Hopefully the question is clear. I want to know if the ICSP header can be safely plugged into either the uno or the mega without issue, or if its presence when plugged into an uno would cause problems.
It will work with an Uno even with the ICSP header in place. In fact, I just tested that to make sure I was remembering correctly.
There are 100 ohm resistors on two of the SPI lines for stability, and when using an ICSP header, these resistors are effectively bypassed, but it still works. I have not had problems.
Thanks. This literally just occurred to me, and I wasn’t sure if adding the ICSP header was actually a mistake as I intended to use it on both platforms.