ESP32 Forum

Apologies if this has already been asked.
Is it possible to re-enter deep sleep from within esp_wake_deep_sleep()?

Obviously I've tried, but if I call without even trying to call I get an Am I just being stupid and this isn't accessible from within an RTC_IRAM_ATTR function?
or is it more complex?
or is it a bug?

The wake stub code can only call functions implemented in ROM or loaded into RTC Fast Memory

https://docs.espressif.com/projects/esp ... -stub.html

Still trying to get a handle on this .. hope people don't mind me adding findings here

ROM functions can be found in
https://github.com/espressif/esp-idf/tr ... nclude/rom

sleep related functions can be found in
https://github.com/espressif/esp-idf/bl ... ep_modes.c

So I guess it's going to be a case of copying the necessary code from sleep_modes.c, or maybe delving into ULP!

*deleted a long section based on me thinking IRAM was the same as RTC_IRAM*

There's sample code that does exactly this:

https://gist.github.com/igrr/54f7fbe051 ... d7fbecfeab

That code was brill ... its a PITA to try to find exactly what you can and can't call though, you have to poke through the source looking for the IRAM tag.

For what it's worth in case anyone cares.

I'm finding that it takes around 1mSec from when I see the current begins to ramp up before my wake_stub code raises an IO line high.