User manual

Appendix D Register-Level Programming

National Instruments Corporation D-19 PC-DIO-96/PnP User Manual

At the digital I/O connector, port C has the following pin assignments

when in mode 1 output. Notice that the status of ACKA* and the status

of ACKB* are not included when port C is read.

Figure D-4. Port C Pin Assignments, Mode 1 Output

Mode 1 Output Programming Example

The following example shows how to configure PPI A for various

combinations of mode 1 output. 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 APORTAoffset 0x00 /* Offset for PPI A, port A */

#define APORTBoffset 0x01 /* Offset for PPI A, port B */

#define APORTCoffset 0x02 /* Offset for PPI A, port C */

#define ACNFGoffset 0x03 /* Offset for PPI A, CNFG */

unsigned int porta, portb, portc, cnfg;

char valread; /* Variable to store data read from a port */

/* Calculate register addresses */

porta = BASE_ADDRESS + APORTAoffset;

portb = BASE_ADDRESS + APORTBoffset;

portc = BASE_ADDRESS + APORTCoffset;

cnfg = BASE_ADDRESS + ACNFGoffset;

PC7

PC6

PC5

PC4

PC3

PC2

PC1

PC0

OBFA*

ACKA*

I/O

INTRA

ACKB*

OBFB*

INTRB

Group A

Group B