I made the very stupid mistake of hot plugging stuff many times before. My problem is that I rushed and it's just so easy for me to forget I have the Arduino on or some other expensive IC or hardware plugged in.
Today I hotplugged the PWM input of my ESC to my Arduino digital pin. I saw the magic smoke escape. Bye bye a group of digital pins! I hate myself now.
Why do things not like being hot plugged?
Is there an easy way I protect against this?
Best Answer
Two other effects, in addition to these already mentioned, can upset very delicate circuitry:
-Shielded cables and coaxial cables are actually capacitors, which can hold a charge. This charge can be misinterpreted as a signal and cause unwanted state changes (eg a processor crash), or even...
-Latchup. With the IC powered, some types of unprotected CMOS inputs cannot stand any voltage above the supply voltage even for microseconds, since this will trigger a positive feedback effect (the whole device suddenly looks like a thyristor with these voltages applied) leaving the device in a crashed state or even acting as a near short circuit across its supply rails.