Chapter 2
Hardware Configuration and Installation
© National Instruments Corporation
2-3
VXI-AT2023/NI-VXI ISC 386/ix Getting Started
Switch and Jumper Settings
You can configure three options on the AT-MXI board:
•
Base I/O address
•
Interrupt levels
•
DMA channels
Table 2-1 shows the factory settings and optional configurations for the switches and jumpers on
the AT-MXI.
Table 2-1. AT-MXI Factory Default Settings and Optional Configurations
AT-MXI
Default
Optional
Base I/O Address (hex)
340
100 to 3E0, increments of 20 hex
Master DMA Channel
6
0, 1, 2, 3, 5, 6, 7, and Not Used
Slave DMA Channel
3
0, 1, 2, 3, 5, 6, 7, and Not Used
Board Interrupt Level
12
3, 4, 5, 6, 7, 9, 10, 11, 12, 14, and 15
MXIbus Interrupt Level
10
3, 4, 5, 6, 7, 9, 10, 11, 12, 14, 15,
and Not Used
The factory-configured settings of the base I/O address, the interrupt levels, and the Direct Memory
Access (DMA) channels are suitable for most computer systems. The following sections describe
under what conditions you would be required to change the configuration switches and/or jumpers
on the AT-MXI and how to make these changes.
Base I/O Address Selection
The base I/O address of the AT-MXI is the starting address of the AT-MXI configuration registers
in PC AT I/O space. The base I/O address is determined by the position of the five switches at
location U31, as shown in Figure 2-1. The switches are set at the factory for a base I/O address of
340 hex. Because the AT-MXI requires 32 bytes of consecutive I/O space for its internal registers,
the factory configuration uses the I/O address space in the range of 340 to 35F hex.
Note:
Check to determine that this space is not already used by other I/O interfaces installed in
your PC AT computer. If any equipment in your computer uses this I/O address space,
you must change either the base I/O address of the AT-MXI or the I/O address space
requirements of the other device. All PC AT devices must have a unique partition of the
system's I/O address space. If you change the base I/O address of the AT-MXI, you
must make a corresponding change to the AT-MXI configuration software as described
in the Configuring the NI-VXI Software section of Chapter 3 of this manual.