ESP32 Forum

Maybe if you manually tweak the correct rtc registers you can cause a wake event. Then you could set a flag in rtc memory that is checked by the main CPU.

@igrr, are you back from vocation now? would you please help here?

I'm working on an example of deep sleep wakeup modes, ulp wakeup included. As soon as I get either ADC or TSENS working, will put this into a branch for you to try.

Any good new on this example? @ESP_igrr

deep sleep / ULP example is finished, but we're only going to merge it after 2.0. Currently it polls the on-chip temperature sensor, but I also have some code for polling an ADC which I will integrate in there.

I would be eager to see some pre-release if you don't mind...it doesn't need to be in pretty format...my project was stuck due to current ULP are not able to read GPIO input through RTC_GPIO_IN_REG. I'm trying to find out if using ADC can be a viable work-around.

deep sleep / ULP example is finished, but we're only going to merge it after 2.0. Currently it polls the on-chip temperature sensor, but I also have some code for polling an ADC which I will integrate in there.

Sorry, I haven't noticed your last message. The deep sleep example is now on Github, and i think it answers some questions you have asked above. Also there are some bugfixes which have been merged, related to access to RTC registers, so you should be able to read GPIOs from the ULP now.
Extending the example to illustrate ADC sampling is work-in-progress, as is the integration of ULP binutils into the ESP-IDF.