Vmebus Request Level Selection; Figure 2-10. Logical Address Selection - National Instruments VXI-AT2022 Getting Started

Chapter 2
VXI-MXI by changing the setting of the 8-bit DIP switch labeled LOGICAL ADDRESS SWITCH
on the front panel. The ON position on the DIP switch corresponds to a logic value of 0, and the
OFF position corresponds to a logic value of 1. Verify that the VXI-MXI does not have the
same logical address as any other statically configured VXIbus device in your system.
Remember that logical addresses hex 0 and FF are not allowed for the VXI-MXI.
Figure 2-10 shows switch settings for logical address hex 1 and C0.

VMEbus Request Level Selection

The VXI-MXI uses one of the four VMEbus request levels to request use of the VME Data
Transfer Bus (DTB). The VXI-MXI requests use of the DTB whenever an external MXIbus
device, such as a PC AT computer with an AT-MXI interface, attempts a transfer that maps into
the VXIbus mainframe.
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LOGICAL ADDRESS
SWITCH
OFF ON
1
Shown at
2
Default setting
3
of Logical Address 1
4
5
6
7
8
a. Switch Setting to Default Setting Logical Address
LOGICAL ADDRESS
SWITCH
OFF ON
1
Shown at
2
Default setting
3
of Logical Address 1
4
5
6
7
8
b. Switch Set to Logical Address hex C0

Figure 2-10. Logical Address Selection

Hardware Configuration and Installation
Push this side down for logic 0
Push this side down for logic 1
Push this side down for logic 0
Push this side down for logic 1
2-19 VXI-AT2022/NI-VXI SCO UNIX Getting Started