Appendix B
Register-Level Programming
DAQCard-DIO-24 User Manual
B-20
©
National Instruments Corporation
4
INTE2
Interrupt Enable Bit for Input—If this bit
is set, interrupts are enabled from the
82C55A for IBFA. Controlled by bit
set/reset of PC4.
3
INTRA
Interrupt Request Status—If INTE2 is
high and IBFA is high, this bit is high,
indicating that an interrupt request is
asserted for input transfers. If INTE1 is
high and OBFA* is high, this bit is high,
indicating that an interrupt request is
asserted for output transfers.
2–0
I/O or
Input/Output—Extra I/O status lines
port B
available if port B is not configured for
handshaking mode 1.
Figure B-4 shows the pin assignments for port C when in mode 2 at the
digital I/O connector.
Figure B-4.
Port C Pin Assignments in Mode 2
PC7
PC6
PC5
PC4
PC3
PC2
PC1
PC0
OBFA*
ACKA*
IBFA
STBA*
INTRA
I/O
or
Hand-
shaking
Group A
Group B