While it's reasonable to presume that a finger will not normally be introduced into the operating environment of a microcontroller system, it does happen from time to time and, if it's at all likely, measures should be taken to prevent the finger, among other things, from contacting the MCU board.

I've done a limited amount of fiddling with the notion of controlling the rise and fall of Vcc, using transistors to pull down Vcc to the MCU whenever RESET goes active, but I've not convinced myself that all the bases are covered when that's done. Given a means to limit the rise and fall times of Vcc to the MCU to a few microseconds, an RC reset to the MCU with a very short time constant, just long enough to meet the minimal requirements of the MCU on startup, and less than 10 microseconds on RESET when Vcc is nearly at its nominal value, would probably be sufficient, IMHO. Maybe a supervisor IC would be cheaper. I doubt that it's a complete solution, though. Many 805x users believe it is, however.

I have an EVK for a cousin of your MCU, but mine's smaller one so I don't know that any experimentation on my board would shed any light on your problem. I have lots of other EVK's, but they're not SiLabs' and not in a modern package.

RE