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Using Arduino => Microcontrollers => Topic started by: Fuzzietech on Nov 13, 2017, 08:35 pm

Title: What do I do with the leftover Reset pin?
Post by: Fuzzietech on Nov 13, 2017, 08:35 pm
Hi guys!

  So I have been tinkering a lot with ATTINY circuits and building PCBs around them. All works like a charm so far, but I got me thinking about the Reset pin.

  What is the proper way to "treat" it? I mean so far I have always just left it open-ended not connected to anything at all. Mostly because I do not need a reset button on any of my projects.

  Can I just continue to leave it N/C? Or is there a "proper" way I should still connect it even if I do not intend to use it?

  Thanks so much in advance!
Title: Re: What do I do with the leftover Reset pin?
Post by: Coding Badly on Nov 13, 2017, 08:40 pm

The internal resistance is very weak.  If you leave RESET enabled you have to add something external (e.g. 10 k ohm resistor) to hold it high.  I know for a fact static electricity can cause spurious resets from an unconnected RESET pin.

(I tie RESET to VCC in my final versions.)

Title: Re: What do I do with the leftover Reset pin?
Post by: ron_sutherland on Nov 13, 2017, 09:58 pm
Does the ATTINY have a high voltage programming mode? The reset on the AVR's I have been using (328p, 1284p) lack a high side ESD diode so they can go over 12V and activate that programming mode.
Title: Re: What do I do with the leftover Reset pin?
Post by: Coding Badly on Nov 13, 2017, 10:12 pm
Does the ATTINY have a high voltage programming mode?
The ones I use do (tX5, tX4).

Title: Re: What do I do with the leftover Reset pin?
Post by: jaa101 on Sep 16, 2020, 04:19 am
There's an internal pull-up on the RESET pin (30k--60k according to the specs) so leaving it with no connexion is fine.
Title: Re: What do I do with the leftover Reset pin?
Post by: pourduino on Sep 16, 2020, 09:29 pm
Pull it up with a 10k resistor.
Title: Re: What do I do with the leftover Reset pin?
Post by: CrossRoads on Sep 16, 2020, 09:34 pm
Especially in a "noisy" enviroment. Recommended in the App notes.