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TIMx become slow when enable ULP (STM32L071RB)

Question asked by dz huang on May 31, 2018
Latest reply on Jun 1, 2018 by dz huang

My current project using STM32L071RB chip, and now encounter a strange issue, when I enable PWR_CR ULP bit thr "HAL_PWREx_EnableUltraLowPower()", the systick (Using TIM2 as timebase) become slow. and if I disable ULP bit, systick will be back to normal.  

 

following is my power method, before enter STOP mode, I will call this method, and after wake-up from STOP, the HAL_getTick() will become very slow.

 

static void SystemPower_Config(void)
{
/* Enable Power Control clock */
__HAL_RCC_PWR_CLK_ENABLE();
/* Enable Ultra low power mode */
HAL_PWREx_EnableUltraLowPower();
HAL_PWREx_DisableFastWakeUp();
/* Select HSI as system clock source after Wake Up from Stop mode */
__HAL_RCC_WAKEUPSTOP_CLK_CONFIG (RCC_STOP_WAKEUPCLOCK_HSI);
}

 

Don't know the root-cause.

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