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Chapter 4 Signal Connections
National Instruments Corporation 4-53 AT-MIO/AI E Series User Manual
Timing Specifications for Digital I/O Ports A, B, and C
♦ AT-MIO-16DE-10 only
In addition to its function as a digital I/O port, digital port C,
PC<0..7>, can also be used for handshaking when performing data
transfers with ports A and B. The signals assigned to port C depend
on the mode in which it is programmed. In mode 0, port C is
considered two 4-bit I/O ports. In modes 1 and 2, port C is used for
status and handshaking signals with two or three additional I/O
bits. Table 4-5 summarizes the signal assignments of port C for
each programmable mode.
Table 4-5. Port C Signal Assignments
Programming
Mode
Group A Group B
PC7 PC6 PC5 PC4 PC3 PC2 PC1 PC0
Mode 0
I/O
I/O I/O I/O I/O I/O I/O I/O
Mode 1 Input I/O
I/O IBF
A
STB
A
* INTR
A
STB
B
* IBFB
B
INTR
B
Mode 1 Output OBF
A
*
ACK
A
* I/O I/O INTR
A
ACK
B
* OBF
B
* INTR
B
Mode 2 OBF
A
*
ACK
A
* IBF
A
STB
A
* INTR
A
I/O I/O I/O
* Indicates that the signal is active low.