Appendix B
Common Questions
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National Instruments Corporation
B-7
PCI-Based MXI-2 Interface for Windows
What do the LEDs on the front of the VXI-MXI-2 or VME-MXI-2
mean?
The
SYSFAIL
LED shows the state of the VXIbus/VMEbus SYSFAIL
line. This line is asserted whenever any device in the chassis has not yet
passed the self-test, if it has failed the self-test, or if it has detected a failure
after originally passing the self-test. The
MXI
LED indicates that the
VXI-MXI-2 or VME-MXI-2 is acting as a slave to another device on
the MXIbus, such as when the PCI-MXI-2, PCI-MXI-2 Universal, or
PXI-8320 communicates with either the VXI-MXI-2 or VME-MXI-2
or with another device in the chassis. The
VXI (VME)
LED, when lit,
indicates that the VXI-MXI-2 or VME-MXI-2 is acting as a slave to
another device in the VXI (VME) chassis, such as when a bus master inside
the chassis wants to talk to either the VXI-MXI-2 or VME-MXI-2 or
another device outside the chassis.
Are the VXI-MXI-2 and PCI-MXI-2, PCI-MXI-2 Universal, or
PXI-8320 two devices or one with respect to the VXIbus?
The PCI-MXI-2, PCI-MXI-2 Universal, PXI-8320, and VXI-MXI-2 are
unique VXIbus devices with their own logical addresses. However, the
MXIbus allows the PCI or PXI/CompactPCI computer to behave as if it is
inside the chassis with the VXI-MXI-2 by transparently converting PCI bus
cycles to MXIbus cycles to VXIbus cycles, and vice versa.
I have a system that requires rugged chassis and bulkhead cables. Can
I still use MXIbus?
Yes, National Instruments sells MXIbus bulkhead cables. Contact National
Instruments for further information.
What kind of signal is CLK10 and what kind of signal do I need for an
external CLK10?
CLK10 is a differential ECL signal on the VXIbus backplane. However, the
oscillator for the VXI-MXI-2 and the EXTCLK input from the front panel
use TTL. Therefore, supply a TTL-level signal for EXTCLK; the voltage
converters will convert the signal to differential ECL.
CLK10 is not applicable to VME.
