ESP-WROOM-32 doesn't wake from lightsleep on timer

[kebwi]

Light sleep is pretty straightforward on my D1 Minis. When I tried similar code on an ESP-WROOM-32, the device never woke up. All I'm doing is calling this:

machine.lightsleep(sleep_duration_ms) # e.g., 1000 to sleep for one second

Just in case there some confusion about units and passing large values was actually indicating seconds instead of milliseconds, I've also tried calling it with very small numbers, such as 1. I never get the terminal prompt back, nor does the device reboot or otherwise rerun main from the top, as would be expected from deepsleep, which I'm not testing anyway. It simply hangs after calling lightsleep as shown above and must be reset with a physical push of the onboard reset button.

Do I need to tie some wake pin to some reset pin, as is necessary on some ESP8266 systems. Although that was only necessary for deepsleep anyway, not lightsleep. The ESP32 doesn't have clearly labeled wake or reset pins, although I'm practically certain the EN pin is the reset pin, but I still don't know which pin would be the wake pin. Some looking around suggest I might be able to configure any RTC GPIO as a wake pin tied to the EN pin -- but I still don't see why that would be necessary to merely make lightsleep work effectively? Should it just work directly from a single line of code, as above?

Thanks.

[robert-hh]

Just to complete the image, although it might not matter in you case: which firmware version do you use?
I just tried machine.lightsleep() with a WROOM equivalent board, Firmware 1.19.1-443, and it worked as expected,

[davefes]

I never get the terminal prompt back, nor does the device reboot or otherwise rerun main from the top, as would be expected from deepsleep, which I'm not testing anyway.

lightsleep just picks-up where it left off. So, it doesn't reboot or re-run main. I have two ESP32-WROOM boards running 1.18 and I think rshell does come to life and show you that things have started again after a lightsleep. I find it very helpful to have a "heartbeat" LED in the main loop.

[kebwi]

Mine doesn't wake up. I'll keep fiddling with it. Thanks.

[fivdi]

Are you by any chance using the WebREPL? If so, calling machine.lightsleep() from the browser window will result in the browser loosing the connection to the ESP32 and it will look like everything is broken.

Calling machine.lightsleep() from the REPL via the USB port works for me.

If you are not using the WebREPL I would suggest posting a complete program that can be used to reproduce the problem. Please post the complete content of boot.py too. A link to the type of board being used might help too.

[davefes]

https://docs.micropython.org/en/latest/library/esp.html
I am a bit confused as it talks about SLEEP_LIGHT not lightsleep(). However, I understood that the ESP32 did not remember the connection, so never tried otherwise.

There has been some recent discussion on whether or not the ESP32 will try to reconnect when it is brought back up. karfas showed me that there is a WLAN.config(reconnect=N) available.

https://github.com/orgs/micropython/discussions/10029

Generally, I have the opposite problem and try to ensure that the ESP32 is NOT connected to anything when I re-boot. To ensure that things always start up at square-one I do a poweron_reset() see https://github.com/orgs/micropython/discussions/9345

[kebwi]

The function call is machine.lightsleep().

EDIT: Perhaps, umm, were you suggesting I'm using the wrong function to put the device to sleep? Were you recommending a different approach? Thanks.

[kebwi]

Thanks for the ref to WLAN.config(reconnect=N).

[davefes]

No, just didn't put machine in front of it.

[davefes]

In my watering timers I do:

while True:
    make STA active true
    connect to it

    do my processing

    disconnect from it
    make STA active false

    lightsleep(x)

Part of my connect function is always to make sure that the ESP32 is disconnected:

    if sta_if.isconnected():
        sta_if.disconnect()
        print ('started in the connected state')
        print ('but now it is disconnected')
    else:
        print ('started in the disconnected state')