Service manual

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