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NI-VXI Software Installation and Configuration
Chapter 3
VXI-AT2022/NI-VXI SCO UNIX Getting Started
3-10
© National Instruments Corporation
Bus Configuration
Table 3-2 describes the characteristics of the options available under the Bus Configuration menu.
Table 3-2. Bus Configuration Characteristics
Characteristic
Description
Default Value
MXIbus System
Controller
A MXIbus link must have a single device that
is responsible for MXIbus interrupt and bus
arbitration as well as bus timeouts. This device
is referred to as the MXIbus System Controller
and is always the first device in the MXIbus
daisy-chain. The AT-MXI is always
designated as the MXIbus System Controller
when used in this kit and should not be
changed.
0 = Not MXIbus System Controller
1 = MXIbus System Controller
1
MXIbus Fair Request
MXIbus fair requesters give all MXIbus
devices equal opportunity to become bus
masters and transfer data, regardless of their
position within the MXIbus daisy-chain.
MXIbus devices that are not fair requesters
have a fixed priority scheme characterized by
their relative position within the MXIbus daisy-
chain. Devices closest to the MXIbus System
Controller have the highest priority. The
default configuration programs the AT-MXI to
be an unfair requester and should be changed
only if additional MXIbus devices are added to
the system. Refer to the user manual included
with your additional MXIbus devices for more
information.
0 = Not a MXIbus Fair Requester
1 = MXIbus Fair Requester
0
MXIbus Interrupt Level
Indicates the interrupt level used by the MXI
IRQ to interrupt the processor. This value must
correspond to jumper settings on the AT-MXI
board; however, you can select the NONE
option with any jumper settings. If you select
the NONE option, the same interrupt level as
used for AT-MXI board interrupts is used for
this interrupt.
Range = 3, 4, 5, 6, 7, 9, 10, 11, 12, 14, 15,
or 0xff (NONE)
0xff