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Changing Hardware and Software Configuration Settings
Appendix A
Interrupt Selection
The GPIB-PCII/IIA interface board can use any of the six interrupt lines
available on the PC, or no interrupts at all. The interrupt line is selected using
the jumper sets labeled IRQ2 through IRQ7 (see Figure A-1). The GPIB-
PCII/IIA is set at the factory to use line 7. To select another interrupt line, place
the supplied jumper across the two pins adjacent to the label designating that
interrupt line. Figure A-6 shows the selection of interrupt line 7.
Figure A-6. Default Interrupt Jumper Setting for GPIB-PCII
If you do not want to use interrupts, you must logically disconnect the GPIB-
PCII/IIA from the IRQ lines by selecting NONE for the interrupt line when you
run IBCONF in Step 2 - Configure the Software later in this chapter. The board
can remain in the backplane and no jumpers have to be moved or changed.
Shared Interrupts in GPIB-PCIIA Mode
The GPIB-PCIIA uses a special feature of the PC called shared interrupts. This
feature allows more than one device to share the same interrupt line, if both
devices have the ability to share interrupts. If you use the GPIB-PCII/IIA in
GPIB-PCIIA mode and you want to change the interrupt line, you must set
switches I0, I1, and I2 in switch set U2 to the line setting in addition to setting
the interrupt jumpers.
PCII/IIA and NI-488.2 MS-DOS
A-12
© National Instruments Corp.
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