Question
Abnormal delta of TSC after exiting STOP mode
Hi,
MCU: STM32L072
MCU is using TSC and ST touch sense library. Before entering stop mode, the delta of touch key without pressing is normal (-2 to 2). However, after exiting STOP mode and then calling tsl_user_Exec_IT(), there is strange value delta.
But if system wait ~100ms after exiting STOP mode and then call tsl_user_Exec_IT(), the delta is normal.
I am using LPTIM interrupt (external 32.768kHz clock) to exit STOP mode.
Do you have any idea what is wrong?
Here is how system enter and exit stop mode:
void EnterStopMode(void)
{
// Enable Ultra low power mode
HAL_PWREx_EnableUltraLowPower();
// Disable the fast wake up from Ultra low power mode
HAL_PWREx_DisableFastWakeUp();
// Select HSI as system clock source after Wake Up from Stop mode
__HAL_RCC_WAKEUPSTOP_CLK_CONFIG(RCC_STOP_WAKEUPCLOCK_HSI);
HAL_SuspendTick();
HAL_PWR_EnterSTOPMode(PWR_LOWPOWERREGULATOR_ON, PWR_STOPENTRY_WFI);
// In Stop mode
// Wake up
HAL_ResumeTick();
SystemClock_Config();
}void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
/** Configure the main internal regulator output voltage
*/
__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
/** Configure LSE Drive Capability
*/
HAL_PWR_EnableBkUpAccess();
__HAL_RCC_LSEDRIVE_CONFIG(RCC_LSEDRIVE_LOW);
/** Initializes the RCC Oscillators according to the specified parameters
* in the RCC_OscInitTypeDef structure.
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI|RCC_OSCILLATORTYPE_LSI
|RCC_OSCILLATORTYPE_LSE;
RCC_OscInitStruct.LSEState = RCC_LSE_ON;
RCC_OscInitStruct.HSIState = RCC_HSI_DIV4;
RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
RCC_OscInitStruct.LSIState = RCC_LSI_ON;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
/** Initializes the CPU, AHB and APB buses clocks
*/
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI;
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_0) != HAL_OK)
{
Error_Handler();
}
PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_LPUART1|RCC_PERIPHCLK_LPTIM1;
PeriphClkInit.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_SYSCLK;
PeriphClkInit.LptimClockSelection = RCC_LPTIM1CLKSOURCE_LSE;
if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
{
Error_Handler();
}
}