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Reset vs Power Cycling

Posted: Sun Jun 24, 2018 4:38 am
by ashare
Hi,

I am curious to know if there exists any difference between toggling the Enable (EN) signal on the ESP32 WROOM module and cycling the power to the module. Are there any faults which are cleared only by cycling the power? This post on Github is the source of my confusion.

An excerpt from the post is reproduced below:
Sometimes a simple reboot fixes the problem, but generally, the power cycle is required.
Thanks in advance.

Ashare

Re: Reset vs Power Cycling

Posted: Mon Jun 25, 2018 10:48 am
by novalight
Hi, I am also interested in this. Also maybe: what are the differences between calling esp_restart() / esp_reboot() and EN-toggle?

Re: Reset vs Power Cycling

Posted: Tue Jun 26, 2018 12:00 am
by ESP_Angus
I think the "simple reboot" in this case is probably a software reset, at least this is how I read it.

The are some differences between hard resets (power cycle or EN pin toggled) and soft resets. The ESP32 TRM gives some details about the different subsystems reset in each case.

Ideally, a reset via esp_restart() (or Arduino ESP.restart(), which is the same thing) should be functionally equivalent to a hard reset in terms of resetting core hardware like the WiFi subsystem. Although some of this is done in software by esp_restart() disabling some subsystems before it triggers the soft reset. If this doesn't happen cleanly, it's a bug.

For resets due to crashes, some subsystems may keep running until ESP-IDF restarts and resets them. However also in this case, any problems with subsystems like WiFi is also due to a bug (it should be able to recover from any reset case).

Will comment on the GitHub issue as well.

Angus