Hardware Configuration and Installation
Chapter 2
GPIB-PCIIB/MS-DOS
2-6
© National Instruments Corp.
DMA Channel Selection
The DMA channel used by the GPIB-PCIIB is selected by jumpers located
at the lower center of the interface board (see Figure 2-1). The GPIB-PCIIB
is set at the factory to use DMA channel 1. Verify that this DMA channel is
not also used by equipment already installed in your computer. If any
device uses DMA channel 1, change the DMA channel used by either the
GPIB-PCIIB or the other device. The GPIB-PCIIB hardware can use DMA
channels 1, 2, or 3, or no channel at all. Each DMA channel consists of two
signal lines as shown in Table 2-2.
Table 2-2. DMA Channels for the GPIB-PCIIB
Signal Lines
DMA
Channel
DMA
Acknowledge
DMA
Request
1
DACK1
DRQ1
2
DACK2
DRQ2
3
DACK3
DRQ3