Chapter 2
Hardware Configuration and Installation
© National Instruments Corporation
2-3
VME-AT2000/NI-VXI MS-DOS 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.