User manual

Appendix D Register-Level Programming

National Instruments Corporation D-13 PC-DIO-96/PnP User Manual

Mode 0 Programming Example

The following example shows how to configure PPI A for various

combinations of mode 0 input and 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;

9 10010001 Input Output Output Input

10 10010010 Input Output Input Output

11 10010011 Input Output Input Input

12 10011000 Input Input Output Output

13 10011001 Input Input Output Input

14 10011010 Input Input Input Output

15 10011011 Input Input Input Input

Upper nibble of port C

Lower nibble of port C

Table D-3. Mode 0 I/O Configurations (Continued)

Control Word Group A Group B

Number Bit

76543210

Port A Port C

Port B Port C