ADC cannot read multiple channels ..

[Raider E]

Posted on December 16, 2016 at 00:08

The original post was too long to process during our migration. Please click on the attachment to read the original post.

[Seb]

Posted on December 16, 2016 at 01:00

How about using ADC Injected Channels? They have a Data Register per channel ==> no DMA needed ==> Simpler?

[Raider E]

Posted on December 16, 2016 at 01:07

Hi  Seb,

thank you for your reply, i am still in my early stages learning and not sure how the injected channels mode work. any example code for the multi channels using an injected channel mode I can start with? many thanks

[Seb]

Posted on December 16, 2016 at 04:01

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[Raider E]

Posted on December 16, 2016 at 01:04

Ok now I diabled DMA and wrote the following :

HAL_ADC_Start(&hadc1);

HAL_ADC_PollForConversion(&hadc1,1000);

value[0]= HAL_ADC_GetValue(&hadc1);

value[1]= HAL_ADC_GetValue(&hadc1);

HAL_ADC_Stop(&hadc1);

sConfig.Channel = ADC_CHANNEL_2;

sConfig.Rank = 2;

sConfig.SamplingTime = ADC_SAMPLETIME_3CYCLES;

if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)

{

Error_Handler();

}

sConfig.Channel = ADC_CHANNEL_0;

sConfig.Rank = 1;

if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)

{

Error_Handler();

}

and it reads two channels. However, it reads OK for few seconds and then the the values swap for a second and then come back, so value[0] becomes value[1] and vice versa and only happes for a second then its fine. Further why it reads 

ADC_CHANNEL_2 in value[0], I though the one with the lower rank number will be read first, is that correct?

[Raider E]

Posted on December 19, 2016 at 01:29

Hi again,

I am trying to use DMA now as its more straightforward but still not working for me. Ain[0 below is only reading some weired voltage .17 instead of 1.3V and Ain[1] reads nothing stays 0.  can you please have a look and let me know what might have gone wrong:

#include 'stm32f7xx_hal.h'

#include 'global.h'

#define NO_OF_CHANNELS 2

#define NO_OF_ADCs 1

//Note that Interrupts for all peripherals are located in the xxx_msp file and xxx_it

void MX_ADC1_Init(void);

void MX_DMA_Init(void);

void readAins(void);

void MX_DMA_Init(void)

{

/* DMA controller clock enable */

__HAL_RCC_DMA2_CLK_ENABLE();

/* DMA interrupt init */

/* DMA2_Stream0_IRQn interrupt configuration */

HAL_NVIC_SetPriority(DMA2_Stream0_IRQn, 0, 0);

HAL_NVIC_EnableIRQ(DMA2_Stream0_IRQn);

}

void MX_ADC1_Init(void)

{

ADC_ChannelConfTypeDef sConfig;

/**Configure the global features of the ADC (Clock, Resolution, Data Alignment and number of conversion)

*/

hadc1.Instance = ADC1;

hadc1.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV2;

hadc1.Init.Resolution = ADC_RESOLUTION_12B;

hadc1.Init.ScanConvMode = ENABLE;

hadc1.Init.ContinuousConvMode = DISABLE;

hadc1.Init.DiscontinuousConvMode = DISABLE;

hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;

hadc1.Init.ExternalTrigConv = ADC_SOFTWARE_START;

hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;

hadc1.Init.NbrOfConversion = 2;

hadc1.Init.DMAContinuousRequests = ENABLE;

hadc1.Init.EOCSelection = DISABLE;

HAL_ADC_Init(&hadc1);

// if (HAL_ADC_Init(&hadc1) != HAL_OK)

// {

// Error_Handler();

// }

/**Configure for the selected ADC regular channel its corresponding rank in the sequencer and its sample time.

*/

sConfig.Channel = ADC_CHANNEL_2;

sConfig.Rank = 2;

sConfig.SamplingTime = ADC_SAMPLETIME_3CYCLES;

HAL_ADC_ConfigChannel(&hadc1, &sConfig);

if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)

{

Error_Handler();

}

sConfig.Channel = ADC_CHANNEL_0;

sConfig.Rank = 1;

HAL_ADC_ConfigChannel(&hadc1, &sConfig);

if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)

{

Error_Handler();

}

// All Channels has to be preconfgured here as above

}

void readAins(void){

HAL_ADC_Start_DMA(&hadc1, (uint32_t*)&value2, 2);

Ain[0]=value2[0];

Ain[1]=value2[1];

}

msp file:

void HAL_ADC_MspInit(ADC_HandleTypeDef* hadc)

{

GPIO_InitTypeDef GPIO_InitStruct;

if(hadc->Instance==ADC1)

{

/* USER CODE BEGIN ADC1_MspInit 0 */

/* USER CODE END ADC1_MspInit 0 */

/* Peripheral clock enable */

__HAL_RCC_ADC1_CLK_ENABLE();

/**ADC1 GPIO Configuration

PA0/WKUP ------> ADC1_IN0

PA1 ------> ADC1_IN1

*/

GPIO_InitStruct.Pin = GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_2;

GPIO_InitStruct.Mode = GPIO_MODE_ANALOG;

GPIO_InitStruct.Pull = GPIO_NOPULL;

HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

/* USER CODE BEGIN ADC1_MspInit 1 */

/* USER CODE END ADC1_MspInit 1 */

/* Peripheral DMA init*/

hdma_adc1.Instance = DMA2_Stream0;

hdma_adc1.Init.Channel = DMA_CHANNEL_0;

hdma_adc1.Init.Direction = DMA_PERIPH_TO_MEMORY;

hdma_adc1.Init.PeriphInc = DMA_PINC_DISABLE;

hdma_adc1.Init.MemInc = DMA_MINC_ENABLE;

hdma_adc1.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD;

hdma_adc1.Init.MemDataAlignment = DMA_MDATAALIGN_WORD;

hdma_adc1.Init.Mode = DMA_CIRCULAR;

hdma_adc1.Init.Priority = DMA_PRIORITY_HIGH;

hdma_adc1.Init.FIFOMode = DMA_FIFOMODE_DISABLE;

hdma_adc1.Init.FIFOThreshold = DMA_FIFO_THRESHOLD_HALFFULL;

hdma_adc1.Init.MemBurst = DMA_MBURST_SINGLE;

hdma_adc1.Init.PeriphBurst = DMA_PBURST_SINGLE;

HAL_DMA_Init(&hdma_adc1);

// if (HAL_DMA_Init(&hdma_adc1) != HAL_OK)

// {

// Error_Handler();

// }

__HAL_LINKDMA(hadc,DMA_Handle,hdma_adc1);

}

}

void HAL_ADC_MspDeInit(ADC_HandleTypeDef* hadc)

{

if(hadc->Instance==ADC1)

{

/* USER CODE BEGIN ADC1_MspDeInit 0 */

/* USER CODE END ADC1_MspDeInit 0 */

/* Peripheral clock disable */

__HAL_RCC_ADC1_CLK_DISABLE();

/**ADC1 GPIO Configuration

PA0/WKUP ------> ADC1_IN0

PA1 ------> ADC1_IN1

*/

HAL_GPIO_DeInit(GPIOA, GPIO_PIN_0|GPIO_PIN_1);

/* Peripheral DMA DeInit*/

HAL_DMA_DeInit(hadc->DMA_Handle);

// __HAL_LINKDMA(hadc,DMA_Handle,hdma_adc1);

}

/* USER CODE BEGIN ADC1_MspDeInit 1 */

/* USER CODE END ADC1_MspDeInit 1 */

}

[T J]

Posted on January 22, 2017 at 08:10

Hi, did you get it working ?