Bus Configuration; Table 3-2. Bus Configuration Characteristics - National Instruments VXI-AT2023 Getting Started

Chapter 3

Bus Configuration

Table 3-2 describes the characteristics of the options available under the Bus Configuration
menu.
Characteristic
MXIbus System
Controller
MXIbus Fair Request
MXIbus Interrupt Level
© National Instruments Corporation

Table 3-2. Bus Configuration Characteristics

Description
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
MXIbus 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 you add more
MXIbus devices 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
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 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)
3-9
NI-VXI Software Installation and Configuration
VXI-AT2023/NI-VXI ISC 386/ix Getting Started
Default Value
1
0
0xff