Configuration and Installation Chapter 2
PC-DIO-24 User Manual 2-4 © National Instruments Corporation
Interrupt Selection
There are two sets of jumpers for interrupt selection on the PC-DIO-24 board. W1 is used for
selecting the interrupt enable line. W2 is for selecting the interrupt level. The location of these
jumpers is shown in Figure 2-1.
Interrupt Enable Settings
To enable interrupt requests from the PC-DIO-24, you must set jumper W1 to select PC2, PC4,
or PC6 as the active low interrupt enable line. When the interrupt enable line is logic low,
interrupts are enabled from the PC-DIO-24 board. Refer to Chapter 4, Register-Level
Programming, for the suggested interrupt enable line setting for each digital I/O mode of
operation. If W1 is set to N/C, all interrupt requests from the PC-DIO-24 are disabled.
Figure 2-3 shows the possible jumper settings for W1. The board is shipped with this jumper set
to PC4; therefore, interrupt requests from the board are enabled and controlled by PC4.
W1
INT
PC6
PC4
PC2
N/C
(Default Factory Setting)
W1
INT
PC6
PC4
PC2
N/C
W1
INT
PC6
PC4
PC2
N/C
W1
INT
PC6
PC4
PC2
N/C
Figure 2-3. Jumper Settings–PC6, PC4, PC2, and N/C
Interrupt Level Settings
The PC-DIO-24 board can connect to any one of the six interrupt lines of the PC I/O Channel:
IRQ3, IRQ4, IRQ5, IRQ6, IRQ7, or IRQ9. You select the interrupt line by setting a jumper on
W2. To use the interrupt capability of the board, you must select an interrupt line and place the
jumper in the appropriate position. The default interrupt line is IRQ5. To change to another line,
remove the jumper from IRQ5 and place it on the pins for another request line. Figure 2-4 shows
the default factory setting for IRQ5.
345679
IRQ
W2
Figure 2-4. Interrupt Jumper Setting for IRQ5 (Factory Setting)