Bayer HealthCare RapidPoint 400 Series, Руководство по обслуживанию, Страница: 83 / 458

Rev. C Electronic System Overview 83
Main PC Board
The Main PC board provides the following:
• system requirements for user interface processing
• real-time processing
• user/real-time first-in-first-out (FIFO) communications
• data acquisition
• control and utility functions
Real-Time Processor (RTP)
RTP 68332 Processor Circuitry
U47 is a 68332 32-bit microprocessor based on the 68000 core CPU32. It
has additional functionality such as memory chips selects and extensive
timer-counter functions.
The data bus, DR0 to DR15, has 32 bits internally and 16 bits externally.
This bus is separated into a fast local bus for memory and a slower buffered
bus for all other devices on the Main board.
The microprocessor uses a frequency synthesizer, Y1, for generating both
its internal and external system clock.
U55 is a power supervisor and watchdog. The output pin 11 of the
integrated circuit (IC) provides the microprocessor with a correctly
generated, active low reset pulse. Pin 11 monitors the 5 V power on pin 15
and generates a reset if the voltage does not remain within the specified
+5% tolerance range. Pin 2 of IC U55 is the asynchronous active low reset
input.
RTP 68332 Address and Data Bus Circuitry
The 68332 data bus, DR0 to DR15, is pulled up to VCC through resistor
pack RN23. The exception is DR3, which is actively pulled to ground during
RTP system reset by probe CR17.
Data bus, DM0 to DM15, is conditioned and passed to the memory section
and to data bus drivers U49 and U58.