1. Article purpose[edit | edit source]
The purpose of this article is to give an overview of the software APIs available on the Arm® Cortex®-M (also named MCU) side to handle the low power modes, acting as coprocessor .
2. Low power modes available on the chip[edit | edit source]
The low power modes are handled by RCC and PWR peripherals.
See Platform power overview for mode description or refer to the STM32 MPU reference manuals the full description of the modes.
2.1. Wakeup sources[edit | edit source]
The low power modes are left due to a wakeup event. It can be configured by setting the wakeup control feature of the IP and activating the corresponding EXTI on MCU side.
The wake sources are listed in the Platform power overview page.
3. Software overview[edit | edit source]
- STM32MP15x lines
- The power HAL is used to select the Cortex-M4 low power mode.
- Further information on HAL can be found here: STM32CubeMP15 Package architecture
- STM32MP2 series
- The power HAL is used to select the Cortex-M33 low power mode when it is running in internal RAM.
- The Cortex-M33 low power is not supported when the MCU firmware is running in DDR, the firmware need to be stopped and the associated resources need to be released before requesting low power mode on MPU side with Linux (see Power overview for detail)).
- Further information on HAL can be found here: STM32CubeMP2 Package architecture
3.1. APIs description[edit | edit source]
The STM32MP15x lines power HAL supports the following APIs related to power management:
HAL_PWR_EnterSLEEPMode: CSleep mode is enteredHAL_PWR_EnterStopMode: CStop mode is entered allowing Stop as the deepest platform low power modeHAL_PWR_EnterStandbyMode: CStop mode is entered allowing Standby as the deepest platform low power mode
4. Code source location[edit | edit source]
STM32CubeMP15 Package provides
- power HAL driver:
- EXTI driver: Drivers/STM32MP1xx_HAL_Driver/Inc/stm32mp1xx_hal_exti.h
STM32CubeMP2 Package provides:
- power HAL driver:
- EXTI driver: Drivers/STM32MP2xx_HAL_Driver/Inc/stm32mp2xx_hal_exti.h
Arm® is a registered trademark of Arm Limited (or its subsidiaries) in the US and/or elsewhere. 
Arm® is a registered trademark of Arm Limited (or its subsidiaries) in the US and/or elsewhere.