Agilent Technologies 4294A Programming Manual page 127

Communication with External Equipment (Using the I/O Ports)
Preset states at power-on
The 24-bit I/O port is set at power-on as follows (not affected at reset).
Logic Negative logic
Write strobe signal HIGH
SWEEP END signal HIGH
Port A Negative 0 Æ HIGH
Port B Negative 0 Æ HIGH
Port C Input
Port D Input
OUTPUT1 HIGH, HIGH at the fall of the INPUT1 input
OUTPUT2 HIGH, HIGH at the fall of the INPUT1 input
PASS/FAIL signal (Negative) Æ HIGH
Commands to control the 24-bit I/O port
To output data to each output port (A to H), use the following commands.
GPIB command Instrument BASIC command
"OUTAIO" on page 369 "WRITEIO 16,0;"
"OUTBIO" on page 369 "WRITEIO 16,1;"
"OUTCIO" on page 370 "WRITEIO 16,2;"
"OUTDIO" on page 370 "WRITEIO 16,3;"
"OUTEIO" on page 371 "WRITEIO 16,4;"
"OUTFIO" on page 371 "WRITEIO 16,5;"
"OUTGIO" on page 372 "WRITEIO 16,6;"
"OUTHIO" on page 372 "WRITEIO 16,7;"
To use ports C, D, E, F, G and H as output ports, use the following commands to set ports C
and D as output ports in advance.
• "COUT" on page 283
• "DOUT" on page 307
Chapter 9
Using the I/O Ports
Description
Outputs 8-bit width data to port A.
Outputs 8-bit width data to port B.
Outputs 4-bit width data to port C.
Outputs 4-bit width data to port D.
Outputs 8-bit width data to port E.
Outputs 16-bit width data to port F.
Outputs 20-bit width data to port G.
Outputs 24-bit width data to port H.
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