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Best way to combine reset signals for STM32

Question asked by Gabriel Ballesteros on Oct 14, 2017
Latest reply on Oct 14, 2017 by Clive One



I have a design that has two STM32s in it, for this application I would like them to be able to reset each other. On top of that, there would be the physical reset button and the SWD reset signal.


What is the "standard" solution? I have looked into OR gates, reset supervisor ICs with manual trigger, and analog switches.


I am aware the NRST pin uses CMOS.


Clive One , if you see this post you probably have the right answer as you have advised in a couple of posts to be careful not to use other push-pull drivers Micro only starts with debugger or nRST manually pulled low :

You don't want any other push-pull drivers on the pin, the pin should have it's own pull-up.


Another potential issue would be the continuous "ping-pong" reset between the two STM32s, but the datasheets specifies the following:

In order to improve the consumption under reset, the I/Os state under and after reset is “analog state” (the I/O schmitt trigger is disable). In addition, the internal reset pull-up is deactivated when the reset source is internal.

So this does not seem to be an issue, but if there's a caveat, please chime in.