How To read Multi Channel ADC on Blue Pill with continuous mode & Polling

[njtucza2]

I am using the STM32F103C8 (blue Pill) and have been having lots of troubles with reading multiple channels on ADC1. Here is my init code using firmware 1.7:

 ADC_ChannelConfTypeDef sConfig = {0};
 
 /* USER CODE BEGIN ADC1_Init 1 */
 
 /* USER CODE END ADC1_Init 1 */
 /**Common config 
 */
 hadc1.Instance = ADC1;
 hadc1.Init.ScanConvMode = ADC_SCAN_ENABLE;
 hadc1.Init.ContinuousConvMode = ENABLE;
 hadc1.Init.DiscontinuousConvMode = DISABLE;
 hadc1.Init.ExternalTrigConv = ADC_SOFTWARE_START;
 hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;
 hadc1.Init.NbrOfConversion = 4;
 if (HAL_ADC_Init(&hadc1) != HAL_OK)
 {
 Error_Handler();
 }
 /**Configure Regular Channel 
 */
 sConfig.Channel = ADC_CHANNEL_0;
 sConfig.Rank = ADC_REGULAR_RANK_1;
 sConfig.SamplingTime = ADC_SAMPLETIME_1CYCLE_5;
 if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
 {
 Error_Handler();
 }
 /**Configure Regular Channel 
 */
 sConfig.Channel = ADC_CHANNEL_1;
 sConfig.Rank = ADC_REGULAR_RANK_2;
 if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
 {
 Error_Handler();
 }
 /**Configure Regular Channel 
 */
 sConfig.Channel = ADC_CHANNEL_2;
 sConfig.Rank = ADC_REGULAR_RANK_3;
 if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
 {
 Error_Handler();
 }
 /**Configure Regular Channel 
 */
 sConfig.Channel = ADC_CHANNEL_3;
 sConfig.Rank = ADC_REGULAR_RANK_4;
 if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
 {
 Error_Handler();
 }

I am trying to read from analog pins PA0-3, and I am getting very odd results. Whenever I try change the value of just one ADC Pin, all of the values seem to change, and then on some pins when I change the value I see no response from the STM at all. Anyone have similar problems or see something up with my init? Here is how i call for values:

 HAL_ADC_Start(&hadc1);
 
 if(HAL_ADC_PollForConversion(&hadc1, 100) == HAL_OK);
 adc0 = HAL_ADC_GetValue(&hadc1);
 
 
 if(HAL_ADC_PollForConversion(&hadc1, 100) == HAL_OK)
 adc1 = HAL_ADC_GetValue(&hadc1);
 
 if(HAL_ADC_PollForConversion(&hadc1, 100) == HAL_OK);
 adc2 = HAL_ADC_GetValue(&hadc1);
 
 if(HAL_ADC_PollForConversion(&hadc1, 100) == HAL_OK);
 adc3 = HAL_ADC_GetValue(&hadc1);
 
 
 HAL_ADC_Stop(&hadc1);

[Rogers.Gary]

I know it will be little consolation, I tried multi-channel polling and gave up. I switched to DMA and getting pretty consistent results.

[MikeDB]

Well I program at a lower level but simply trigger the ADC on each channel in turn in my code and it works fine with little crosstalk

void start_ADC(uint8_t ADC_type)                        // start A-D convertors

   {

      ADC0_MUXPOS = ADC_type;

      ADC0_COMMAND = 0b00000001;                        

   }

         if (ADC0_INTFLAGS & 1)                        // should be ready - conversion takes 8.7uS

            Vadc1 = ADC0_RES;

[Rogers.Gary]

Soon as my two projects are done, going to get learning LL and register on the STM32L4 processors. Horrible HAL is too goofy :dizzy_face:

[MikeDB]

I tried it when it first came out and had to stop as too many problems. I keep telling myself I'll give it another try sometime but still haven't umpteen years later :)

[TDK]

You need to use DMA to read from multiple channels. Otherwise the ADC will only read from the channel on rank 1.

[Peter BENSCH]

This thread relates to a so-called Blue Pill, which uses illegally cloned STM32F103. ST resources are only dedicated to supporting genuine ST products. We are not committed to ensuring that clones/fakes products work properly with the firmware we provide.

We recommend to purchase genuine products from STMicroelectronics and purchase them from known and trusted distributors.

This thread will now be locked. However, if you face difficulties while using genuine ST products, we’re here to assist you. Please feel free to start a new thread, and our team, along with community members, will be ready to help you with any issues/questions you encounter.

Thank you for your understanding.

Regards
/Peter