Справочник Пользователя для National Instruments PC-DIO-96
Register-Level Programming
Chapter 4
PC-DIO-96 User Manual
4-16
© National Instruments Corporation
Bit
Name
Description (continued)
2
INTEB
Interrupt Enable Bit for Port B—Setting this bit enables interrupts
from port B of the 82C55A. This bit is controlled by
setting/resetting PC2.
from port B of the 82C55A. This bit is controlled by
setting/resetting PC2.
1
OBFB*
Output Buffer for Port B—A low setting indicates that the CPU
has written data to port B.
has written data to port B.
0
INTRB
Interrupt Request Status for Port B—When INTEB and OBFB* are
high, this bit is high, indicating that an interrupt request is pending
for port B.
high, this bit is high, indicating that an interrupt request is pending
for port B.
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.
Notice that the status of ACKA* and the status of ACKB* are not included when port C is read.
PC7
PC6
PC5
PC4
PC3
PC2
PC1
PC0
OBFA*
ACKA*
I/O
I/O
INTRA
ACKB*
OBFB*
INTRB
Group A
Group B
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.
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;
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;
portb = BASE_ADDRESS + APORTBoffset;
portc = BASE_ADDRESS + APORTCoffset;
cnfg = BASE_ADDRESS + ACNFGoffset;
/* EXAMPLE 1–port A output */