Hi,
I was following @Laurids_PETERSEN post on his low power ThreadX example (Part 2 ThreadX Low power Project ).
I noticed his sample code, Snippet 11 on Enter Low Power mode configured the APB ENR, AHB ENR in RUN mode and then disabled all the peripheral clocks in the APB SMENR and AHB SMENR for STOP Mode. In previous STM32Cube examples I have never seen this being done before.
I would like to know what is recommended steps when entering low power mode. I thought I should just enable on the peripheral clocks I need to run in STOP mode e.g. if my only wakeup sources are a GPIOF pin and the RTC wakeup source then I would just enable only those peripheral clocks in STOP mode Enable register. I have copied my enter Low Power Mode function below.
void SystemControlEnterLowPowerMode(void)
{
__HAL_RCC_PWR_CLK_ENABLE();
//Disables SRAM2 and SRAM3 retention in stop mode 2.
//Nothing is stored in SRAM2 and SRAM3
HAL_PWREx_DisableSRAM2ContentRetention();
HAL_PWREx_DisableSRAM3ContentRetention();
/* GPIO Ports Clock Enable */
__HAL_RCC_GPIOI_CLK_DISABLE();
__HAL_RCC_GPIOH_CLK_DISABLE();
__HAL_RCC_GPIOE_CLK_DISABLE();
__HAL_RCC_GPIOB_CLK_DISABLE();
__HAL_RCC_GPIOA_CLK_DISABLE();
__HAL_RCC_GPIOG_CLK_DISABLE();
HAL_PWREx_DisableVddIO2();
__HAL_RCC_GPIOD_CLK_DISABLE();
__HAL_RCC_GPIOC_CLK_DISABLE();
//__HAL_RCC_GPIOF_CLK_DISABLE(); //wakeup pin is on this port
//Enable only clocks needed during sleep mode
MODIFY_REG(RCC->AHB1SMENR, DUMMY_VALUE, RCC_AHB1SMENR_FLASHSMEN | RCC_AHB1SMENR_SRAM1SMEN );
MODIFY_REG(RCC->AHB2SMENR, DUMMY_VALUE, RCC_AHB2SMENR_GPIOFSMEN );
MODIFY_REG(RCC->AHB3SMENR, DUMMY_VALUE, 0 );
MODIFY_REG(RCC->APB1SMENR1, DUMMY_VALUE, RCC_APB1SMENR1_PWRSMEN | RCC_APB1SMENR1_RTCAPBSMEN);
MODIFY_REG(RCC->APB1SMENR2, DUMMY_VALUE, 0 );
MODIFY_REG(RCC->APB2SMENR, DUMMY_VALUE, 0 );
HAL_UART_DeInit(&hlpuart1);
/* Suspend sys ticks to avoid waking up the mcu on every interrupt */
HAL_SuspendTick();
/* Disable the Debug Module during STOP mode */
//HAL_DBGMCU_DisableDBGStopMode();
/* Enter Stop Mode */
HAL_PWREx_EnterSTOP2Mode(PWR_STOPENTRY_WFI);
}
