Restriction on serial pins because of boot loader

This question has probably been asked hundreds of times before, but I haven't figured out to search for the answer.

So here's the question. I am using the standard arduino board, with USB to the computer, and am thus loading code through the serial pins, 0 and 1. I have a pin-hungry application, so I want to those pins as input pins in my app. I will set them to internal pullup, and no hardware activity should occur to them except through button pushes, which won't occur during programming.

So, in effect, during programming, they should have no loads on them at all. Does this indicate that I can put them to such a use and also use them for bootloading?

Thanks for any help with this.

I see no problem with that, effectively you have no hardware connected as long as you don't press a button.


As stated you can use pins 0 and 1 like you defined. To be extra safe you could always wire 200 ohm series resistors between the pins 0 and 1 and your two external signal outputs so that even if the signals was low when serial data output was high the current would be below pin life threatening.