Справочник Пользователя для National Instruments PCI-DIO-96

Chapter 3

Signal Connections

 National Instruments Corporation

3-5

PCI-DIO-96 User Manual

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 3-2 
summarizes the port C signal assignments for each configuration. 
Consult Chapter 6, Programming, for register-level programming 
information.

Table 3-2 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, ComponentWorks, LabWindows/CVI, and LabVIEW 
documentation refers to them as handshaking and no handshaking. These 
signal assignments are the same for all four 82C55A PPIs. Refer to Port 
Identification in Chapter 6, Programming, for more information.

83, 85, 87, 89, 
91, 93, 95, 97

CPA<7..0>

Bidirectional data lines for port A of PPI C—CPA7 is the 
MSB, CPA0 the LSB.

84, 86, 88, 90, 
92, 94, 96, 98

DPA<7..0>

Bidirectional data lines for port A of PPI D—DPA7 is the 
MSB, DPA0 the LSB.

Table 3-2.  Port C Signal Assignments  

Mode 0
(Basic I/O)

No 
Handshaking

I/O

I/O

I/O

I/O

I/O

I/O

I/O

I/O

Mode 1
(Strobed Input)

Handshaking 

I/O

I/O

IBFA

STBA*

INTRA

STBB*

IBFBB

INTRB

Table 3-1.  Signal Descriptions for PCI-DIO-96 I/O Connector Pins  (Continued)