National Instruments PC-DIO-96 Manual Do Utilizador

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.

PC7

PC6

PC5

PC4

PC3

PC2

PC1

PC0

I/O

I/O

IBFA

STBA*

INTRA

STBB*

IBFB

INTRB

Group A

Group B

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 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;

/* EXAMPLE 1–port A input */

outp(cnfg,0xB0);

/* Port A is an input in mode 1. */

while (!(inp(portc) & 0x20));

/* Wait until IBFA is set, indicating that

data has been loaded in port A. */

valread = inp(porta);

/* Read the data from port A. */

/* EXAMPLE 2–Port B input */

outp(cnfg,0x86);

/* Port B is an input in mode 1. */

while (!(inp(portc) & 0x02));

/* Wait until IBFB is set, indicating that

data has been loaded in port B. */

valread = inp(portb);
}