BCI Capnocheck Plus - Signal Dictionary and Main Board Details

Chapter 3: Capnocheck Plus Circuit Description
Signal Dictionary
This section lists, in alphabetical order, the signal names used on the
schematics. The signal’s origin, destination, and purpose are described.
Main Board
SIGNAL DESCRIPTION
AO-A17 AO through A17 are the microprocessors address lines. A0-A17 are used
to address the RAM, PROM, and VO ports.
A18 = TONE Microprocessor output A18 (TOUT) is configured as a timer output and
controls the tone of the optional pulse beep speaker.
ACHO-ACH2 Three analog output signals.
ADCCLK ADC clock frequency of 1.152MHZ.
JADCS Signal used to select ADC.
ADDI
Synchronous communication input data line, same as DI
ADDO Synchronous communication ADC output data line
ANA+5 The +5 volt power supply VCC is filtered to produce ANA+5. ANA+5
powers the analog circuitry.
AUDIO Pulse-width-modulated signal representing audio TONE frequency used to
control speaker driver and generated by U4.
BATT Signal used to monitor battery voltage, equals to VBATT in magnitude.
BTEMP COZ2 bench output voltage proportional to the bench temperature.
BUSY Return signal from the external printer or computer. Indicates that remote
device is not ready to receive data from the Monitor. ls converted to CTSO
signal by U10.
ICAL Signal which initializes ADC self-calibration cycle.
3 CKS CKS is the microprocessor’s high-speed, synchronous serial output clock
signal. :
ICONVST Signal which initializes ADC conversion cycle.
CO2 Voltage generated by the gain-offset stage U15A indicating CO2
concentration.
7DACS Signal used to select DAC chip U9.
00-07 Do through D7 are the microprocessor's data lines. The data lines are
routed to RAM, PROM and peripheral devices.
DI Synchronous communication input data line, same as ADDI
DO Synchronous communication output data line
DIR, /DCS Signals used to control bi-directional display communication buffer U5.
EECLK COZ2 bench internal EEPROM clock signal.
/EECS Signal to select CO2 bench internal EEPROM chip.
FAST Log. 0 indicates fast battery charging mode.
Capnocheck
Plus
Service
Manual
3-9