Agilent Technologies 4294A Programming Manual page 126

Communication with External Equipment (Using the I/O Ports)
Using the I/O Ports
Basic input/output circuit
Table 9-2 Basic input/output circuit of the 24-bit I/O port
126
Basic
Input port
circuit
I/O pin INPUT1
Basic Output port
circuit
I/O pin OUTPUT1, 2
*1
Port A , B
*1
D (output)
Write strobe signal
SWEEP END signal
Port C status, port D status
*1.Common to all bits
*1 *1
, C (output) ,
*1
Ports C, D (input)
Other
+5V pull-up
Chapter 9