Chapter 6 NI-VXI Configuration Utility
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National Instruments Corporation 6-27 VXI/VME-PCI802 2 for Sola ris

VXI/VME Fair Requester

The VXI/VME-MXI-2 is always a Release On Re qu est re que st e r.
However, you can configure whether the VXI/VME-MXI-2 acts as
either a fair or unfair requester on the VXI/VMEbus. By default the
Operate as Fair Requester checkbox is enabled, signifying a fair
requester. For more information on the different types of requesters,
refer to the VMEbus specification.

Arbiter Timeout

An arbitration timeout feature is available on the VXI/VME-MXI-2
when it is acting as the VMEbus arbiter. This feature applies only to a
VXI Slot 0 (VMEbus System Controller) VXI/VME-MXI-2. By default
this option is enabled.
The timer begins when the arbiter circuit on the VXI/VME-MXI-2
drives one of the BGOUT lines on the backplane. If no device takes over
the bus within the timeout limit, the BGOUT is removed and the bus is
either idle or granted to another requester.
MXI Bus Options
Use the options in this group to control features of the MXIbus interface
on the VXI/VME-MXI-2 module.
MXI Bus System Controller
You can use the System Controller control to determine whether the
VXI/VME-MXI-2 acts as the MXI Bus System Controller. When the
Auto setting (the default setting) is active, the VXI/VME-MXI-2
automatically can sense from the MXIbus cable whether it should be the
controller.
You can select either Yes or No to manually determine if the
VXI/VME-MXI-2 should be the MXI Bus System Controller. You must
still be certain to cable the MXIbus system appropriately when you
make either of these selections.
MXI Bus Timeout Value
The MXI Bus Timeout (BTO) is a watchdog timer for transfers on
the M XIbus. The MXIbus BTO unit operates only when the
VXI/VME-MXI-2 is acting as the MXI Bus System Controller. The
functionality of this control is similar to that of the VXI Bus Timeout