03-10-2006 09:24 PM
03-13-2006 10:18 AM
03-13-2006 05:57 PM
Hi Ralph,
Dennis is correct, the PXI-8430 is limited to a maximum of 1 Mb/s. Here's a KnowledgeBase entry that explains why:
http://digital.ni.com/public.nsf/websearch/BA0652D1E13DBBC58625649F006561C2?OpenDocument
As noted at the end of the KB, the only way to "cheat" the baud rate is to modify the oscillator on the board. This is not something that is supported by National Instruments. You might find out what transceiver and oscillator frequency your DUT is using, and see if it might be possible to match those rates by matching the oscillator.
03-15-2006 09:45 PM
Thanks a bunch for the web-link with descriptive baud rate calculations vs. crystal frequencies. With a 66 MHz (commonly available freq (in fact that is what is used on the UUT)) crystal installed in my test setup, I should be able to hit 1.04 Mbaud within +/- few tenths of a percent. Should be close enough to disable my "spam generator" and let me communicate error-free. Faster comm = shorter test time!
With the same crystal I'll be able to hit 115.729 kbaud which is close to the other baud rate (115.2 kbaud) I would like to nail. If that doesn't get me close enough, I'll just get another PXI-843/4 and leave one unmodified.
Many thanks,
Ralph
03-16-2006 10:57 AM
Hi Ralph,
Before you go changing the crystal, you might want to make you you have tried the latest serial driver:
This version might let you cheat the baud rate up a little. I would definitely try this before making any drastic, and possibly damaging, hardware modifications.
03-16-2006 11:15 AM
Nevermind. Please disregard that last post. I tried an 8430 here with NI-Serial 3.0 and it limited the baud rate to 1 MBaud.
I still want to emphasize that modifying your 8430 will void any waranty, and you do so at your own risk.
06-06-2006 07:09 AM