Waking up from sleep.

[Carel]

Hi,

To save power our system goes into off mode.

rtcwake -s 60 -m off

1	rtcwake -s 60 -m off

This works as expected and the system returns from “sleep” when the rtc alarm goes off (60 seconds in the above example). The problem comes in when trying to wake the system using GPIOs (Ive tried PC13 and nPONKEY, neither of them work when sleep is initiated by rtcwake or shutdown).

1. nPONKEY works on its own. A 10 second keypress shuts the system down and a normal keypress turns it back on again.
2. When shut down using nPONKEY the system also wakes when triggering PC13.

Could this be a PMIC issue? From what I understand the PMIC will only action the nPONKEY event if it is an OFF state.

 

Regards,

 

 

[Eshtaartha Basu]

Hello Carel,

Asserting nPONKEY and WAKEUP (PC13) do not work in your use case because your PMIC is in ALTERNATE (Low Power) mode and not in OFF state/NO_SUPPLY state since PWR_ON/PMIC_PWRCTRL pin is asserted by RTC.

As indicated by PMIC datasheet, the STPMIC1 offers 2 independent POWER_ON modes called MAIN and ALTERNATE.
Switching between these modes is driven by the application processor through PWRCTRL pin.

See highlighted sentences of the attached screenshots from the official documentation for more information. If you have access to PWR_ON/PMIC_PWRCTRL pin on your board, you can probe it to see how its state changes between “sleep” and “wake-up”.

• This reply was modified 1 year, 4 months ago by Eshtaartha Basu.

Attachments:

1. 

   pmic_turn_on_conditions.png
   

2. 

   pmic_power_on_modes.png
   

3. 

   AN5109_low_power_entry_exit_ctrl.png
   

[coloradocarlos]

Carel,

The other thing you should check is to make sure the pwr_regulator node in the TF-A device tree is what your want.

system_off_soc_mode can be either <STM32_PM_SHUTDOWN> or <STM32_PM_CSTOP_ALLOW_STANDYBY_DDR_OFF>.

Carlos

[Author]

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