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AVR "Reset" button?

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AVR "Reset" button?

By roach
-  Sat Mar 04, 2006 7:07 am #10668
Alright, so it's a dumb question. How do I add a "RESET" button to my Atmega128? Just put in a momentary tact on the RESET pin, tied to a pull-down resistor? This should bring the pin low, causing the uC to RESET, right?

By Vraz
-  Sat Mar 04, 2006 7:37 am #10670
Mostly. You don't need (or want) a pulldown resistor. Remember that reset has a pullup on it. So just connect reset to the switch to ground. You might want to add a small cap (100nf or so) across the switch to debounce it.
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By roach
-  Fri Mar 10, 2006 11:34 am #10860
Vraz wrote:Remember that reset has a pullup on it.
Is this internal to the ATmega? Where can I find this information in the datasheet?

thanks for the help.

By Vraz
-  Fri Mar 10, 2006 8:31 pm #10902
Is this internal to the ATmega? Where can I find this information in the datasheet?
Look at figure 22 (Reset Logic) in the complete datasheet. It shows the pull-up resistor there on the ~RESET pin.
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