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Appendix C Register-Level Programming
PC-DIO-24/PnP User Manual C-16
©
National Instruments Corporation
Figure C-3. 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 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_ADDRESS + PORTAoffset;
portb = BASE_ADDRESS + PORTBoffset;
portc = BASE_ADDRESS + PORTCoffset;
cnfg = BASE_ADDRESS + CNFGoffset;
/* EXAMPLE 1–port A output */
outp(cnfg,0xA0); /* Port A is an output in mode 1.*/
while (!(inp(portc) & 0x80)); /* Wait until OBFA* is set,
indicating that the data last
written to port A has been
read.*/
outp(porta,0x12); /* Write data to port A. */
PC7
PC6
PC5
PC4
PC3
PC2
PC1
PC0
OBFA*
ACKA*
I/O
I/O
INTRA
ACKB*
OBFB*
INTRB
Group A
Group B