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STM32WB: Enter STOP2 Mode and Wake-Up via EXTI, Ensuring Peripheral Continuity
I'm currently working on an STM32WB project and would appreciate guidance on the correct sequence to enter STOP2 low-power mode and wake up via an EXTI interrupt, ensuring all peripherals resume normal operation post-wake-up.
Specifically, I’m looking for:
The recommended steps to enter STOP2 mode, including any pre-conditions or configurations.
The proper configuration for EXTI-based wake-up (I’m using a GPIO line for this).
Best practices to ensure that all necessary peripherals (UART, SPI, ADC, USB, etc.) are correctly restored after wake-up.
Any important considerations related to Core 2 (BLE stack), clock sources, or peripheral clocks that should be handled manually before or after STOP2.
I’ve reviewed the reference manual and some ST examples, but a consolidated, recommended sequence or reference to an app note/code example that handles these aspects cleanly would be very helpful.
Thank you in advance for your support!
Refrence code:
int main(void)
{
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* Config code for STM32_WPAN (HSE Tuning must be done before system clock configuration) */
MX_APPE_Config();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* Configure the peripherals common clocks */
PeriphCommonClock_Config();
/* IPCC initialisation */
MX_IPCC_Init();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_RF_Init();
MX_GPIO_Init();
MX_DMA_Init();
MX_LPUART1_UART_Init();
MX_RTC_Init();
MX_SPI1_Init();
MX_ADC1_Init();
MX_I2C1_Init();
MX_USART1_UART_Init();
MX_RNG_Init();
/* USER CODE BEGIN 2 */
MX_USB_Device_Init();
/* USER CODE END 2 */
/* Init scheduler */
osKernelInitialize();
/* Init code for STM32_WPAN */
MX_APPE_Init();
/* Call init function for freertos objects (in cmsis_os2.c) */
MX_FREERTOS_Init();
/* Start scheduler */
osKernelStart();
/* We should never get here as control is now taken by the scheduler */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}
/**
* @brief System Clock Configuration
* @retval None
*/
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
/** Configure LSE Drive Capability
*/
HAL_PWR_EnableBkUpAccess();
__HAL_RCC_LSEDRIVE_CONFIG(RCC_LSEDRIVE_MEDIUMHIGH);
/** Configure the main internal regulator output voltage
*/
__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
/** Initializes the RCC Oscillators according to the specified parameters
* in the RCC_OscInitTypeDef structure.
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI|RCC_OSCILLATORTYPE_LSI1
|RCC_OSCILLATORTYPE_HSE|RCC_OSCILLATORTYPE_LSE
|RCC_OSCILLATORTYPE_MSI;
RCC_OscInitStruct.HSEState = RCC_HSE_ON;
RCC_OscInitStruct.LSEState = RCC_LSE_ON;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.MSIState = RCC_MSI_ON;
RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
RCC_OscInitStruct.MSICalibrationValue = RCC_MSICALIBRATION_DEFAULT;
RCC_OscInitStruct.MSIClockRange = RCC_MSIRANGE_6;
RCC_OscInitStruct.LSIState = RCC_LSI_ON;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_MSI;
RCC_OscInitStruct.PLL.PLLM = RCC_PLLM_DIV1;
RCC_OscInitStruct.PLL.PLLN = 32;
RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
RCC_OscInitStruct.PLL.PLLR = RCC_PLLR_DIV2;
RCC_OscInitStruct.PLL.PLLQ = RCC_PLLQ_DIV2;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
/** Configure the SYSCLKSource, HCLK, PCLK1 and PCLK2 clocks dividers
*/
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK4|RCC_CLOCKTYPE_HCLK2
|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;
RCC_ClkInitStruct.AHBCLK2Divider = RCC_SYSCLK_DIV2;
RCC_ClkInitStruct.AHBCLK4Divider = RCC_SYSCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_3) != HAL_OK)
{
Error_Handler();
}
/** Enable MSI Auto calibration
*/
HAL_RCCEx_EnableMSIPLLMode();
}
/**
* @brief Peripherals Common Clock Configuration
* @retval None
*/
void PeriphCommonClock_Config(void)
{
RCC_PeriphCLKInitTypeDef PeriphClkInitStruct = {0};
/** Initializes the peripherals clock
*/
PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_SMPS|RCC_PERIPHCLK_RFWAKEUP
|RCC_PERIPHCLK_USB|RCC_PERIPHCLK_ADC;
PeriphClkInitStruct.PLLSAI1.PLLN = 24;
PeriphClkInitStruct.PLLSAI1.PLLP = RCC_PLLP_DIV2;
PeriphClkInitStruct.PLLSAI1.PLLQ = RCC_PLLQ_DIV2;
PeriphClkInitStruct.PLLSAI1.PLLR = RCC_PLLR_DIV2;
PeriphClkInitStruct.PLLSAI1.PLLSAI1ClockOut = RCC_PLLSAI1_USBCLK|RCC_PLLSAI1_ADCCLK;
PeriphClkInitStruct.UsbClockSelection = RCC_USBCLKSOURCE_PLLSAI1;
PeriphClkInitStruct.AdcClockSelection = RCC_ADCCLKSOURCE_PLLSAI1;
PeriphClkInitStruct.RFWakeUpClockSelection = RCC_RFWKPCLKSOURCE_HSE_DIV1024;
PeriphClkInitStruct.SmpsClockSelection = RCC_SMPSCLKSOURCE_HSI;
PeriphClkInitStruct.SmpsDivSelection = RCC_SMPSCLKDIV_RANGE1;
if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN Smps */
/**
* This prevents the CPU2 to disable the HSI48 oscillator when
* it does not use anymore the RNG IP
*/
LL_HSEM_1StepLock( HSEM , CFG_HW_CLK48_CONFIG_SEMID);
/* USER CODE END Smps */
}