Appendix C
Register-Level Programming
©
National Instruments Corporation
C-13
PC-DIO-24/PnP User Manual
0
INTRB
Interrupt Request Status for Port B—When INTEB
and IBFB are high, this bit is high, indicating that an
interrupt request is pending for port B.
At the digital I/O connector, port C has the following pin assignments
when in mode 1 input. Notice that the status of STBA* and the status of
STBB* are not included in the port C status word.
Figure C-2.
Port C Pin Assignments, Mode 1 Input
Mode 1 Input Programming Example
The following example shows how to configure PPI A for various
combinations of mode 1 input. This code is strictly an example and is
not intended to be used without modification in a practical situation.
Main() {
#define BASE_ADDRESS
0x180
/* Board located at address 180 */
#define PORTAoffset
0x00
/* Offset for port A */
#define PORTBoffset
0x01
/* Offset for port B */
#define PORTCoffset
0x02
/* Offset for port C */
#define CNFGoffset
0x03
/* Offset for CNFG */
unsigned int porta, portb, portc, cnfg;
char valread;
/* Variable to store data read from a port */
/* Calculate register addresses */
porta = BASE_A PORTAoffset;
portb = BASE_A PORTBoffset;
portc = BASE_A PORTCoffset;
cnfg = BASE_A CNFGoffset;
PC7
PC6
PC5
PC4
PC3
PC2
PC1
PC0
I/O
I/O
IBFA
STBA*
INTRA
STBB*
IBFB
INTRB
Group A
Group B
