Service manual

CARDELL MONITOR SERVICE MANUAL
21-02-0286 REV. 02 05/09
57
Power ON/OFF and Reset to Digital Signal Processor Controller
The Power switch comes into the Main Control Board at keypad connector J6. It is read as an
input pin to the Supervisor (U5 pin 21).
The Supervisor has an output pin (U5 pin 7) that controls the reset to the DSP (U20).
Monitor ON/OFF (+5V ENABLE)
The monitor turning on and off is control by an output pin of the Supervisor (U5 pin 11) and
associated components Q1 and Q2.
Communication with Digital Signal Processor Controller
The Supervisor (U5) has two-way communication to the DSP (U20) using a dedicated SPI line.
Monitor Battery Charger and Battery Conditions
The DC input and Battery inputs are read by two analog to digital converter of the Supervisor
(U5 pins 2 and 3). The results of these signals are used to control the Low and Dead Battery
conditions of the monitor and the status of the front panel Power / Charging LED (LED 1).
Two output lines from the Battery Charger Control chip (U8) are read by the Supervisor (U5 pins
23 and 24). The information from these pins informs the Supervisor the status of the charging
condition (fast charge, trickle charge or hold off). All of the information is sent from the
Supervisor to the DSP (U20) thru the SPI port.
DIGITAL SIGNAL PROCESSOR CONTROLLER
The Motorola DSP56F827, is Digital Signal Processor (DSP U20) and is the Main Controller of
the CARDELL Monitor. The controller has 64K of program flash, 4K of data flash, 1K program
ram, 4K of data ram and operates off an external 4 MHz crystal. The DSP features are PLL, 2
SPI ports, TOD, watchdog timer, quad timer, 16 dedicated I/O, 48 shared I/O, 64 muxed I/O,
interrupt controller, 8 programmable chip selects and 32 external bus signals.
SpO
2
Monitoring
The SpO
2
Module is an option that is plugged into the Main Control Board, J3 for Nellcor and
Nonin. The isolated power supply for the SpO
2
Module circuit (+5V_ISO2) is controlled by an
output pin of the DSP (U20 pin 37). The Module is read by the DSP (U20) thru the serial port
(TXD2 and RXD2) and associated components (U10, Q9, Q10, ISO1 and ISO2). The power is
turned off when the SpO
2
option is not installed.
Blood Pressure Monitoring
The Blood Pressure Module is plugged into J4 of the Main Control Board. The power (+VND) of
the Blood Pressure Module is controlled by an output pin of the DSP (U20 pin 36). The Blood
Pressure Module is read by the DSP (U20) thru the serial port (TXD1 and RXD1).
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