National Instruments AT-MIO-16D, User Manual, Page: 183 / 291

Chapter 4 Programming
© National Instruments Corporation 4-91 AT-MIO-16D User Manual
Table 4-10. DIO-24 Interrupt Enable Signals for All Mode Combinations
Port A
Mode 2
Output
Port A
Mode 2
Input
Port B
Mode 1
Output
Port B
Mode 1
Input
Port A
Mode 1
Output
Port A
Mode 1
Input
Port B
Mode 0
Port A
Mode 0
Interrupt
Enable
Bit
No No No No No No Yes Yes N/C
No No No No No Yes Yes No PC6, PC2
No No No No Yes No Yes No PC4, PC2
No No No Yes No No No Yes PC6, PC4
No No No Yes No Yes No No PC6
No No No Yes Yes No No No PC4
No No Yes No No No No Yes PC6, PC4
No No Yes No No Yes No No PC6
No No Yes No Yes No No No PC4
No Yes No No No No Yes No PC2
No Yes No Yes No No No No N/C
No Yes Yes No No No No No N/C
Yes No No No No No Yes No PC2
Yes No No Yes No No No No N/C
Yes No Yes No No No No No N/C
The recommended jumper settings for W14 are as follows:
• PC6 – If Port A is in Mode 1 input.
• PC4 – If Port A is in Mode 1 output.
• PC2 – If Port A is in Mode 2 (Port B is not in Mode 1).
To enable interrupts from the DIO-24 circuitry of the AT-MIO-16D board, select PC2, PC4, or
PC6 as the active low interrupt enable signal. Initially, set the selected bit high to disable
unwanted interrupts.
Program the DIO-24 circuitry for the I/O mode you want. To enable interrupts from the
82C55A, set either the INTEA or the INTEB bit to enable interrupts from Port A or Port B,
respectively. In Mode 2, set either INTE1 or INTE2 for interrupts on input or output transfers.
After interrupts have been enabled from the 82C55A, clear the selected interrupt enable bit to
enable interrupts from the DIO-24 circuitry.
An external signal can be used to interrupt the AT-MIO-16D when Port A or Port B is in Mode
0. Select PC2, PC4, or PC6 as the interrupt enable bit and clear the selected bit to enable
interrupts. Connect the external signal that should trigger an interrupt to either PC3 or PC0.
When the external signal becomes logic high, an interrupt request occurs. To disable the external
signal interrupt, set the selected interrupt enable bit to logic high.