Medical Applications User Guide (pdf) - Freescale Semiconductor

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
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82 Medical Applications User Guide
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Figure 14-10: 15-10: Ethernet Interface Circuitry
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