Port C Pin Connections; Table 3-3. Port C Signal Assignments - National Instruments DAQCard-1200 User Manual

Note Table 3-3 shows both the port C signal assignments and the terminology
correlation between different documentation sources. The 82C55A terminology
refers to the different 82C55A configurations as modes, whereas NI-DAQ and
LabVIEW documentation refers to them as handshaking and no handshaking.
These signal assignments are the same for all four 82C55A PPIs.
Configuration Terminology
82C55A/
DAQCard-1200 NI-DAQ/
User Manual LabVIEW
Mode 0 No
(Basic I/O) Handshaking
Mode 1 Handshaking
(Strobed Input)
Mode 1 Handshaking
(Strobed Output)
Mode 2 Handshaking
(Bidirectional Bus)
*Indicates that the signal is active low.
Subscripts A and B denote port A or port B handshaking signals.
© National Instruments Corporation

Port C Pin Connections

The signals assigned to port C depend on how the 82C55A is configured.
In mode 0 or no handshaking configuration, port C is configured as
two 4-bit I/O ports. In modes 1 and 2, or handshaking configuration, port C
is used for status and handshaking signals with zero, two, or three lines
available for general-purpose I/O. Table 3-3 summarizes the port C signal
assignments for each configuration.

Table 3-3. Port C Signal Assignments

PC7 PC6
I/O I/O
I/O I/O
OBF * ACK *
A A
OBF * ACK *
A A
Signal Assignments
PC5 PC4 PC3
I/O I/O I/O
IBF STB * INTR
A A
I/O I/O INTR
IBF STB * INTR
A A
3-17
Chapter 3 Signal Connections
PC2 PC1
I/O I/O
STB * IBFB INTR
A B B
ACK * OBF * INTR
A B B
I/O I/O
A
DAQCard-1200 User Manual
PC0
I/O
B
B
I/O