Sleep Mode Description

[misterlisty]

How does sleep work, help doc doesn't explain it? When the device goes to sleep, what memory is retained? Does it continue from where it left off or restarts boot & main. Did I miss the doco for this?

[jcaron]

@misterlisty If you mean deep sleep, in all cases, all CPU memory and CPU state is lost, and on wake-up it's like the module was just powered on.

This is in the docs, though it's perhaps not that clear.

For machine.deepsleep:

https://docs.pycom.io/firmwareapi/pycom/machine/#machinedeepsleeptimems

Stops the CPU and all peripherals, including the networking interfaces (except for LTE). Execution is resumed from the main script, just as with a reset.

Note that at the ESP32 level the RTC domain including its memory is kept active, but there's no support for that at the micropython level.

In the case of Pysense/Pytrack/Deep Sleep Shield-controlled deep sleep, it's even worse, as power to the ESP32 is cut.

[Paul Thornton]

The wording on that isnt brilliant. but yes. it restarts from the top of main.py again. ill update the docs to be clearer

[jcaron]

@paul-thornton To be precise, it actually starts from the top of boot.py :-)

While you're in the docs, I don't think the read_battery_voltage method for the Pysense/Pytrack/etc. is in the docs, you may want to add that as well.

[misterlisty]

From what i read above, it would also restart boot.py?

[jcaron]

@misterlisty Yes, it acts exactly as on a power on, it executes boot.py then main.py.

The only way to know whether it's a power on or a wake from sleep (and what the reason for the wake up was) is to call machine.wake_reason.

The possible reasons are listed in the constants at the bottom of the page: machine.PWRON_WAKE, machine.PIN_WAKE, machine.RTC_WAKE, machine.ULP_WAKE.

[Paul Thornton]

@jcaron said in Sleep Mode Description:

@paul-thornton To be precise, it actually starts from the top of boot.py :-)
While you're in the docs, I don't think the read_battery_voltage method for the Pysense/Pytrack/etc. is in the docs, you may want to add that as well.

Thanks ill get this added today if its missing.