SAM3U Serial buffers OVERRUN


#1

When running the timing attack from tutorial B3-1 I get the following warning:

WARNING - SAM3U Serial buffers OVERRUN - data loss has occurred.

I can complete the tutorial, but I would like to understand what is going on there.

BTW, what is the preferred way to notify errata in the Wiki? I’ve noticed a couple of typos and information that was slightly changed (e.g. in the example code in the Appendix of B3-1 I had to change ‘ChipWhisperer-Lite’ to ‘NewAE USB (CWLite/CW1200)’)


#2

Hello,

The buffer overrun is when the SAM3U serial buffers can’t keep up - it’s not a critical error, but normally means some data was lost. It commonly happens when the terminal emulator window isn’t open, OR there is a ‘polling internal’ that is set too slow. The built-in serial port for the SAM3U is fairly basic & uses polling over USB, so it doesn’t have the same speed as a real USB-serial bridge (which gets additional buffering on the Windows side).

For wiki errors - flag an issue on github for now is easiest. I’ve been working on best way to do this (either allow open registrations, or possibly hold wiki backend in git such that people can more easily see/edit/change pages). We’ve been too backlogged to sort this out, as would like people to be able to also contribute updated pages directly.

Thanks!

-Colin


#3

I had this problem. I solved it, you can solve it with changing ADC clock/source like this:
CWChapture.cwp> Scope Setting tab> ADC clock>source> CLKGEN x1 via DCM