I see that none of the dev boards have any ESD protection on the USB ports. I have always used a USBLC6 on the data lines. Is there any built-in protection in the CPU that I am not aware of? I could find no references to this in the datasheets for the processors. I see you have 33ohm inline resistors on the SOM’s but no references for this with the processor versions.
I had the same question when I built our RAM board. I also used to have such ESD chips on USB.
This time, I’ve tried without them and, so far, I don’t see any issue. Perhaps it depends on the environment, the speed of communications and the overall quality of the USB device(s).
I do not even have the inline 33 ohm resistors.
The processor datasheet says you don’t need the 33 ohm resistors (they are built in).