Arduino: Reset with switch and/or 3.3v

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Joined Mar 25, 2012
I'm trying to interface a 3.3v microcontroller with an arduino running at 5v. Pin 1 on the 'duino is the reset line and it's active low. Standard arduino design has a 10k pullup on pin 1 (to +5v). When you want to reset the arduino, you ground pin 1. I believe the arduino considers anything below approximately 0.6v as a logic 0.

I'd like to keep the grounding switch, but add the ability for the 3.3v microcontroller to _also_ reset the 'duino by going to a logic 0. What is the best way to do this?? OR gate?? MOSFET on 3.3v line?? Two different pullup resistors with different values??

Appreciate the help!!!