User`s manual

MAIN CONNECTOR DIGITAL I/O REGISTER
BADR3 + 1
READ
DI0, EXT TRIG, EXT PACER, EXT GATEDI1DI2, CTR0 GATEDI30000
01234567
The signals present at the inputs are read as one byte, the most significant 4 bits of which are always
zero. Digital Inputs 2 and 0 have multiple functions. Digital Input 2 may also be used as the gate to
Counter 1 of the 82C54 which is available on the Main connector, please see BADR3+6 for a more
detailed description. Digital Input 0 may also be used as either a trigger, a pacer, or a gate for the ADC,
please see BADR3+5 for a more details.
WRITE
DO0DO1DO2DO3XXXX
01234567
The upper four bits are ignored. The lower four bits are latched TTL outputs. Once written, the state of
the inputs cannot be read back because a read back would read the separate digital input lines (see
above).
NOTE
The digital lines 0-3, pins 3, 4, 5, 6, 22, 23, 24, & 25 of the analog connector
should not be used as ON/OFF Digital I/O. See below.
The digital inputs have multiple functions as described above. The digital outputs are also used by the
CIO-EXP32, 32 channel analog multiplexor/amplifier. There is a 24-line 82C55 on general purpose
digital I/O, see BADR4. We suggest that the Main connector 4-bit ports be kept free for analog
multiplexing control lines
.
ADC CHANNEL STATUS AND SWITCH SETTINGS REGISTERS
BADR3 + 2
READ ONLY
MA0MA1MA2MA3CLKMUXU/BEOC
01234567
EOC = 1, the A/D converter is busy.
EOC = 0, it is free.
EOC is in both BADR3+2 and BADR3+3 for convenience in software programming.
U/B = 1, the Analog Input Polarity Switch is set to Unipolar.
U/B = 0, the Analog Input Polarity Switch is set to Bipolar
MUX = 1, the Analog Input Mode Switch is set to 16 single-ended.
MUX = 0, the Analog Input Mode Switch is set to 8 differential.
CLK = 1, the Pacer Clock Jumper is set to 10 MHz
CLK = 0, the Pacer Clock Jumper is set to 1 MHz.
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