Is it needed to start ADC_DMA again after waking up from Stop mode?

[duybienle]

Posted on July 21, 2016 at 10:36 Hi, I want to read a single conversion of multiple channels of an ADC repeatedly, after searching I found the solution that is using ADC_DMA. Since in my porject I need to put the uC into Stop mode after a single conversion of ADC and wait until the next conversion (trigger by LPTIM), however I don't know if I need to start the ADC_DMA again after waking up from Stop mode ? A simple code to demonstrate the situation is as follow:

int

main( void ) { HAL_Init(); MX_GPIO_Init(); MX_ADC_Init(); MX_TIM2_Init(); if (HAL_ADCEx_Calibration_Start(&hadc, ADC_SINGLE_ENDED) != HAL_OK) Error_Handler(); } /* Start ADC conversion with transfer by DMA */ if (HAL_ADC_Start_DMA(&hadc, (uint32_t *)ADC_DMA_val, nbrADCchannel) != HAL_OK) Error_Handler(); } while (1) { // Is it needed to start DMA again ??????????? // HAL_ADC_Start_DMA(&hadc, (uint32_t *)ADC_DMA_val, nbrADCchannel) HAL_ADC_Start(&hadc); HAL_PWR_EnterSTOPMode(PWR_LOWPOWERREGULATOR_ON, PWR_STOPENTRY_WFI); } } void HAL_ADC_ConvCpltCallback(ADC_HandleTypeDef *hadc) { /* Read captured ADC values */ } Thanks, Bien

[Walid FTITI_O]

Posted on July 21, 2016 at 14:16

Hi  le.bien,

In stop mode, all peripheral clocks are gated. To make your application operate correctly, on entering stop mode , disable ADC then DMA. On return enable DMA then ADC. Note, that if your system clock is different from HSI setting , you out to reconfigure it after exiting the stop mode. -Hannibal-

[duybienle]

Posted on July 21, 2016 at 16:03

Hi Hannibal

Thanks, your info helps me alot. Just to make sure I understand correctly: - On entering Stop mode:

 HAL_ADC_Stop --> HAL_ADC_Stop_DMA

- On returning from Stop mode:

 HAL_ADC_Start_DMA --> HAL_ADC_Start

And I also have to do the same thing for e.g Timers and other modules right ? Thanks again Bien