Chapter 6 NI-VXI Configuration Utility
© National Instruments Corporation 6-25 PCI-MXI-2 for Linux
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Figure 6-9. Advanced VXI Settings
VXI/VME Auto Retry
The VXI/VME-MXI-2 has an automatic retry feature for cycles that map
from the VXI/VMEbus to the MXIbus. By default this option is disabled.
Normally, when a cycle maps from the VXI/VMEbus to the MXIbus, any
retry response received on the MXIbus is passed to the VXI/VMEbus.
Ifyou enable the Auto Retry feature, the VXI/VME-MXI-2 automatically
retries any MXI cycle that receives aretry response instead of passing a
retry response back to the VXI/VMEbus. The VXI/VME-MXI-2
automatically continues to retry the MXI cycle until it receives either a
DTACK or BERR response, which it then passes to the VXI/VMEbus.
Notice that the VXI/VME-MXI-2 has a limit on the number of automatic
retries it will perform on any one cycle. If the limit is exceeded and the
VXI/VME-MXI-2 receives another retry, it will pass a retry back to the
VXI/VMEbus even though Auto Retry is enabled.
Transfer Limit
You can use this feature to control how many data transfers the
VXI/VME-MXI-2 will perform on the VXI/VMEbus before releasing it to
another master device that is requesting use of the bus.
The available options you can choose from are 16, 64, and 256 transfers.
Ifyou do not want the VXI/VME-MXI-2 to hold the VXI/VMEbus long