5121e
The Freescale MPC5121e integrated
processor uses an e300 CPU core based on
Power Architecture technology. It provides
an exceptional computing platform for
multimedia and is excellent for embedded
solutions with a graphical user interface and
network connectivity.
Figure 17-6: 18-6: Control System Block Block Diagram Diagram
In
To display the processed images received by
the ultrasound probe, this processor includes
the following:
• MBX Lite 2-D/3-D graphics engine licensed
from Imagination Technologies Group Plc.
Includes PowerVR ® geometry processing
acceleration.
• Integrated display controller with support
for a wide variety of TFT LCD displays with
resolution up to 1280 × 720 at a maximum
refresh rate of 60 Hz and a color depth up
to 24 bits per pixel.
Variable Gain
Amplifier
Extracted
Output Signal
Medical Imaging
Figure 18-7: Concentrated Enegry Diagram of a Beanformer
Figure 17-7: Concentrated Energy Diagram of a Beamformer
X
Key Features
• e300 core built on Power Architecture
technology
• Up to 400 MHz performance and 760 MIPS
• AXE, a 32-bit RISC audio accelerator
engine
• PowerVR MBX Lite 2-D/3-D graphics
engine (not included in the MPC5123)
• DIU integrated display controller supports
up to XGA resolution
• 12 programmable serial controllers (PSC)
freescale .com/medical 97
Z
G
H
Out
Y

mobileGT Products
Medical Imaging
The MPC5121e and MPC5123 are the latest
addition to the mobileGT family of processors.
Freescale is working closely with mobileGT
alliance member companies to provide
widespread firmware and software driver
support.
K50 Measurement MCUs
The K50 MCU family is pin, peripheral and
software compatible with other Kinetis MCUs
and provides designers with an analog
measurement engine consisting of integrated
operational and transimpedance amplifiers
and high-resolution ADC and DAC modules.
The family also features IEEE 1588 Ethernet
and hardware encryption, full-speed USB
2.0 On-The-Go with device charger detect
capability and a flexible low-power segment
LCD controller with support for up to 320
segments. Devices start from 128 KB of flash
in 64-pin QFN packages extending up to
512 KB in a 144-pin MAPBGA package.
Key Features
Kinetis K50 MCU features and peripherals in
the integrated measurement engine:
• Ultra-low-power operation
• 2x OPAMP
• 2x TRIAMP
• 2x 12-bit DAC
• 2x 16-bit SAR ADC, up to 31 channels with
programmable gain amplifiers (PGA)
• Programmable Delay Block (PDB)
• I2C • USB connectivity
• ARM Cortex-M4 core with DSP instructions
MCF51MM: Flexis 32-bit
ColdFire V1 MCUs
The MCF51MM256/128 provides ultralow-power
operation, USB connectivity,
graphic display support and unparalleled
measurement accuracy, all in a single 32-bit
MCU, allowing designers to create more
fully featured products at lower cost. The
MCF51MM256/128 is ideal for medical
applications or other applications requiring a
Figure 18-8: Ultrasound Library Flow
Figure 17-8: Ultrasound Library Block Diagram
Beamforming Process
Digital Signal
Filter
Figure 18-9: Kinetis K50 Family Block Diagram
Figure 17-9: Kinetis K50 Family
Security
and Integrity
Cyclic
Redundancy
Check (CRC)
Random
Number
Generator
Cryptographic
Acceleration
Unit (CAU)
Core
ARM ® Cortex-M4
72/100 MHz
Debug
Interfaces
Interrupt
Controller
Standard Feature
System Memories
Internal and
External
Watchdogs
Memory
Protection Unit
(MPU)
Xtrinsic
Low-Power
Touch-Sensing
Interface
Segment
LCD Controller
98 Medical Applications User Guide
DSP
Analog
16-bit
ADC
PGA
Analog
Comparator
6-bit
DAC
12-bit
DAC
Voltage
Reference
OPAMP
TRIAMP
Envelope
Detection
Image Enhancement
Histogram
Equalization
DMA
Low-Leakage
Wake-Up Unit
Timers
FlexTimer
Carrier
Modulator
Transmitter
Programmable
Delay Block
Periodic
Interrupt
Timer
Low-Power
Timer
Independent
Real-Time
Clock (IRTC)
IEEE ® 1588
Timer
Optional Feature
Noise Filter
(speckle)
2D Image Forming
Log
Compression
Program
Flash
(128 to 512 KB)
FlexMemory
(32 to 256 KB)
(2 to 4 KB EE)
Serial
Programming
Interface
(EZPort)
SRAM
(32 to 128 KB)
External
Bus Interface
(FlexBus)
Clocks
Phase-Locked
Loop
Frequency-
Locked Loop
Low/High-
Frequency
Oscillators
Internal
Reference
Clocks
Communication Interfaces HMI
I 2 C
UART
(ISO 7816)
SPI
IEEE 1588
Ethernet MAC
Scan
Convention
I 2 S
Secure
Digital Host
Controller
(SDHC)
USB OTG
(LS/FS)
USB Charger
Detect (DCD)
USB Voltage
Regulator
B-Mode Ultrasound
Brightness
GPIO

significant amount of precision analog such as
instrumentation and industrial control.
The MCF51MM256/128 is part of the
Freescale Flexis MCU series.
Features:
• ColdFire V1 core delivering a 50 MHz core
speed and 25 MHz bus speed
• Up to 256 KB flash and 32 KB SRAM
• Low-power stop 2 current: 500 nA
(32 KB of active SRAM)
• 2 x general purpose opamps
• 2 x transimpedance amplifiers
• 16-bit SAR high resolution analog-to-digital
converter (ADC)
• Analog Comparator with 5-bit digital-toanalog
converter (DAC)
• Internal voltage reference
• USB – device/host/on-the-go controller
• 2 x serial peripheral interface (SPI),
2 x serial communication interface (SCI)
and 1 x I2C • Mini FlexBus (external bus interface EBI)
• Included in Freescale’s Product Longevity
Program
S08MM: Flexis 8-bit MCUs
The 9S08MM128/64/32 provides ultra-lowpower
operation, USB connectivity, graphic
display support and unparalleled measurement
accuracy, all in a single 8-bit MCU, allowing
device designers to create more fully featured
products at a lower cost. It is ideal for
applications requiring a significant amount of
precision analog.
The 9S08MM128/64/32 is part of Freescale’s
Flexis MCU series.
Features:
• S08 core delivering a 48 MHz core speed
and 24 MHz bus speed
• Up to 128 KB flash and 12 KB SRAM
• Low-power stop 2 current: 450nA
(12 KB of active SRAM)
• 2 x OPAMP- General purpose opamps
• 2 x TRIAMP- Transimpedance amplifiers
• 16-bit SAR analog-to-digital converter (ADC)
– high resolution ADC
• Analog comparator
• Internal voltage reference
Figure 18-10: MCF51MM256 Block Diagram
Figure 17-10: MCF51MM256 Block Diagram
2x OPAMP
2x TRIAMP
PDB
MCG
Figure 18-11: MC9S08MM128 Block Diagram
Figure 17-11: MC9S08MM128 Block Diagram
2x OPAMP
2x TRIAMP
PDB
MCG
VREF TOD
PRACMP CMT
VREF TOD
PRACMP CMT
8-bit 9S08 48 MHz Core
Medical Imaging
2 x 4-ch. TPM with PWM 2 x SPI
2 x KBI 2 x SCI
32-bit V1 ColdFire 50 MHz Core with MAC
16-bit SAR ADC I2 12-bit DAC LVI
C
2 x 4-ch. TPM with PWM 2 x SCI
2 x KBI 2 x SPI
Up to 68 GPIO/
16 RGPIO
16-bit SAR ADC I2 12-bit DAC LVI
C
MiniBus External
USB
Device/Host/
OTG
Bootloader
256 KB 32 KB SRAM
USB ROM
Up to 68 GPIO
USB
Device
Bootloader
128 KB Flash 12 KB SRAM
USB ROM
freescale .com/medical 99

• USB device controller
Medical Imaging
• 2 x serial peripheral interface (SPI),
2 x serial communications interface (SCI)
and 1 x I2C Digital Signal Processors
Image reconstruction and processing can
be best realized on Freesacale’s single- or
multicore DSPs. These devices are capable of
performing the data-intensive B mode image
reconstruction and the different modes of
Doppler processing, all of which are integral
parts of any ultrasound system. In addition,
these DSPs are ideal for running other signal
processing functions, such as filtering,
demodulation and scan conversion, to achieve
the desired output image.
MSC815x and MSC825x StarCore-based,
DSP families feature the SC3850 core running
at 1 GHz and delivering up to 48 GMACs
per device. All the devices featured are pin
compatible, allowing system scalability from
one to six cores.
Freescale’s multicore DSP devices offer
unprecedented I/O and memory bandwidth
with the ability to combine Serial RapidIO ® ,
Gigabit Ethernet and/or PCI Express, typically
used for high bandwidth FPGA connectivity.
One or two 64-bit DDR2/3 interfaces will
support the most data-intensive applications,
such as medical image reconstruction.
MSC815x device family also features a
dedicated DFT/FFT hardware accelerator
capable of running up to 350 Mega samples/
sec. Offloading these functions from the
Table 18.1 Freescale’s StarCore SC3850-Based
Digital Signal Processors
MSC8151 Single-core DSP, 8GMAC, FFT/DFT
accelerator
MSC8152 Dual-core DSP, 16GMAC, FFT/DFT
accelerator
MSC8154 Quad-core DSP, 32GMAC, FFT/DFT
accelerator
MSC8156 Six-core DSP, 48GMAC, FFT/DFT
accelerator
MSC8251 Single-core DSP, 8GMAC, PCIe,

All the devices featured are pin compatible,
allowing system scalability from one to
six cores.
Freescale’s multicore DSP devices offer
unprecedented I/O and memory bandwidth with
the ability to combine Serial RapidIO, Gigabit
Ethernet and/or PCI Express, typically used for
high bandwidth FPGA connectivity. One or two
64-bit DDR2/3 interfaces will support the most
data-intensive applications, such as medical
image reconstruction.
The MSC815x device family features the MAPLE
hardware accelerator with dedicated DFT/FFT
functions capable of running up to 350 Mega
samples/sec. Offloading these functions from
the cores leaves ample processing headroom
for additional system requirements or enables
the use of single- or dual-core devices (such as
the MSC8151 and MSC8152 DSPs).
The MSC825x family features one to six
DSP SC3850 cores without the hardware
accelerator for maximum flexibility in algorithm
implementation and improved power efficiency.
Digital Signal Processor Products
16-bit StarCore-based DSPs
• StarCore SC3850 (MSC815x)
• StarCore SC3400 (MSC8144)
• StarCore SC140 (MSC811x, MSC812x)
• StarCore SC1400 (MSC711x, MSC712x)
24-bit general purpose DSPs
• MC56F81xx/83xx
• MC56F80xx
Digital signal controllers
• 56800/E
• MC56F82xx
• MC56F84xx
Figure Figure 17-13: 18-13: General General Analog Analog Configuration Configuration
Core
Memory
256 KB Flash
FlexMemory
32 KB Flash or
2 KB EEPROM
32 KB SRAM
DAC
1-ch./12-bit
56800EX
100 MHz
High-Res
PWM
8-ch. +
PWM 4-ch.
X-Ray
Emissor
Medical Imaging
Figure 18-15: MC56F84xx Digital Signal Controller
MC56F84xx
System Communication
4-ch. DMA 3x UART
3x SPI
CAN
2x I
EOnCE (Debug Module)
JTAG
2 Memory Resource
Protection Unit
Quadrature Decoder
CRC
C/SMBus
Voltage Regulator
Internal Watchdog
Clocks and Timer
freescale .com/medical 101
PWM
12-ch.
External Watchdog
Inter-Module Cross Bar
4x Analog
CMP
+ 6-bit DAC
Photo
Detector Grid
MUX
Figure 18-14: Photo Detector Configuration
Figure 17-14: MC9S08MM128 Block Diagram
Transimp
Amp
2x HS ADC
8-ch./12-bit
with PGA
ADC
Timers
SAR ADC
16-ch./16-bit

Medical Imaging
18.14
Capacitive Sensing and
Touch Screen Display
The MC34940 is intended for cost-sensitive
applications where non-contact sensing
of objects is desired. When connected to
external electrodes, an electric field is created.
The MC34940 detects objects in this electric
field. The IC generates a low-frequency sine
wave, which is adjustable by using an external
resistor and is optimized for 120 kHz. The
sine wave has very low harmonic content to
reduce harmonic interference. The MC34940
also contains support circuits for an MCU to
allow the construction of a two-chip E-field
system.
For more information about touch panel
applications, see the application note titled
Touch Panel Applications Using the MC34940/
MC33794 E-Field IC (document AN1985),
available at freescale.com.
For wireless communication, power
management, keypad and speaker
implementation modules, see Chapter 3
Telehealth Systems Introduction.
Table 18.2: FFT/DFT Hardware Accelerator Features
Standard Compliance Data Rates Comments
FFT sizes: 128, 256, 512, 1024, 2048 FFT2048: Up to 280 Mega samples/sec Advanced scaling options
points
FFT1024: Up to 350 Mega samples/sec Guard bands insertion in iFFT
DFT sizes: Variable lengths DFT/IDFT
processing of the form 2 k ·3 m ·5 n ·12, up
to 1536 points
DFT: Up to 175 Mega samples/sec
Table 18.3: MSC815x and MSC825x Family Comparison Chart
Device 8156 8154 8152 8151 8256 8254 8252 8251
SC8350 DSP Cores 6 4 2 1 6 4 2 1
Core Speed (MHz) 1 GHz 1 GHz 1 GHz 1 GHz 1 GHz
800 MHz
Core Performance (16-bit
MMACs)
Table 18.4: Freescale Technologies for Medical Imaging
1 GHz
800 MHz
1 GHz 1 GHz
102 Medical Applications User Guide
Up to
48000
Up to
32000
Up to
16000
Up to
8000
Up to
48000
Up to
32000
Shared M3 Memory 1 MB 1 MB
I-Cache (per core) 32 KB 32 KB
D-Cache (per core) 32 KB 32 KB
L2 I-Cache (per core) 512 KB 512 KB
DDR2/3 2 (800 MHz) 2 (800 MHz)
PCIe 1 1
GEMAC (RGMII, SGMII) 2 2
sRIO 2 2
TDM 4 4
SPI 1 1
UART 1 1
I 2 C 1 1
FFT/DFT Accelerators 1
Proc. Tech. 45 nm SOI 45 nm SOI
Package 783 Ball
FC-PBGA
Device Description Key Features Alternate Options
Ultrasound Imaging
MPC5121e 32-bit Power Architecture ® MCU 400 MHz e300 core and 760 MIPS built on
Power Architecture
i.MX53 ARM ® Cortex-A8 Applications Processor i.MX53 ARM Cortex-A8 Applications Processor
1GHz ARM Cortex A8, DDR3, Ethernet, 720P
Encode/1080P Decode, 2D/3D Graphics
MSC8156 Six-Core High-Performance DSP Digital signal controller, built on multicore
StarCore DSP
783 Ball
FC-PBGA
MPC8536E, MPC5125, MPC83xx
i.MX28x, i.MX 6 Series
MSC8154, MSC8152
MPR03x Touch Sensor 2 or 3-Pad touch sensors Xtrinsic Touch Sensing Software
MC13224V 2.4 GHz RF Transceiver Platform in a Package MC13213
Digital X-Ray
i.MX28x ARM9 Applications Processor 454 MHz ARM9 core, power management, LCD
controller, touch screen, DDR2/mDDR/NAND,
Ethernet, USB PHY x2,

Summary
Summary
Applications Freescale Productus Freescale Differentiators
Home Portable
Blood Pressure Monitor
(BPM)
Diabetes Care (blood
glucose monitor and
insulin pumps)
Digital Scale
Digital Thermometer
Heart Rate Monitor (HRM)
Pulse Oximetry
Telehealth/Telemonitoring
Diagnostics and Therapy
Ablation Laser
Anesthesia Unit Monitors
Clinical Patient Monitoring
Clinical/Surgical Equipment
Defibrillators/AEDS
Dialysis Equipment
Electrocardiogram (ECG
or EKG)
Electromyograph
Fetal Heart Rate Monitor
Fitness/Wellness
Hospital Admission
Machines
Implantable Devices
Infusion Pumps
RF Ablation
Ventilator/Respirators
Wound Management
Imaging
Bone Densitometer
Computed Tomography (CT)
Fluoroscopy, Angiography
Magnetic Resonance
Imaging (MRI)
Positron Emission
Tomographer (PET)
Ultrasound
X-Ray and Related
Applications
Flexis families (8- and 32-bit)
- MC9S08MM, MCF51MM: Medical-oriented MCUs
- MC9S08QE, MCF51QE: general purpose, low power
- MC9S08JM, MCF51JM: USB, low power
- MC9S08AC, MCF51AC: FlexTimer
8-bit MCUs
- MC9S08LL: low power, segment LCD
- MC9S08JS: low power, USB
Ultra-low-end 8-bit MCUs
- MC9RS08KA: general purpose
- MC9RS908LA, MC9RS08LE: segment LCD controllers
ColdFire technology
- MCF5225x: 32-bit, USB, Ethernet
Kinetis ARM Cortex-M4 family: MK10, MK20, MK40, MK50
i.MX series (ARM core, 32-bit)
- i.MX233: USB, LCD controller with touch screen
- i.MX28x: power management, LCD controller with touch screen, USB, Ethernet
Wireless: MC1322x (IEEE ® 802.15.4/ZigBee ® technology)
Pressure sensors: MPL3115A2, MPX2300DT1, MPXV5050GC6, MPXM2053GS (blood
pressure monitoring)
Touch sensors: MPR03x, MPR121QR2, Touch-Sensing Software IP
Accelerometers: MMA8451Q, MMA8452Q, MMA8453Q (arm angle detection for blood
pressure monitoring), MMA8451Q, MMA8452Q, MMA8453Q (portrait/landscape)
Power management: MPC18730, MC13883, MC3467x, MC34704, MC13892
Motor drivers (H-bridges): MC33887, MPC17511, MPC17C724, MC33931,
MC33932, MC33926
LED backlight: MC34844, MC34845
Flexis family: Low-end to high-end pin-to-pin compatibility, 8- and 32-bit
ColdFire technology: MCF5225x 32-bit, USB, Ethernet
Digital signal controllers (DSCs): MC56F801x, MC56F802x, MC56F8100, MC56F8300
Kinetis ARM Cortex M4 family: MK40, MK50, MK60
i.MX Series (ARM core, 32-bit)
−i.MX287: power management, LCD controller with touch screen, USB, Dual Ethernet
−i.MX357: adds graphics
−i.MX53: adds video
−i.MX 6 Series: adds multicore
High-performance 32-bit MPUs: MPC5121e, MPC8377, MPC8641, MPC8535, P1022,
P1013
Wireless: MC1322x (IEEE 802.15.4/ZigBee technology)
Pressure sensors: MPL3115A2, MPXV5004G, MPXV4006G, MPXC2011DT1, MPX12GS,
MPX5010DP, MPX2010DP, MPXV2053GVP, MPXV5100G, MPX2300DT1
Touch sensors: MPR03x, MPR121QR2
Accelerometers: MMA8451Q, MMA8452Q, MMA8453Q
Power management: MPC18730, MC13883, MC13892, MC34700, MC34712, MC34713,
MC34716, MC34717
Motor drivers (H-bridges): MC33887, MPC17511, MPC17C724
LED backlight: MC34844, MC34845
Radio frequency (RF) LDMOS power transistors: MRF6VP41KH, MRF6S24140H,
MRF6P24190H
E Series high-power enhanced ruggedness RF amplifiers: MRFE6VP100H, MRFE6VS25N,
MRFE6VP5600H, MRFE6VP6300H, MRFE6VP61K25H, MRF6VP8600H
High performance: MPC837x, MPC831x, MPC85xx, P2020
High-end image processing: MPC512x, MPC8610, MSC8122, MSC8144, MPC8536,
MPC8315, MSC8144, MAC8154, MSC8156, P1022
i.MX series (ARM core)
−i.MX357: 32-bit, LCD, USB, Ethernet, video and camera
−i.MX53: 32-bit, video, graphics, Ethernet, LCD with touch screen, USB
Wireless: MC132xx ZigBee technology
Accelerometers: MMA8451Q, MMA8452Q, MMA8453Q (vibration sensing)
Touch sensors: MPR03x, MPR121QR2
Power management: MPC18730, MC13883, MC13892, MC34704, MC34712,
MC34713, MC34716, MC34717
LED backlight: MC34844, MC34845
General purpose amplifiers
High-power RF amplifiers: MRF6VP41KH, MRF6S24140H, MRF6P24190H
E Series high-power enhanced ruggedness RF amplifiers: MRFE6VP100H,
MRFE6VS25N, MRFE6VP5600H, MRFE6VP6300H, MRFE6VP61K25H,
MRF6VP8600H
Product differentiators
• Highest quality standards
• Product life: 15-year longevity
• MC9S08QE, MC9S08LL: low power consumption to enable longer
battery life
- 370 nA, 1.8V, 6 usec wake up in lowest power mode
• MC9S08LL: superior LCD controller IP
• Connectivity: USB, ZigBee
• Pressure sensors: packaged specifically for medical applications
• High-end MPUs with graphics acceleration
Solution differentiators
• Solutions that enable a lower system cost
• Touch U/I suited for sterile hand-held monitors
• Cost-effective, amplified, small form factor sensors with high
sensitivity
• USB for medical: Continua ready, IEEE compliant PHDC USB
software stack available
Product differentiators
• Highest quality standards
• Product life: 15-year longevity
• Breadth and scalability of portfolio
• Low-power solutions
• i.MX series, Flexis, ColdFire: high level of integration
- Connectivity (USB and Ethernet)
- LCD control (graphic and segment)
- Internal memory
- High precision analog
• ColdFire: embedded high-performance digital signal processor
(DSP) functionality with integrated MAC
• i.MX series: video and graphics acceleration
• Strong/comprehensive RF power LDMOS portfolio
- Best ruggedness in the market
- Broadest line of enhanced ruggedness devices
- Exceptional efficiency
- Highest gain
Solution differentiators
• Touch U/I suited for sterile clinical equipment
• Cost-effective, amplified, small form factor sensors with high
sensitivity
USB for medical
• Continua ready, IEEE compliant PHDC USB software stack available
Product differentiators
• Highest quality standards
• Product life: 15-year longevity
• Breadth and scalability of portfolio
• Low-power solutions
• i.MX series, Flexis, ColdFire: high level of integration
- Connectivity (USB and Ethernet)
- LCD control
- Internal memory
- High precision analog
• ColdFire: embedded high-performance DSP functionality with
integrated MAC
• i.MX series: video and graphics acceleration
• Strong/comprehensive RF power LDMOS portfolio
- Best ruggedness in the market
- Broadest line of enhanced ruggedness devices
- Highest gain
- Exceptional efficiency
• High-performance processors: PCI Express ® support and Serial
ATA (SATA) for storing images
Solution differentiators
• Touch U/I suited for sterile clinical equipment
• Cost-effective, amplified, small form factor sensors with high
sensitivity
• AltiVec engine for image processing
freescale .com/medical 103

Application Notes
Application Notes
Application Notes
AN2975: IEEE 802.15.4 and ZigBee Applications
AN3231: SMAC Based Demonstration Applications
AN3761: Using Freescale Devices for Contactless Touch Applications
AN3583: Using Low-Power Mode on the MPR083 and MPR084
AN3796: LCD Driver Specification
AN4059: Heart Rate Monitor and ECG Fundamentals
AN4223: Connecting Low-Cost External Electrodes to MED-EKG
AN4115: IrDA Driver and SD Card File System on the MM/JE Flexis Families
AN3460: Low-Power Enabled by QE128 (S08 and MCF51)
AN3465: Migrating within the Controller Continuum
AN1326: Barometric Pressure Measurement using Semiconductor Pressure Sensors
AN1097: Calibration-Free Pressure Sensor System
AN3870: Developing an Application for the i.MX Devices on Linux
AN3632: Using the Touch Screen Controller on the MCF5227x
AN3552: Analog Comparator Tips and Tricks
AN4153: Using Freescale eGUI with TWR-LCD on MCF51MM Family
ANPERIPHQRUG: Quick Reference User Guide for Analog Peripherals on the MM and JE Family
AN3827: Differences Between Controller Continuum ADC Modules
AN3412: Dynamic LCD Driver Using GPIO Pins
AN3949: ADC16 Calibration Procedure and Programmable Delay Block Synchronization
AN2731: Compact Integrated Antennas
AN4318: Histogram Equalization
AN4323: Freescale Solutions for Electrocardiograph and Heart Rate Monitor Applications
AN4325: Spirometer Demo with Freescale MCUs
AN4327: Pulse Oximeter Fundamentals and Design
AN4328: Blood Pressure Monitor Fundamentals and Design
AN4364: Glucose Meter Fundamentals and Design
AN4496: Pulse Oximeter Using USB PHDC
104 Medical Applications User Guide

Appendix
Digital Signal Processing
Concepts
A digital filter is characterized by its transfer
function, or equivalently, its difference
equation. Mathematical analysis of the transfer
function can describe how it will respond to
any input. As such, designing a filter consists
of developing specifications appropriate to
the problem, and then producing a transfer
function which meets the specifications.
Figure A-1: Signal Responses
Figure A-1: Signal Responses
Signal Amplitude
4000
3500
3000
2500
2000
1500
1000
500
0
0
Low Pass Filtered Signal
High Pass Filtered Signal
Input Signal
3000 Hz Sample Rate
1000 2000 3000 4000
Sample Number
5000 6000
Appendix
Low, High and Band Pass Data
1000 2000 3000 4000 5000 6000
Sample Number
Signal Spectrum
freescale .com/medical 105
2500
2000
1500
1000
500
0
-500
-1000
-1500
0
Signal Amplitude
Time
Log(Meg)
40
30
20
10
0
-10
-20
-30
0 500 1000
Sample Number
Figure A-2: Signal Processing for HRM and Pulse Oximetry
Figure A-2: Signal Processing for HRM and Pulse Oximetry
Analog
Low Pass
Filter
Sample
and Hold
ADC
Digital
Filters
P T
Q
R
S
DC/PWM
DC/PWM
Time
Analog
Low Pass
Filter
Analog
Low Pass
Filter
1500

Appendix
Digital Filter Examples
Digital FIR vs. IIR Filters
A digital finite impulse response (FIR) filter can
implement non-realizable analog functions,
with many more multiplies, adds and data
moves.
y(n) =
N-1
a(i)x(n-i)
i=0
A digital infinite impulse response (IIR) filter
provides a digital imitation of analog filters.
It generally has the fewest operations, but is
often 10x more efficient.
y(n) =
N-1
M
a(i)x(n-i) + b(j)y(n-j), M>N
i=0
j=1
Signal Reconstruction
To reconstruct the signal to the original, we
use the digital signal reconstructed by the
DAC and then use passive filters to shape it in
a smooth manner. See Figure A-5.
Figure A-3: Anti-Aliasing Filter and Sampling
Figure A-3: Anti-Aliasing Filter and Sampling
Signal + Noise LPF (Signal + Noise) Numbers that we can
use in DSP techniques
Volts
Volts
Time
Analog
Low-Pass
Filter
Figure A-4: Low- and High-Pass Filters
Figure A-4: Low- and High-Pass Filters
Sample
and Hold
ADC
Sample Rate
Numbers that we can
use in DSP techniques
1.6060e+000
2.4394e+000
2.2457e+000
1.4378e+000
7.7448e-001
7.9937e-001
1.4447e+000
2.0849e+000
2.0000e+000
9.1704e-001
-7.6317e-001
-2.2173e+000
y(n)+0.0732x(n)=0.1464x(n-1)+0.0732x(n-2)
+1.099y(n-1)-0.3984y(n-2)
Figure A-5: Signal Reconstruction
Figure A-5: Signal Reconstruction
1.6060e+000
2.4394e+000
2.2457e+000
1.4378e+000
7.7448e-001
7.9937e-001
1.4447e+000
2.0849e+000
2.0000e+000
9.1704e-001
-7.6317e-001
-2.2173e+000
1.6060e+000
2.4394e+000
2.2457e+000
1.4378e+000
7.7448e-001
7.9937e-001
1.4447e+000
2.0849e+000
2.0000e+000
9.1704e-001
-7.6317e-001
-2.2173e+000
Sample Rate
Sample
and Hold
ADC
Sample Rate
1.6060e+000
2.4394e+000
2.2457e+000
1.4378e+000
7.7448e-001
7.9937e-001
1.4447e+000
2.0849e+000
2.0000e+000
9.1704e-001
-7.6317e-001
-2.2173e+000
106 Medical Applications User Guide
DAC
Volts
Volts
Time
Low Pass
Digital Filters
High Pass
Time
1.6060e+000
2.4394e+000
2.2457e+000
1.4378e+000
7.7448e-001
7.9937e-001
1.4447e+000
2.0849e+000
2.0000e+000
9.1704e-001
-7.6317e-001
-2.2173e+000
1.6060e+000
2.4394e+000
2.2457e+000
1.4378e+000
7.7448e-001
7.9937e-001
1.4447e+000
2.0849e+000
2.0000e+000
9.1704e-001
-7.6317e-001
-2.2173e+000
Analog
Low-Pass
Filter
Reconstruction Filters
Time
Analog
Low-Pass
Filter
Sample Rate
Volts
Volts
DAC
Time
Time

Freescale Technologies
• ColdFire MAC architecture enables DSP
algorithms
• IIR and FIR filters gain performance with
MAC instructions
• Single instruction: Multiply-accumulate with
load
• Multiply two 16-bit word or 32-bit
longword operands
• Add 32-bit product to 32-bit accumulator
(ACC) register
• Load 32-bit longword for next instruction
and increment address register (ptr)
• Sample analog accelerometer data with
ADC (3 kHz)
• Execute two parallel digital filters
• Send via USB: raw and filtered data,
timestamp, filter execution cycles
For more information, download the PDF
ColdFire Technology and DSP from
freescale.com/files/dsp/doc/ref_manual/
CFDSPTechnology_DSP.pdf.
Instrumentation Amplifier
In medical instrumentation it is common
to process signals with a lot of noise and
small amplitude. For these reasons an
instrumentation amplifier, which has high
entrance impedance and high CMRR, is often
used. This device can be built with discrete
elements or can be obtained pre-built. The
amplifier gets the differential between the
signal and amplifier depending on the gain,
which determines the signal amplitude.
The gain recommended for medical
applications is 1000 because the signal
oscillates around 1 mV, and with this gain
the signal can be amplified up to 1V. It is
also recommended that for the first part you
generate a gain of only 10 to avoid amplifier
common-mode signals. Only filter the noise
signals with this part, and amplify the rest of
the signal with the differential amplifier.
A =1+ 1 R2 R1 R +R 1 2
A = 1
R1 R 2 =(A 1 R 1 )-R 1
A 2 = R 4
R 3
R 4 = A 2 R 3
Appendix
Figure A-6: ColdFire Demo Board (M52221 DEMO)
Figure A-6: ColdFire Demo Board (M52221DEMO)
Accelerometer
Mechanical
Oscillator
A 1 = A 1 A 2
Values to obtain a signal around 1V: Low gain: 10, High gain: 100, Total gain: 1000
freescale .com/medical 107
ADC
Timers
Filter 1
Filter 2
USB
Debug
Lab View
ColdFire V2 MCU Laptop Host
Figure A-7: Instrumentation Amplifier Design Diagram
Figure A-7: Instrumentation Amplifier Design Diagram
Vi 1
Vid=
(Vi 1 -Vi 2 )
Vi 2
2R 1
R 2
Vid/2R1 R2 R 3
R 3
Vid(1+2R 2 /2R 1 )
R 4
R 4
Vo=R 4 /R 3 ( 1+R 2 /R 1 )Vid
A=Vo/Vid

Appendix
Analog Measurement
Engine
Some of the analog modules are commonly
used in most of the medical applications.
Therefore, it is necessary to add them in the
design separately, which increases the
PCB size and increases the cost. Freescale
medical-oriented solutions embed these
modules—reducing PCB size, cost and
increasing the design performance. Modules
included in the analog measurement engine
are: OPAMP, TRIAMP, ADC, DAC, ACMP, VREF
and PDB. These modules are explained below.
OPAMP
Operational amplifiers (OPAMPS) have several
purposes. They can be configured as simple
as a buffer circuit or as complex as an N order
filter, OPAMPS have a huge application field in
the medical industry.
Freescale medical oriented MCUs integrate
operational amplifiers on chip. These OPAMPS
can be configured to work as general purpose
OPAMPS, buffer circuit or configurable gain
inverting and non-inverting amplifiers.
TRIAMPS
Transimpedance amplifiers (TRIAMP) are
special general purpose OPAMPS with
reduced input offset voltage and bias current,
ideal for applications which requires low
amounts of voltage and current. TRIAMPS
can be also used as general purpose OPAMPS
to reduce BOM and PCB size.
ACMP
Analog comparators (ACMP) compare two
analog inputs and generate a high or low
state depending on the input values. Output
is high when the positive input is greater than
the negative input and low when the negative
input is greater than the positive input. Analog
comparators can be constantly checking the
value of both inputs and generate an interrupt
when a change occurs.
Figure A-8: Test Strip Basic Block Diagram Using Flexis MM
Figure A-8: Test Strip Basic Block Diagram Using Flexis MM
Blood
Sample
Reactive
Electrode
External
Components
Embedded
Transimpedance
Amplifier
Figure A-9: Kinetis K50 Family Block Diagram
Figure A-9: Kinetis K50 Family
Security
and Integrity
Cyclic
Redundancy
Check (CRC)
Random
Number
Generator
Cryptographic
Acceleration
Unit (CAU)
Core
ARM ® Cortex-M4
72/100 MHz
Debug
Interfaces
Interrupt
Controller
Standard Feature
MCU/MPU
System Memories
Internal and
External
Watchdogs
Memory
Protection Unit
(MPU)
Embedded
ADC
Xtrinsic
Low-Power
Touch-Sensing
Interface
Segment
LCD Controller
Kinetis K50 Family of MCUs can provide up to 31 16-bit ADC channels
108 Medical Applications User Guide
DSP
Analog
16-bit
ADC
PGA
Analog
Comparator
6-bit
DAC
12-bit
DAC
Voltage
Reference
OPAMP
TRIAMP
DMA
Low-Leakage
Wake-Up Unit
Timers
FlexTimer
Carrier
Modulator
Transmitter
Programmable
Delay Block
Periodic
Interrupt
Timer
Low-Power
Timer
Independent
Real-Time
Clock (IRTC)
IEEE ® 1588
Timer
Optional Feature
Program
Flash
(128 to 512 KB)
FlexMemory
(32 to 256 KB)
(2 to 4 KB EE)
Serial
Programming
Interface
(EZPort)
SRAM
(32 to 128 KB)
External
Bus Interface
(FlexBus)
Clocks
Phase-Locked
Loop
Frequency-
Locked Loop
Low/High-
Frequency
Oscillators
Internal
Reference
Clocks
Communication Interfaces HMI
I 2 C
UART
(ISO 7816)
SPI
IEEE 1588
Ethernet MAC
I 2 S
Secure
Digital Host
Controller
(SDHC)
USB OTG
(LS/FS)
USB Charger
Detect (DCD)
USB Voltage
Regulator
GPIO

ADC
Analog-to-digital converters (ADC) are one of
the most important modules on the medical
and overall electronics field. This module
allows the conversion of an analog input
into a digital value that can be processed
by a MCU or MPU. ADCs output an N-bits
value as a result of the conversion, and can
take significant amount of PCB size placed
separately. Embedded ADCs reduce PCB size
and processing efforts reducing the access
time to the result value.
DAC
The digital-to-analog converter (DAC)
generates an analog voltage depending on
the value in its input register and the module
resolution. DACs are useful in the generation of
reference voltages or as wave form generators.
Electrocardiography uses DACs for ECG
baseline adjustment.
PDB
The programmable delay block (PDB) provides
controllable delays from either an internal
or an external trigger, or a programmable
interval tick, to the hardware trigger inputs of
ADCs and/or generates the interval triggers
to DACs, so that the precise timing between
ADC conversions and/or DAC updates can
be achieved. The PDB can optionally provide
pulse outputs (pulse-outs) that are used as the
sample window in the Analog Comparator.
VREF
VREF module generates a static voltage that
can be used as a reference on an OPAMP,
DAC, ACMP or other application without
need of external regulators. Embedded VREF
modules are programmable and can reduce
the amount of external components on a PCB
eliminating the need of external regulators or
voltage dividers for VREF applications.
Table A-1: Filters for Medical Applications
Appendix
Type Circuit Cut frequency Equation
Band-pass
passive
Reject-band
passive
0.1 Hz–150 Hz
Heart operating range
40 Hz–60 Hz
Noise signal
from the line
Band-pass active 400 Hz–4 KHz
Sound wave
bounced (range
depends of the
transducer)
Low-pass active 150 Hz
Heart operating range (if
the passive filter is not
enough, use an active
filter)
High-pass filter
active
Filter Design
A lot of noise is present in biophysical signals.
To attenuate this noise, low pass filters and
high pass filters are used to amplify the small
AC components and reject DC components.
The filters allow only the useful signals, which
helps to attain a more accurate diagnosis.
These filters can be built with passives
or actives (op amps) depending on the
application, although active filters are more
effective at rejecting noise. Passive filters are
more cost-effective and are suitable in some
cases. Sometimes the MCU does not have a
DAC. This can be built by the PWM module
and external low pass filter to convert digital
data to analog data.
Some medical applications
Not specific
freescale .com/medical 109

Appendix
Figure A-10: Applications Based on Medical Specialties
110 Medical Applications User Guide

freescale .com/medical

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