Hardware Configuration and Installation
Chapter 2
VXI-AT2023/NI-VXI ISC 386/ix Getting Started
2-4
© National Instruments Corporation
Each switch in U31 (1 through 5) corresponds to one of the PC AT address lines (A5 through A9).
The first switch (1) corresponds to address line A5, the next switch (2) corresponds to address line
A6, and so on. The five least significant bits of the address (A4 through A0) are used by the
AT-MXI to select the appropriate AT-MXI register and cannot be changed; therefore, bits A4
through A0 are always zeros when determining the base I/O address.
To change the base I/O address of the AT-MXI, press the side marked OFF to select a binary value
of 1 for the corresponding address bit. Press the ON side of the switch to select a binary value of 0
for the corresponding address bit. Refer to Table 2-2.
Figure 2-2 shows two possible switch settings.
OFF
5
4
3
2
1
U31
Binary Hex
0
0
0
0
0
ON=0
ON=0
ON=0
OFF=1
ON=0
a. Switch Set to Base I/O Address hex 100
0
0
1
OFF
5
4
3
2
1
U31
Binary Hex
0
0
0
0
0
ON=0
OFF=1
ON=0
OFF=1
OFF=1
b. Switch Set to Default Setting
(Base I/O Address hex 340)
0
4
3
Figure 2-2. Base I/O Address Switch Settings
