STM32MP15 Standby Consumption And Wake Time

[ISeed]

Hello, all!

I'm ​looking into the STM32MP15 family. It seems to offer me everything I need, but I'm not sure about consumption, and can't understand the data sheet fully in this regard.

For minimal consumption that will still allow the MPU to continue working normally (without boot) after wake, it seems I need the standby with RAM retention.

1. Is this really the most efficient mode for this?

2. What is the consumption in this mode, in a way that will allow it to be woken by RTC and pin interrupt? It seems it's 90uA, but I'm not sure.

​3. How long does waking from standby mode take?

4. Does waking from standby mode allow the MPU yo continue working as if after sleep, with all volatile memory data it had previously?

Thanks!​

[PatrickF · Accepted solution]

1 - RETRAM (Retention RAM) optionally kept in STANDBY is intended to have fast wake up execution for Cortex-M4, don't know if it is what you expect.

2 - before STANDBY, Linux context is saved in external DDR which is the most consuming part in platform STANDBY (whatever DDR3/DDR3L or even LPDDR2/LPDDR3).

STANDBY with RETRAM and RTC/BackupRAM enabled is 96uA typ, and only 11uA if you don't need RETRAM. DDR3L is in the range of few tens of mW, and down to few mW for LPDDR2/LPDDR3.

Wake up from STANDBY could be issued using RTC or WKUP pins (see Power_overview#Wakeup_sources)

3 - Wake up for Cortex-M4 from Standby, using RETRAM for it's code is 2.55ms typical.

Wake up for Linux from STANDBY (when suspended to DDR), is in the range of 1 second (slightly more for Weston graphical interface).

4 - Cortex-M4 is restarting from RETRAM, it is up to you to manage your data saving in RETRAM.

Linux context is restored after STANDBY (i.e. all peripherals drivers are relaunched),

For more details, see Power_overview

[ISeed]

Thanks!