Hardware Configuration and Installation
Chapter 2
AT-GPIB for SCO UNIX
2-16
© N ational Instruments Corp.
If you do not want to use DMA for GPIB transfers (the AT-GPIB board
alternatively can use programmed I/O GPIB transfers), you can perform one
of the following steps:
•
Physically disconnect the AT-GPIB board from the DMA channel lines
of the PC AT bus by removing the two jumpers. The jumpers can be
stored on the board in the positions shown in Figure 2-5. Removing the
jumpers disables the ability of the AT-GPIB board to assert a DRQ line
on the PC AT I/O channel. Make sure that you make a corresponding
change to the software DMA channel setting during the software
installation discussed in Chapter 3, Software Installation and
Configuration .
DRQ5
DRQ7
DACK7
DRQ6
DACK6
DACK5
IRQ
15
14
12
11
10
Figure 2-5. DMA Jumper Setting for No DMA Channel
•
Logically disconnect the AT-GPIB board from the DMA lines by
selecting NONE for the DMA channel of the AT-GPIB board when
you run
IBCONF
(refer to Chapter 3, Software Installation and
Configuration , for information on running
IBCONF
). By using this
programmable method, the board can remain installed in the backplane
and no jumpers have to be moved or changed.