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Chapter
6 NI-VXI
Configuration
Utility
6-14
ni.com
You can select the
Yes
or
No
options to manually determine whether the
PCI-MXI-2 should be the MXIbus System Controller. You must still be
certain to cable the MXIbus system appropriately when you make either of
these selections.
Note
Make sure the MXI-2 cable is connected to the PCI-MXI-2 when you power on or
reboot the computer. This is required for the PCI-MXI-2 to automatically detect whether it
will be the MXIbus System Controller.
MXI Bus Timeout
The MXIbus Bus Timeout (BTO) is a watchdog timer for transfers on the
MXIbus. The MXIbus BTO operates only when the PCI-MXI-2 is acting
as the MXIbus System Controller.
After the specified amount of time has elapsed, the BTO circuitry
terminates a MXIbus cycle if no slave has responded. The BTO is also
disabled when the current MXIbus cycle maps to the VXI/VMEbus through
a VXI/VME-MXI-2.
The default timeout value is 1 ms. If the
Enable MXI-2 Auto Retry
checkbox option is enabled, you should use a
MXI Bus Timeout
of 1 ms
or greater.
MXI CLK10
The PCI-MXI-2 is capable of either receiving or driving the MXIbus
CLK10 signal.
You can use the
Drive
or
Receive
options of the
MXI CLK10
feature to
control the direction of the MXIbus CLK10 signal. By default all MXI-2
boards receive MXI CLK10 (the
Receive
option is active); therefore, you
must choose one board on your MXI-2 bus to drive CLK10 by changing the
value of the control to
Drive
. For most configurations, it is recommended
to choose the System Controller as the CLK10 source for simplicity. The
only exception you may want to make is if you want your triggers
synchronous to the VXI 10 MHz clock.
Caution
Do
not
configure more than one MXIbus device to drive MXIbus CLK10. Having
a second device driving MXIbus CLK10 could damage the device.