Справочник Пользователя для National Instruments PC-DIO-24

/* EXAMPLE 1*/
outp(cnfg,0x80);

/* Ports A, B, and C are outputs. */

outp(porta,0x12);

/* Write data to port A. */

outp(portb,0x34);

/* Write data to port B. */

outp(portc,0x56);

/* Write data to port C. */

/* EXAMPLE 2*/
outp(cnfg,0x90);

/* Port A is input; ports B and C are 

outputs. */

outp(portb,0x22);

/* Write data to port B. */

outp(portc,0x55);

/* Write data to port C. */

valread = inp(porta);

/* Read data from port A. */

/* EXAMPLE 3 */
outp(cnfg,0x82);

/* Ports A and C are outputs; port B 

is an input. */

/* EXAMPLE 4 */
outp(cnfg,0x89);

/* Ports A and B are outputs; port C 

is an input. */

}

In mode 1, the digital I/O bits are divided into two groups—group A and group B.  Each of these
groups contains one 8-bit port and one 4-bit control/data port.  The 8-bit port can be either an
input or an output, and the 4-bit port is used for control and status information for the 8-bit port.
The transfer of data is synchronized by handshaking signals in the 4-bit port.

The control word written to the CNFG Register to configure port A for input in mode 1 is shown
as follows.  Bits PC6 and PC7 of port C can be used as extra input or output lines.

1

0

1

1

1/0

X

X

X

7

6

5

4

3

2

1

0

 

 1 = input

 0 = output

Port C bits PC6 and PC7

The control word written to the CNFG Register to configure port B for input in mode 1 is shown
as follows.  Notice that port B does not have extra input or output lines from port C.

1 

X

X

X

X

1

1

X

7

6

5

4

3

2

1

0