Does Serial.begin make pins 0 & 1 unusable as I/O?

I am using Serial.begin(9600) to communicate through the USB port to run AppleScripts. That part works fine.

However, this seems to make pin 1 unusable when configured as pinMode(whatever, INPUT) for an external switch.

I have searched the docs and this forum, but have not found an answer.

Does running Serial.begin automatically set up pins 0 &1 as a serial port?

If so, can this be changed?

Thanks,

Neal

The serial I/O you’re using goes through pins zero and one.

You can use them for I/O, but not at the same time as you’re using them for serial.

I suspected that was the case.

I appreciate your time - thanks.