Confusion about power modes about m5epd HOT 2 CLOSED

Hello @RobertSmart

I think the confusion stems from what exactly you mean by sleep. I prefer to distinguish between the two ESP32 sleep modes (light sleep and deep sleep) and the device being in shutdown mode (in which everything is powered off except for the RTC).

For the ESP32 being in either light or deep sleep it still needs to be powered, else it never wakes up.

When the device is in shutdown mode (which I have a hunch is what you mean by sleep) only RTC or the power button can wake it up, but that is only true when running from battery. If USB is plugged in the device cannot go into shutdown mode - it is on all the time.

When you look at the sticker on the back of M5Paper you'll see something labelled MOS (FET). This is the main power switch and it can be activated by the power button, RTC, USB or the ESP32.

When the device is running from battery and is in shutdown mode and you press the power button that temporarily enables the MOSFET, the ESP32 boots up and then hold the enable for you so you can release the power button. The M5Paper is running until your code calls a shutdown method. (Or the battery runs out.)

However when USB is plugged in the MOSFET is enabled permanently. Or in other words, calling a shutdown method with USB plugged in has no effect - the M5Paper stays on.

So yes, the power button (jog button) can wake M5Paper when it has been put into shutdown mode on a timer, but as stated before that only works if running from battery.

The power button has two functions, it enables the MOSFET and it is also connected to a GPIO. So yes, if the M5Paper is in shutdown mode it will power it on and if M5Paper is running the power button can turn it off if (and only then) you have coded that in your application. By default the power button cannot turn off the M5Paper.

The main thing to understand is that testing shutdown mode, e.g. by calling a shutdown method can only work and be tested if M5Paper is not plugged into USB.

I hope this clears up some of your questions.

Thanks
Felix

from m5epd.

Thanks for the info Felix!

from m5epd.