CW305: trigger trace shows on even if no encryption initiated

I am using CW305 with the default AES-128 bitfile provided by chipwhisperer. After uploading bitfile the trace of tigger pin (TP1) looks like below:

It looks like no matter what is done from PC’s end, trigger pin keeps toggling. Why is the case? It is very difficult to understand in my case that which is noise and which is actual encryption.

That looks like noise from your clock bleeding onto the trigger line. If those are the actual measurements it does seem rather high, but maybe you’re using a 10x probe?

At any rate, encryption is occurring when TP1 is at 3.3V.

I have double checked the probing; it was not using 10x probing. And when the encryption goes on, the magnitude remains same. I get the correct encryption as output so assuming trigger and done signals are passing appropriately. I wonder why i do not get 3.3 V at TP1 when the encryption is on going.

If you’re able to run our CW305 AES notebook, then your CW capture hardware is seeing a valid trigger.

If you don’t see TP1 going to 3.3V while the “Capturing traces” loop is running, then there is probably something wrong with the setup of the scope you’re using to look at TP1.

This is what it should look like: narrow ~1us pulses every ~20ms.

So for Trace Capture block, you are getting TP1 = 1 on around 20ms interval at 10MHZ?

Yes clock is 10 MHz. On my system captures run at around 50 iterations per second (YMMV – tnrange() will tell you what your capture rate is), which is why I see the trigger pulsing every 20ms.