Configuration and Installation Chapter 3
VXI-MXI User Manual 3-8 © National Instruments Corporation

a. Level 3 Requester (default)

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VMEbus Request Level
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b. Level 2 Requester

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VMEbus Request Level
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c. Level 1 Requester

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d. Level 0 Requester

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Figure 3-6. VMEbus Requester Jumper Settings

VMEbus Timeout Value

When a VXI-MXI is installed in a VXIbus mainframe, the VME Bus Timeout Unit (BTO)

circuitry for the VXIbus mainframe must be on the VXI-MXI. If there are multiple VXI-MXI

interfaces in a mainframe, the BTO must be enabled on one of them and they must be in adjacent

slots. In the case of multiple VXI-MXIs, it is recommended that the BTO be enabled on the

VXI-MXI that is installed in Slot 0. The BTO monitors the current bus cycle and asserts the bus

error (BERR) signal if a data transfer acknowledge (DTACK) or BERR is not received from the

selected slave within the given amount of time after data strobe (DS1 or DS0) becomes active.

Whenever a MXIbus transfer into or out of the VXI-MXI occurs, the VMEbus timeout on the

VXI-MXI is disabled and the MXIbus System Controller BTO monitors the transfer. This