National Instruments 6023E, 6024E, 6025E Port C Pin Assignments

Chapter4 SignalConnections
©NationalInstruments Corporation 4-23 6023E/6024E/6025EUser Manual
TTL signals andd rivingexternal devices such as the LED shown in
Figure 4-11.
Port C Pin Assignments
♦6025 only
The signals assigned to port C depend on howthe 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 usedfor status and handshaking signal swith any leftover lines available
forgeneral-purpose I/O. Table 4-4 summarizes the port C signal
assignments foreach configuration. You can also use ports A and B in
differentmodes; the ta ble does not showevery possible combination.
Note Table4-4 shows both the port C signal assignments and the terminology
correlation betweendifferent documentation sources. The 82C55A terminology refers
to the different82C55A con figurationsas modes, wh ereas NI-DAQ,ComponentWorks,
LabWindows/CVI,and LabVIEW documentation refers to them as handshaking and no
handshaking.
Table4-4. PortC Signal Assignments
ConfigurationTerminology SignalAssignments
6023E/
6024E/6025E
UserManual
National
Instruments
Software PC7 PC6 PC5 PC4 PC3 PC2 PC1 PC0
Mode0
(BasicI/O)
No
Handshaking
I/O I/O I/O I/O I/O I/O I/O I/O
Mode1
(StrobedInput)
Handshaking I/O I/O IBFASTBA*INTRASTBB*IBFBBINTRB
Mode1
(StrobedOutput)
Handshaking OBFA*ACKA*I/O I/O INTRAACKB*OBFB*INTRB
Mode2
(Bidirectional
Bus)
Handshaking OBFA*ACKA*IBFASTBA*INTRAI/O I/O I/O
*Indicates that the signal is active low.
SubscriptsA and B denote port Aorport B handshaking signals.