Stop2 mode in stm32l496zg is not working

[Dhiraj1]

I am working on stm32l496zg controller with freertos.

Now, i want to use stop2 low power mode

I am using HSE, LSI and LSE clock.

As per the reference manual HSE clock will be disabled when we enter in to stop2 mode and wake up

clock source could be HSI or MSI.

Before entering STOP2 mode i shift clock from HSE to HSI and i am ble to enter into the STOP2 mode.

But incould not be able to wakeup from the STOP2 mode and i suspect that there could be an issue

with the clock configuration.

Please could you help me for the clock configuration while entering & exiting from the STOP2 mode.

Sample code will be also helpful.

Please find below code which i am working on.

stop2 function which we using for Freertos:

void Enter_STOP_mode (void)

{

  printf("Enter in stop2 mode\r\n");

  HAL_SuspendTick(); // Suspend tick timer 

  Switch_to_HSI();

  HAL_PWREx_EnterSTOP2Mode(PWR_STOPENTRY_WFI);  

  printf("Exit in stop2 mode");

  SystemClock_Config();

  HAL_ResumeTick();

}

void Switch_to_HSI(void)

{

 RCC_OscInitTypeDef RCC_OscInitStruct = {0};

 RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

 RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};

 __HAL_RCC_PWR_CLK_ENABLE();

 /** Configure LSE Drive Capability

 */

 HAL_PWR_EnableBkUpAccess();

 __HAL_RCC_LSEDRIVE_CONFIG(RCC_LSEDRIVE_LOW);

 /** Initializes the CPU, AHB and APB busses clocks

 */

 RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI|RCC_OSCILLATORTYPE_LSI

               |RCC_OSCILLATORTYPE_LSE;

 RCC_OscInitStruct.LSEState = RCC_LSE_ON;

 RCC_OscInitStruct.HSIState = RCC_HSI_ON;

 RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;

 RCC_OscInitStruct.LSIState = RCC_LSI_ON;

 RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;

 RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;

 RCC_OscInitStruct.PLL.PLLM = 4;

 RCC_OscInitStruct.PLL.PLLN = 40;

 RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;

 RCC_OscInitStruct.PLL.PLLQ = RCC_PLLQ_DIV2;

 RCC_OscInitStruct.PLL.PLLR = RCC_PLLR_DIV2;

 if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)

 {

  Error_Handler();

 }

 /** Initializes the CPU, AHB and APB busses clocks

 */

 RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK

               |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;

 RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;

 RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;

 RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;

 RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

 if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_4) != HAL_OK)

 {

  Error_Handler();

 }

 PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_RTC|RCC_PERIPHCLK_USART1

               |RCC_PERIPHCLK_USART2|RCC_PERIPHCLK_USART3

               |RCC_PERIPHCLK_LPUART1|RCC_PERIPHCLK_I2C1

               |RCC_PERIPHCLK_I2C4|RCC_PERIPHCLK_USB

               |RCC_PERIPHCLK_SDMMC1|RCC_PERIPHCLK_ADC;

 PeriphClkInit.Usart1ClockSelection = RCC_USART1CLKSOURCE_PCLK2;

 PeriphClkInit.Usart2ClockSelection = RCC_USART2CLKSOURCE_PCLK1;

 PeriphClkInit.Usart3ClockSelection = RCC_USART3CLKSOURCE_PCLK1;

 PeriphClkInit.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_PCLK1;

 PeriphClkInit.I2c1ClockSelection = RCC_I2C1CLKSOURCE_PCLK1;

 PeriphClkInit.I2c4ClockSelection = RCC_I2C4CLKSOURCE_PCLK1;

 PeriphClkInit.AdcClockSelection = RCC_ADCCLKSOURCE_SYSCLK;

 PeriphClkInit.RTCClockSelection = RCC_RTCCLKSOURCE_LSE;

 PeriphClkInit.UsbClockSelection = RCC_USBCLKSOURCE_PLLSAI1;

 PeriphClkInit.Sdmmc1ClockSelection = RCC_SDMMC1CLKSOURCE_PLLSAI1;

 PeriphClkInit.PLLSAI1.PLLSAI1Source = RCC_PLLSOURCE_HSI;

 PeriphClkInit.PLLSAI1.PLLSAI1M = 4;

 PeriphClkInit.PLLSAI1.PLLSAI1N = 24;

 PeriphClkInit.PLLSAI1.PLLSAI1P = RCC_PLLP_DIV2;

 PeriphClkInit.PLLSAI1.PLLSAI1Q = RCC_PLLQ_DIV2;

 PeriphClkInit.PLLSAI1.PLLSAI1R = RCC_PLLR_DIV4;

 PeriphClkInit.PLLSAI1.PLLSAI1ClockOut = RCC_PLLSAI1_48M2CLK;

 if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)

 {

  Error_Handler();

 }

 /** Configure the main internal regulator output voltage

 */

 if (HAL_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1) != HAL_OK)

 {

  Error_Handler();

 }

}

Clock configuration for HSE,LSE,LSI attached:

void SystemClock_Config(void)

{

 RCC_OscInitTypeDef RCC_OscInitStruct = {0};

 RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

 RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};

 /** Configure LSE Drive Capability 

 */

 HAL_PWR_EnableBkUpAccess();

 __HAL_RCC_LSEDRIVE_CONFIG(RCC_LSEDRIVE_LOW);

 /** Initializes the CPU, AHB and APB busses clocks 

 */

 RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSI|RCC_OSCILLATORTYPE_HSE

               |RCC_OSCILLATORTYPE_LSE ;

 RCC_OscInitStruct.HSEState = RCC_HSE_ON;

 RCC_OscInitStruct.LSEState = RCC_LSE_ON;

 RCC_OscInitStruct.LSIState = RCC_LSI_ON;

 RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;

 RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;

 RCC_OscInitStruct.PLL.PLLM = 1;

 RCC_OscInitStruct.PLL.PLLN = 20;

 RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;

 RCC_OscInitStruct.PLL.PLLQ = RCC_PLLQ_DIV2;

 RCC_OscInitStruct.PLL.PLLR = RCC_PLLR_DIV2;

 if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)

 {

  Error_Handler();

 }

 /** Initializes the CPU, AHB and APB busses clocks 

 */

 RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK

               |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;

 RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;

 RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;

 RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;

 RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

 if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_4) != HAL_OK)

 {

  Error_Handler();

 }

 PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_RTC|RCC_PERIPHCLK_USART1

               |RCC_PERIPHCLK_USART2|RCC_PERIPHCLK_USART3

               |RCC_PERIPHCLK_LPUART1|RCC_PERIPHCLK_I2C1

               |RCC_PERIPHCLK_I2C4|RCC_PERIPHCLK_USB

               |RCC_PERIPHCLK_SDMMC1|RCC_PERIPHCLK_ADC;

 PeriphClkInit.Usart1ClockSelection = RCC_USART1CLKSOURCE_PCLK2;

 PeriphClkInit.Usart2ClockSelection = RCC_USART2CLKSOURCE_PCLK1;

 PeriphClkInit.Usart3ClockSelection = RCC_USART3CLKSOURCE_PCLK1;

 PeriphClkInit.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_PCLK1;

 PeriphClkInit.I2c1ClockSelection = RCC_I2C1CLKSOURCE_PCLK1;

 PeriphClkInit.I2c4ClockSelection = RCC_I2C4CLKSOURCE_PCLK1;

 PeriphClkInit.AdcClockSelection = RCC_ADCCLKSOURCE_SYSCLK;

 PeriphClkInit.RTCClockSelection = RCC_RTCCLKSOURCE_LSE;

 PeriphClkInit.UsbClockSelection = RCC_USBCLKSOURCE_PLLSAI1;

 PeriphClkInit.Sdmmc1ClockSelection = RCC_SDMMC1CLKSOURCE_PLLSAI1;

 PeriphClkInit.PLLSAI1.PLLSAI1Source = RCC_PLLSOURCE_HSE;

 PeriphClkInit.PLLSAI1.PLLSAI1M = 1;

 PeriphClkInit.PLLSAI1.PLLSAI1N = 24;

 PeriphClkInit.PLLSAI1.PLLSAI1P = RCC_PLLP_DIV2;

 PeriphClkInit.PLLSAI1.PLLSAI1Q = RCC_PLLQ_DIV4;

 PeriphClkInit.PLLSAI1.PLLSAI1R = RCC_PLLR_DIV4;

 PeriphClkInit.PLLSAI1.PLLSAI1ClockOut = RCC_PLLSAI1_48M2CLK;

 if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)

 {

  Error_Handler();

 }

 /** Configure the main internal regulator output voltage 

 */

 if (HAL_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1) != HAL_OK)

 {

  Error_Handler();

 }

}

[TDK]

You don't turn HSE off anywhere in Switch_to_HSI(). Not sure if this is required or not.

Check return value of HAL_RCC_OscConfig to make sure it's not HAL_ERROR. My guess is you can't switch from HSE PLL to HSI PLL in one step.

[Dhiraj1]

Hi TDK,

Thanks for your reply.

Now, I am able to successfully enter into the STOP 2 mode.

After wake-up, I have configured the clock to HSE with 80MHZ frequency and I have mapped clock frequency to MCO pin and measured the clock frequency which is not matching to 80 MHZ and because of that our other peripherals are not working properly.

Can anyone help me to understand what i am doing wrong here.

​Please find below code snippet for HSE clock configuration after wake up.

void SystemClock_Config(void)

{

 RCC_OscInitTypeDef RCC_OscInitStruct = {0};

 RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

 RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};

 /** Configure LSE Drive Capability 

 */

 HAL_PWR_EnableBkUpAccess();

 __HAL_RCC_LSEDRIVE_CONFIG(RCC_LSEDRIVE_LOW);

 /** Initializes the CPU, AHB and APB busses clocks 

 */

 RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSI|RCC_OSCILLATORTYPE_HSE

               |RCC_OSCILLATORTYPE_LSE ;

 RCC_OscInitStruct.HSEState = RCC_HSE_ON;

 RCC_OscInitStruct.LSEState = RCC_LSE_ON;

 RCC_OscInitStruct.LSIState = RCC_LSI_ON;

 RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;

 RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;

 RCC_OscInitStruct.PLL.PLLM = 1;

 RCC_OscInitStruct.PLL.PLLN = 20;

 RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;

 RCC_OscInitStruct.PLL.PLLQ = RCC_PLLQ_DIV2;

 RCC_OscInitStruct.PLL.PLLR = RCC_PLLR_DIV2;

 if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)

 {

  Error_Handler();

 }

 /** Initializes the CPU, AHB and APB busses clocks 

 */

 RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK

               |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;

 RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;

 RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;

 RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;

 RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

 if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_4) != HAL_OK)

 {

  Error_Handler();

 }

 PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_RTC|RCC_PERIPHCLK_USART1

               |RCC_PERIPHCLK_USART2|RCC_PERIPHCLK_USART3

               |RCC_PERIPHCLK_LPUART1|RCC_PERIPHCLK_I2C1

               |RCC_PERIPHCLK_I2C4|RCC_PERIPHCLK_USB

               |RCC_PERIPHCLK_SDMMC1|RCC_PERIPHCLK_ADC;

 PeriphClkInit.Usart1ClockSelection = RCC_USART1CLKSOURCE_PCLK2;

 PeriphClkInit.Usart2ClockSelection = RCC_USART2CLKSOURCE_PCLK1;

 PeriphClkInit.Usart3ClockSelection = RCC_USART3CLKSOURCE_PCLK1;

 PeriphClkInit.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_PCLK1;

 PeriphClkInit.I2c1ClockSelection = RCC_I2C1CLKSOURCE_PCLK1;

 PeriphClkInit.I2c4ClockSelection = RCC_I2C4CLKSOURCE_PCLK1;

 PeriphClkInit.AdcClockSelection = RCC_ADCCLKSOURCE_SYSCLK;

 PeriphClkInit.RTCClockSelection = RCC_RTCCLKSOURCE_LSE;

 PeriphClkInit.UsbClockSelection = RCC_USBCLKSOURCE_PLLSAI1;

 PeriphClkInit.Sdmmc1ClockSelection = RCC_SDMMC1CLKSOURCE_PLLSAI1;

 PeriphClkInit.PLLSAI1.PLLSAI1Source = RCC_PLLSOURCE_HSE;

 PeriphClkInit.PLLSAI1.PLLSAI1M = 1;

 PeriphClkInit.PLLSAI1.PLLSAI1N = 24;

 PeriphClkInit.PLLSAI1.PLLSAI1P = RCC_PLLP_DIV2;

 PeriphClkInit.PLLSAI1.PLLSAI1Q = RCC_PLLQ_DIV4;

 PeriphClkInit.PLLSAI1.PLLSAI1R = RCC_PLLR_DIV4;

 PeriphClkInit.PLLSAI1.PLLSAI1ClockOut = RCC_PLLSAI1_48M2CLK;

 if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)

 {

  Error_Handler();

 }

 /** Configure the main internal regulator output voltage 

 */

 if (HAL_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1) != HAL_OK)

 {

  Error_Handler();

}

}

[TDK]

> Now, I am able to successfully enter into the STOP 2 mode.

Okay, how did you solve it? Showing the answer helps others in the forum.

> measured the clock frequency which is not matching to 80 MHZ and because of that our other peripherals are not working properly.

Okay, what frequency is it? That should give you insight into the issue.

Are you checking that the return value is HAL_OK?

[Dhiraj1]

Hi TDK,

Thanks for reply.

For entering in STOP 2 mode we have to disable system tick and system tick interrupt in freertos.

All clock configuration functions return HAL_OK, but other peripherals eg. LPUART are not working.

can you please tell me why other peripherals are not getting clock after we get HAL_OK reply from all clock configuration functions?

Waiting for reply

[TDK]

I don't know. You're going to need to provide more info than that if you want to get help. Your original post didn't even mention that you're using FreeRTOS. Wouldn't you think that's an important detail?

[Dhiraj1]

Hi TDK,

Thanks for your quick reply.

But I have already mentioned in the original post that i am working on STM32L496ZG MCU with FreeRTOS. Please let me know what specific information you need.

[TDK]

Ahh, so you did. I missed that.

[Dhiraj1]

I am still struggling with the same problem of clock configuration after wake up from the STOP 2 mode.

It's quite urgent.

Any help on this is highly appreciated.

Thank you in advance..!!

[deckhard]

Is it really necessary to  HAL_SuspendTick before entering stop2 mode with freertos (not ticklessidle)?