Chapter 7
ibconf—Interface Bus Configuration Utility
© National Instruments Corp.
7-15
NI-488.2M SRM for OS/2
Interrupt Jumper Setting (Board Characteristic Only)
This field specifies the interrupt line used by the GPIB board. It must be set to
the same value as the interrupt level setting for the GPIB board. Setting the
interrupt level is explained in the getting-started manual that you received with
your GPIB board.
Note: On Micro Channel systems, you can change the interrupt level only by
booting the reference diskette. However, you can enable or disable the
use of interrupts with the
ibconf
utility.
DMA Transfer Mode (Board Characteristic Only)
This field specifies the DMA transfer mode of the GPIB board. Nearly all PC-
compatible computers can use Demand Mode DMA, which is the fastest DMA
mode. Certain newer machines, however, cannot use Demand Mode DMA;
these machines should use Single Cycle DMA. The default option for this
characteristic is
Demand Mode DMA
.
Note:
This characteristic is not applicable to Micro Channel systems.
Serial Poll Timeout (Device Characteristic Only)
This timeout value controls the length of time the driver waits for a serial poll
response from a device. The IEEE 488 standard does not specify the length of
time a Controller should wait for the response byte. The default value of 1 s
should work for most devices. If you have problems with serial polls, try using a
longer timeout value.
Enable Repeat Addressing (Device Characteristic Only)
Normally, devices are not addressed each time a read or write operation is
performed. If
no
is selected, read or write operations do not readdress the
selected device if the same operation was just performed with that device. This
saves some time when you have several GPIB operations to perform after repeat
addressing. But it might be a problem for some older IEEE 488 devices that
require their GPIB address to be sent with each I/O operation. Select
yes
to
enable repeat addressing in such a situation. The default option for this
characteristic is
no
.