I am trying to write a loopback test for my USB JTAG board I bought from Mesa Electronics. I keep having problems with getting repeating bytes coming back from the board when I read back. Sometimes I can only go a few bytes without errors and sometimes I can go serveral thousand bytes before I get an error.
My test bench in verilog seems to be okay and behaves as expected, but things do not work correctly when I run from the board. I used some usb sniffing software to verify that the dupes are coming from the board and not from my driver software.
Ideally it would be nice to know if someone else has written similar code and might even be able share it.
For the moment I totally stumped as to what the problem is. I will be happy to post the code I have written so far if anyone is interested in looking it over.