WARNING:root:Trigger not found in ADC data. No data reported!


#1

Hi,

I am using the CW lite with the XMEGA target and the CW5 jupyter notebooks.

I am using the basic capture loop as in the examples and I was already able to capture many traces.

Now, I started getting the following error: “WARNING:root:Trigger not found in ADC data. No data reported!”
Some more information:

  • The error only happens sometimes in the loop: In some iterations, scope.get_last_trace() returns nothing but in most iterations, scope.get_last_trace() returns a trace that looks like what I expected.

  • In all iterations, even the ones with the error, target.readOutput() returns a correct output

  • The error started occurring after I changed the c source file for the XMEGA. Many changes were made, but most notably, I added “#include <util/delay.h>” and use the function “_delay_us(100);” after the trigger. I do this to create an empty signal around my function, so that when I do the t-test, I can verify that there is no leakage in the signal-free zone. If i reduce the delay duration, the probability of the error also decreases.

Can you explain me why this error happens?
Is there a better way to create a pause after the trigger?

Thank you,
Lauren


#2

Hi Lauren,

I believe this might be caused by some modifications that we did to speed up capturing back in the fall. I’ve only seen it pop up when using large adc offsets (i.e. in the hundreds of thousands) and undoing one of the changes fixed it in that case.

I’ll try recreating the issue and, if I’m able to, I’ll let you know why it’s happening and what the fix is.

Alex


#3

An update on this issue:

Basically, what I think is happening here is that capture(), which is supposed to both wait for the trigger to activate and for the offset to pass, isn’t waiting for the latter. This causes it to try to read data before the offset has been reached, meaning the desired data doesn’t exist yet.

A shorter term fix should be available in the latest cw5dev branch. Basically, we just delay based on the adc offset.

Let me know if this fix works for you.

Alex