Medical Applications User Guide (pdf) - Freescale Semiconductor

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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
Page 1 and 2: Medical Applications User Guide TM
Page 3 and 4: freescale.com/medical 3 Introductio
Page 5 and 6: Introduction 1.1 Freescale Offers T
Page 7 and 8: Monebo Kenetic ECG Algorithms Free
Page 9 and 10: Home Portable Medical 2.1 Introduct
Page 11 and 12: 3.2 Home Health Hub (HHH) Reference
Page 13 and 14: 3.3 Power Management Every design n
Page 15 and 16: MC34704 The MC34704 is a multi-chan
Page 17 and 18: 3.7 How it Works The external capac
Page 19 and 20: eliably monitor and manage non-crit
Page 21 and 22: 3.19 Standard Medical USB Communica
Page 23 and 24: Freescale has developed sample code
Page 25 and 26: 4.2 Heartbeat Detection The heartbe
Page 27 and 28: 4.6 Blood Pressure Monitor Referenc
Page 29 and 30: MCF51MM: Flexis 32-bit ColdFire V1
Page 31 and 32: Heart Rate Monitor 5.1 Introduction
Page 33 and 34: Instrumentation amplifier requireme
Page 35 and 36: 6.2 Test Strip A test strip consist
Page 37 and 38: fully featured products at lower co
Page 39 and 40: Freescale’s Xtrinsic acceleromete
Page 41: 7.2 Signal Acquisition This applica
Page 45 and 46: 8.2 Electrocardiography (ECG) Acqui
Page 47 and 48: Xtrinsic Touch-Sensing Software Xtr
Page 49 and 50: • Internal voltage reference •
Page 51 and 52: 9.2 Microphone Amplifier The microp
Page 53 and 54: 9.5 Digital Signal Processor The di
Page 55 and 56: Diagnostic and Therapy Devices 10.1
Page 57 and 58: 10.4 Filtering ECG The ECG has thre
Page 59 and 60: Features: • ColdFire V1 core deli
Page 61 and 62: The eMAC improvements target three
Page 63 and 64: 11.2 Circuit for Capacitive Dischar
Page 65 and 66: 12.2 System Sensors Figure 12-1: Ve
Page 67 and 68: • i.MX Processors The most versat
Page 69 and 70: MPX230xDT1: High Volume Pressure Se
Page 71 and 72: S08MM: Flexis 8-bit MCUs The 9S08MM
Page 73 and 74: 13.2 Brief Theory As mentioned in C
Page 75 and 76: Vital Signs 14.1 Introduction A vit
Page 77 and 78: 14.6 Motor Control with Freescale D
Page 79 and 80: State-of-the-art technology—inclu
Page 81 and 82: 15.5 Communication Interfaces USB P
Page 83 and 84: 15.7 Multimedia Applications with i
Page 85 and 86: 16.2 Ultrasonic Probe The ultrasoni
Page 87 and 88: segments. Devices start from 128 KB
Page 89 and 90: Powered Patient Bed 17.1 Introducti
Page 91 and 92: accelerometer is required. The Free
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Table 17-1. Freescale Technologies
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18.2 Ultrasound Ultrasound is a non
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The depth in color used in the fina
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significant amount of precision ana
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All the devices featured are pin co
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Summary Summary Applications Freesc
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Appendix Digital Signal Processing
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Freescale Technologies • ColdFire
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ADC Analog-to-digital converters (A
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freescale .com/medical
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Medical Applications User Guide (pdf) - Freescale Semiconductor

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