ADC: stuck inside HAL_ADC_GetValue()

[Sam4]

Hello there,

I have created my own project following the preconfigured project "ADC_RegularConversion_Interrupt". In my project I want to get the internal temperature sensor value and want to display it on the terminal thus using the UART example in this project as well.

However, I stuck forever inside HAL_ADC_GetValue() function. I am aware about the fact the priority of adc needs to be >= 1 (since only systick can have the highest priority => 0).

see adc config below with read temperature function:

static void init_adc(void)
{
	adc_handle.Instance = ADCx;
	if(HAL_ADC_DeInit(&adc_handle) != HAL_OK)
	{
		Error_Handler();
	}
	adc_handle.Init.ClockPrescaler        = ADC_CLOCKPRESCALER_PCLK_DIV4;
	adc_handle.Init.Resolution            = ADC_RESOLUTION_12B;
	adc_handle.Init.ScanConvMode          = DISABLE;                       /* Sequencer disabled (ADC conversion on only 1 channel: channel set on rank 1) */
	adc_handle.Init.ContinuousConvMode    = ENABLE;                       /* Continuous mode enabled to have continuous conversion  */
	adc_handle.Init.DiscontinuousConvMode = DISABLE;                       /* Parameter discarded because sequencer is disabled */
	adc_handle.Init.NbrOfDiscConversion   = 0;
	adc_handle.Init.ExternalTrigConvEdge  = ADC_EXTERNALTRIGCONVEDGE_NONE;        /* Conversion start triggered at each external event */
	adc_handle.Init.ExternalTrigConv      = ADC_EXTERNALTRIGCONV_T1_CC1;
	adc_handle.Init.DataAlign             = ADC_DATAALIGN_RIGHT;
	adc_handle.Init.NbrOfConversion       = 1;
	adc_handle.Init.DMAContinuousRequests = DISABLE;
	adc_handle.Init.EOCSelection          = DISABLE;

	if(HAL_ADC_Init(&adc_handle) != HAL_OK)
	{
		Error_Handler();
	}

}

static void init_adc_channel(void)
{
	adc_channel_conf.Channel = ADC_CHANNEL_TEMPSENSOR;
	adc_channel_conf.Rank = 1;
	adc_channel_conf.SamplingTime = ADC_SAMPLETIME_15CYCLES;
	adc_channel_conf.Offset = 0;

	if(HAL_ADC_ConfigChannel(&adc_handle, &adc_channel_conf) != HAL_OK)
	{
		Error_Handler();
	}

	//start the conversion process
	if(HAL_ADC_Start_IT(&adc_handle) != HAL_OK)
	{
		Error_Handler();
	}
}

float read_temperature(ADC_HandleTypeDef *adc_handle)
{
	adc_val = HAL_ADC_GetValue(adc_handle);

	float Vref = 3.3;
	float Vsense = (adc_val * Vref) / 4095.0; //for 12bit resolution 2^12 = 0 <-> 4095
	float avg_slope = 0.0025; //2.5 mV/C = 0.0025 V/C
	float V25 = 0.76;

	float temp_celcius = ((Vsense - V25) / avg_slope) + 25.0;

	return temp_celcius;
}

see below ADC MSP config:

void HAL_ADC_MspInit(ADC_HandleTypeDef *hadc)
{
  GPIO_InitTypeDef          GPIO_InitStruct;

  /*##-1- Enable peripherals and GPIO Clocks #################################*/
  /* ADC Periph clock enable */
  ADCx_CLK_ENABLE();
  /* Enable GPIO clock ****************************************/
  ADCx_CHANNEL_GPIO_CLK_ENABLE();

  /*##-2- Configure peripheral GPIO ##########################################*/
  /* ADC Channel GPIO pin configuration */
  GPIO_InitStruct.Pin = ADCx_CHANNEL_PIN;
  GPIO_InitStruct.Mode = GPIO_MODE_ANALOG;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(ADCx_CHANNEL_GPIO_PORT, &GPIO_InitStruct);

  /*##-3- Configure the NVIC #################################################*/
  /* NVIC configuration for ADC interrupt */
  HAL_NVIC_SetPriority(ADCx_IRQn, 1, 1);
  HAL_NVIC_EnableIRQ(ADCx_IRQn);
}

/**
  * @brief ADC MSP De-Initialization
  *        This function frees the hardware resources used in this example:
  *          - Disable the Peripheral's clock
  *          - Revert GPIO to their default state
  * @PAram hadc: ADC handle pointer
  * @retval None
  */
void HAL_ADC_MspDeInit(ADC_HandleTypeDef *hadc)
{

  /*##-1- Reset peripherals ##################################################*/
  ADCx_FORCE_RESET();
  ADCx_RELEASE_RESET();

  /*##-2- Disable peripherals and GPIO Clocks ################################*/
  /* De-initialize the ADC Channel GPIO pin */
  HAL_GPIO_DeInit(ADCx_CHANNEL_GPIO_PORT, ADCx_CHANNEL_PIN);
}

Thanks,

[Andrew Neil]

So have you stepped into the HAL_ADC_GetValue() function to see where, exactly, it's getting stuck, and what it's waiting for?

[Sam4]

all what it does in this function to fetch the value from data register

return hadc->Instance->DR;

thanks,

[Sam4 · Accepted solution]

Actually, I got it working.

Since I am still getting the gist of my new stm32f767, I did not have an adc interrupt callback set up in "stm32f7xx_it.c" file, thats why it was not getting any value from HAL_ADC_GetValue().

Thanks,