by aolofsson » Sat Mar 29, 2014 8:34 pm
Calle,Thanks, this is really helpful!
That fact that the self test passes means that the chip is more or less OK which is a good thing...but it makes the problem more frustrating.
Can you confirm that the matmul test does run correctly sometimes?
When it does fail, does it always fail the same way?
Which supply and cable are you using? Your own or the one from the accessory kit? Can you show a picture of your setup?
Does the board setup make a difference (ethernet only vs USB+hdmi+ethernet) for example.
Here are some theories ranked from likely to unlikely:
1. Power supply issue.
2. Operator error in the manufacturing line (we have now automated the testing procedure further to reduce the chance of operator error)
3. We "got lucky" in our production test (it only ran once)
4. We missed a subtle failure mode in our production tests.
5. The board was damaged due to overheating (we have not seen this yet..but 95 deg is out of spec for the zynq part).
Thanks for helping us figure out this failure mode!! Anything we learn will be immediately fed back to the production line and will ensure that the remaining 4,800 KS boards (out of 6,300) don't have this issue.
Andreas