STM32F030CC ADC reads 0

[Jpj.1]

Hi,

I am using stm32f030 to read adc value(truestudio). ADC reads value on an interval of 10 minutes. It is observer that ADC reads value for first 5-6 times,and after that it reads 0v.The readings we get is also different from what is measured on adcpin. what may be the issue??

static void MX_ADC_Init(void)

{

/* USER CODE BEGIN ADC_Init 0 */

/* USER CODE END ADC_Init 0 */

ADC_ChannelConfTypeDef sConfig = {0};

/* USER CODE BEGIN ADC_Init 1 */

/* USER CODE END ADC_Init 1 */

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

*/

hadc.Instance = ADC1;

hadc.Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV1;

hadc.Init.Resolution = ADC_RESOLUTION_12B;

hadc.Init.DataAlign = ADC_DATAALIGN_RIGHT;

hadc.Init.ScanConvMode = ADC_SCAN_DIRECTION_FORWARD;

hadc.Init.EOCSelection = ADC_EOC_SINGLE_CONV;

hadc.Init.LowPowerAutoWait = DISABLE;

hadc.Init.LowPowerAutoPowerOff = DISABLE;

hadc.Init.ContinuousConvMode = ENABLE;

hadc.Init.DiscontinuousConvMode = DISABLE;

hadc.Init.ExternalTrigConv = ADC_SOFTWARE_START;

hadc.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;

hadc.Init.DMAContinuousRequests = DISABLE;

hadc.Init.Overrun = ADC_OVR_DATA_PRESERVED;

if (HAL_ADC_Init(&hadc) != HAL_OK)

{

Error_Handler();

}

/** Configure for the selected ADC regular channel to be converted.

*/

sConfig.Channel = ADC_CHANNEL_8;

sConfig.Rank = ADC_RANK_CHANNEL_NUMBER;

sConfig.SamplingTime = ADC_SAMPLETIME_1CYCLE_5;

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

{

Error_Handler();

}

/* USER CODE BEGIN ADC_Init 2 */

/* USER CODE END ADC_Init 2 */

}

code for reading value:

while(1){

HAL_ADC_Start(&hadc);

HAL_ADC_PollForConversion(&hadc,100);

u16_adcVal = HAL_ADC_GetValue(&hadc);

HAL_ADC_Stop(&hadc);

}

[Vangelis Fortounas]

Hello

> sConfig.SamplingTime = ADC_SAMPLETIME_1CYCLE_5

Try to increase the sample time.

Regards

[Jpj.1]

Should I disable this or enable:

hadc.Init.ContinuousConvMode

Also sample time to ADC_SAMPLETIME_7CYCLES_5

Along with ADC I also use UART. A GSM module is connected to it. In an interval of 10 min, at 2 minute GSM is made off and at 8th minute GSM is turned on. ADC reads value on every 10th minute. it reads value for first 5 -6 cycle. after that it reads 0.

[Ozone]

A sample time of 1,5 cycle is very short, for sure.

But it is not a reasonable explanation for the observed effect.

I strongly suspect there is something wrong in your code processing sample date, and not the ADC.

You can try data breakpoints in your debugger - if it supports it.

I.e. a conditional BP at a location, if a variable matches a certain condition (like being 0).

[Jpj.1]

"I strongly suspect there is something wrong in your code processing sample date, and not the ADC." Sorry,I didnt get you

[Ozone]

You probably have a bug elsewhere.

The ADC value gets overwritten during processing.