
Chapter 4
Software Reference
© National Instruments Corp.
4-29
GPIB-410 User Manual
•
(DMA) 3
•
(PIO) NONE
Any one of the valid DMA channels can be selected if the channel is
not already in use by another device. The value selected must match
the input DMA channel jumper setting (
C
#
) on the GPIB-410 interface
board. It is permissible to set the input and output DMA channels to the
same value provided capturing and generating are never used at the
same time.
Warning:
Attempting to perform a capture operation with a DMA
channel already in use by another device may crash your
system or have other unpredictable effects.
If there is no unused DMA channel available on your computer, you can
select programmed I/O (PIO) operation by setting this field to
NONE
.
However, because PIO greatly reduces the performance of most capture
operations, it is recommended that this option be used only when
absolutely necessary.
Output DMA Channel
Use this field to specify the method by which user-defined pattern
buffers are loaded from system memory into the drive latches of the
GPIB-410. There are four options.
•
(DMA) 1
•
(DMA) 2
•
(DMA) 3
•
(PIO) NONE
(default)
Any one of the valid DMA channels can be selected if the channel is
not already in use by another device. The value selected must match
the output DMA channel jumper setting (
S
#
) on the GPIB-410 interface
board. It is permissible to set the input and output DMA channels to the
same value if capturing and generating are never used at the same time.