©
National Instruments Corporation
D-1
VXI/VMEpc 600 Series User Manual
D
Common Questions
This appendix answers common questions you may have when using the
VXI/VMEpc 600 Series.
What do the LEDs on the front of the VXI/VMEpc 600 Series mean?
Refer to Appendix B,
, for a description of the front panel
LEDs.
Is something wrong with the VXI/VMEpc 600 Series if the red SYSF
and FAIL LEDs stay lit after booting the VXI/VMEpc 600 Series?
If either the SYSF or FAIL LED remains lit, refer to Appendix B,
, for troubleshooting steps.
Can I access 32-bit registers in my VXI/VMEbus system from the
VXI/VMEpc 600 Series?
Yes. The VXI/VMEpc 600 Series uses the 32-bit PCI bus to interface to the
VXI/VMEbus. In fact, its VXI/VMEbus circuitry also supports the new
VME64 standard for D64 accesses.
What kind of signal is CLK10 and what kind of signal do I need for an
external CLK10?
♦
VXI Only—CLK10 is a differential ECL signal on the backplane.
However, the oscillator and the EXTCLK input on the front panel use TTL
levels; therefore, you need to supply a TTL-level signal for EXTCLK. Our
voltage converters convert the signal to differential ECL.
What is the accuracy of the CLK10 signal?
♦
VXI Only—The CLK10 signal generated by the VXIpc 600 Series is ±100
ppm (0.01%) as per the VXIbus specification. If you need a more accurate
CLK10 signal, you can use the external CLK connector on the front panel.