Appendix C
Changing Hardware Configuration Settings
© National Instruments Corp.
C- 5
AT-GPIB/NI-488M/AT&T UNIX
To change the base I/O address, remove the plastic cover on U25, press
each switch to the desired position, check each switch to make sure it is
pressed down all the way, and place the plastic cover back on again.
Interrupt Selection
The AT-GPIB interface board can use one of 11 interrupt lines on the
PC AT I/O channel. The interrupt line is selected by placing a jumper
across the double rows of pins located above the I/O slot edge connector
on the AT-GPIB (refer to Figure C-1). To select an interrupt line, place
the jumper in the appropriate position. The interrupt lines that the
AT-GPIB hardware can use are IRQ3, 4, 5, 6, 7, 9, 10, 11, 12, 14, and 15.
If you install more than one AT-GPIB interface board in your computer,
each board must be configured to use a unique interrupt request line. The
default AT-GPIB interrupt request levels for the NI-488M for AT&T
UNIX software are shown in Table C-3.
Table C-3. Default AT-GPIB Interrupt Request Lines
Board
Default IRQ Line
First AT-GPIB (gpib0)
11
Second AT-GPIB (gpib1)
10
Note:
Do not use interrupt line 6 or interrupt line 14. Interrupt line 6 is
used by the diskette drive Controller and interrupt line 14 is used
by the hard disk drive Controller on most PC ATs.
Once you have selected an interrupt line, place the jumper on the
appropriate pins to enable the interrupt line. For interrupt lines 3 through
7, or 9, use jumper set W3 (refer to Figure C-1). For lines 10 through 15,
use jumper set W2 (refer to Figure C-1). Figure C-3 shows the default
setting IRQ11, a possible setting of IRQ10, and a jumper set to interrupt
line 5.
