How does the frequency of the target CPU affect my ability to do power analysis with the ChipWhisperer-lite. I see the max sample rate for CW-lite is 105MS/s. So does this mean that the maximum frequency of the target would be 1/2 of that (~50MHz) (Nyquist frequency) to be able to capture data at a high enough rate to do any power analysis if the CW-lite is not synchronized to the target clock?
What if I synchronize the target CPU clock with the CW-lite? What is the maximum target clock rate I could run my target at to be able to do power analysis? And is there a separate limitation of what the max synchronized clock rate that I feed into the CW-lite is?
ChipWhisperer isn’t really intended for asynchronous sampling. The signal you are trying to capture has a bandwidth many times higher than the clock frequency. It’s best to stick to synchronous sampling.
Depends on the target – for example I think the STM32 targets have a maximum clock spec of 24 MHz. So first look at your target’s datasheet. The CW-lite / pro sampling clock range is 3.2 MHz to 105 MHz.
Thanks for the response! What I mean to ask is what is the maximum frequency a target can run at to be able to reliable sample useful data for power analysis with the CW-lite? Say I have my own target that runs at X frequency and you cannot go below this frequency? How high can X go for CW-lite power analysis to work?