Smiths Medical BCI 3304, Service Manual

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Chapter 2: Oximeter Circuit Description
3304 Service Manual 2-7
Signal Dictionary
This section lists in alphabetical order the signal names used on the
schematics. The signal’s origin, destination, and purpose are described.
Oximeter Board
SIgnAL DeSCRIPTIOn
/ADCRST Reset signal to ADC.
/AMB Signal informing microprocessor about excess of ambient light.
/BLANK Signal used to shut down power supply and display board
during data acquisitions.
/BUSRQ,
/BUSAK
Microprocessor bus access signals used by U11 to access ROM
and RAM.
/DINT Interrupt signal from master microprocessor to the slave
microprocessor
/DWR,
/DRD,
/BMS,
/DMS
Signals used by the slave Digital Signal Processing
microprocessor to control memory access.
/HALT Signal used by microprocessor to turn power off.
/INT1 /INT1 is used to inform microprocessor that power control flip-
flop U19A - A19B was switched to the power off condition, and
power will disappear soon.
/IO1 Strobe to U20 to read input data and to U21 and U22 to latch
output data.
/IO2 =
/HOLD
ADC strobe signal, starts data conversion.
/IO3 Strobe to U29 to latch output data.
/RD, /WR,
/ME, /IOE
Signals used by master microprocessor to control memory and
peripheral devices.
/RESET Microprocessor and peripheral devices reset signal.
A0-A16 A0 through A16 are the microprocessor’s address lines. A0-A16
are used to address the RAM, PROM, and I/O ports.
A18 =
TONE
Microprocessor output A18 (TOUT) is configured as a timer
output and controls the tone of the optional pulse beep speaker.
ADC-RDY Input signal indicating that ADC is ready for the next conversion.
ANA+5 The +5 volt power supply VCC is filtered to produce ANA+5.
ANA+5 powers the analog circuitry.