Communicating with baud rate

Hi everyone,

I was trying to glitch a third party board but I met a problem.

I don’t understand something about the formula : “target.baud = 38400*24/7.37” taken from the tutorial example (Jupyter Notebook side).

I would like to communicate with my new target and his “simpleserial” communicating module. The problem is the following, I can’t change the HSI to 7,37Mhz. The actual HSI is clocked on 64 Mhz.

What change I’ve to make into my formula for being able to communicate with my target at 38400 bauds ?

Thanks by advance !

When built for simpleserial v1, our targets’ UART operate at 38400 bps when they’re clocked at 7.37 MHz (this could be changed in the target FW, but this is what’s done for e.g. simpleserial-aes). This baud rate scales linearly with the targets’ clock frequency; if you double the target clock to 14.74 MHz, you’ll find that the UART baud rate has increased to 76800, and you’ll have to set target.baud accordingly in order to successfully communicate. Setting target.baud instructs your ChipWhisperer capture hardware what baudrate to use to talk to the target. Your example shows the baud rate being set for a target that is clocked at 24 MHz.

For your third-party target, set target.baud to whatever its baud rate actually is.