VDDA and PA2 ADC measurements

[Jérémy Da Silva]

Posted on August 30, 2017 at 15:48

Hello,

I work on a STM32L151CCU6 and I need your help.

I try to measure VDDA voltage in order to calculate a voltage divider on PA2 (single mode). My two ADC configuration functions are :

void MX_ADC_Init(void)

{  GPIO_InitTypeDef gpioInit1;  GPIO_InitTypeDef gpioInit2;       gpioInit1.Pin = PID_PIN; //PA2    gpioInit1.Mode = GPIO_MODE_ANALOG;    gpioInit1.Pull = GPIO_NOPULL;    HAL_GPIO_Init(PID_PORT, &gpioInit1); PA2        gpioInit2.Pin = PID_POWER_SUPPLY_PIN; //PB2    gpioInit2.Mode = GPIO_MODE_OUTPUT_PP;    gpioInit2.Pull = GPIO_NOPULL;    HAL_GPIO_Init(PID_POWER_SUPPLY_PORT, &gpioInit2); //PB2      __HAL_RCC_ADC1_CLK_ENABLE();  ADC_ChannelConfTypeDef sConfig;

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

    */  adc_identification.Instance = ADC1;  adc_identification.Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV2;  adc_identification.Init.Resolution = ADC_RESOLUTION_12B;  adc_identification.Init.DataAlign = ADC_DATAALIGN_RIGHT;  adc_identification.Init.ScanConvMode = ADC_SCAN_DISABLE;  adc_identification.Init.EOCSelection = ADC_EOC_SEQ_CONV;  adc_identification.Init.LowPowerAutoWait = ADC_AUTOWAIT_DISABLE;  adc_identification.Init.LowPowerAutoPowerOff = ADC_AUTOPOWEROFF_DISABLE;  adc_identification.Init.ChannelsBank = ADC_CHANNELS_BANK_A;  adc_identification.Init.ContinuousConvMode = DISABLE;  adc_identification.Init.NbrOfConversion = 1;  adc_identification.Init.DiscontinuousConvMode = DISABLE;  adc_identification.Init.ExternalTrigConv = ADC_SOFTWARE_START;  adc_identification.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;  adc_identification.Init.DMAContinuousRequests = DISABLE;  if (HAL_ADC_Init(&adc_identification) != HAL_OK)  {    while(1);  }

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

    */  sConfig.Channel = ADC_CHANNEL_2;  sConfig.Rank = 1;  sConfig.SamplingTime = ADC_SAMPLETIME_384CYCLES;  if (HAL_ADC_ConfigChannel(&adc_identification, &sConfig) != HAL_OK)  {    while(1);  }  ADC_Enable(&adc_identification);}

and :

void MX_ADC_VDD_Init(void)

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

  VDD_measurement.Instance = ADC1;

  VDD_measurement.Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV1;  VDD_measurement.Init.Resolution = ADC_RESOLUTION_12B;  VDD_measurement.Init.DataAlign = ADC_DATAALIGN_RIGHT;  VDD_measurement.Init.ScanConvMode = ADC_SCAN_DISABLE;  VDD_measurement.Init.EOCSelection = ADC_EOC_SEQ_CONV;  VDD_measurement.Init.LowPowerAutoWait = ADC_AUTOWAIT_DISABLE;  VDD_measurement.Init.LowPowerAutoPowerOff = ADC_AUTOPOWEROFF_DISABLE;  VDD_measurement.Init.ChannelsBank = ADC_CHANNELS_BANK_A;  VDD_measurement.Init.ContinuousConvMode = DISABLE;  VDD_measurement.Init.NbrOfConversion = 1;  VDD_measurement.Init.DiscontinuousConvMode = DISABLE;  VDD_measurement.Init.ExternalTrigConv = ADC_SOFTWARE_START;  VDD_measurement.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;  VDD_measurement.Init.DMAContinuousRequests = DISABLE;  if (HAL_ADC_Init(&VDD_measurement) != HAL_OK)  {    while(1);  }

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

    */  sConfig.Channel = ADC_CHANNEL_17;  sConfig.Rank = 1;  sConfig.SamplingTime = ADC_SAMPLETIME_4CYCLES;  if (HAL_ADC_ConfigChannel(&VDD_measurement, &sConfig) != HAL_OK)  {    while(1);  }  ADC_Enable(&VDD_measurement);}

When I try to measure this two ADC channel, I find 0.

I use this function : HAL_ADC_GetValue(&VDD_measurement);

Does anyone know where is my problem?

Thanks,

Jérémy

[Vangelis Fortounas]

Posted on August 30, 2017 at 20:45

Hello!

>>> I use this function : HAL_ADC_GetValue(&VDD_measurement);

This function gets converted value only.

Also your ADC_SAMPLETIME_4CYCLES is small.  My suggestion is to increase it at least to ADC_SAMPLETIME_96CYCLES  and after you have a success reading try to calculate the exact timing.

Try to use

uint32_t vdda;

#define VREFINT_CAL_ADDR ((uint16_t*) (0x1FF800F8U)) /* Internal voltage reference,

#define VREFINT_CAL_VREF                   ( 3000U)                    /* Analog voltage reference

HAL_ADC_Start(&VDD_measurement);

vdda=VREFINT_CAL_VREF*(*VREFINT_CAL_ADDR);//VDDA = 3 V x VREFINT_CAL / VREFINT_DATA

HAL_ADC_PollForConversion(&VDD_measurement, 1000);

vdda /=HAL_ADC_GetValue(&VDD_measurement);

The vdda value will be in millivolts.

Use the same way to read the PA2  Start, Wait, Read.

Regards

vf

[Jérémy Da Silva]

Posted on August 31, 2017 at 10:42

Hello!

Thank you ! That is working well for VDDA but not for PA2.

I have changed the Init function like below:

void MX_ADC_Init(void)

{  GPIO_InitTypeDef gpioInit1;  GPIO_InitTypeDef gpioInit2;       gpioInit1.Pin = PID_PIN;  //PA2    gpioInit1.Mode = GPIO_MODE_ANALOG;    gpioInit1.Pull = GPIO_NOPULL;    HAL_GPIO_Init(PID_PORT, &gpioInit1);        gpioInit2.Pin = PID_POWER_SUPPLY_PIN;  //PB2    gpioInit2.Mode = GPIO_MODE_OUTPUT_PP;    gpioInit2.Pull = GPIO_NOPULL;    HAL_GPIO_Init(PID_POWER_SUPPLY_PORT, &gpioInit2);      __HAL_RCC_ADC1_CLK_ENABLE();  ADC_ChannelConfTypeDef sConfig;

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

    */  adc_identification.Instance = ADC1;  adc_identification.Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV1;  adc_identification.Init.Resolution = ADC_RESOLUTION_12B;  adc_identification.Init.DataAlign = ADC_DATAALIGN_RIGHT;  adc_identification.Init.ScanConvMode = ADC_SCAN_DISABLE;  adc_identification.Init.EOCSelection = ADC_EOC_SEQ_CONV;  adc_identification.Init.LowPowerAutoWait = ADC_AUTOWAIT_UNTIL_DATA_READ;  adc_identification.Init.LowPowerAutoPowerOff = ADC_AUTOPOWEROFF_DISABLE;  adc_identification.Init.ChannelsBank = ADC_CHANNELS_BANK_A;  adc_identification.Init.ContinuousConvMode = DISABLE;  adc_identification.Init.NbrOfConversion = 1;  adc_identification.Init.DiscontinuousConvMode = DISABLE;  adc_identification.Init.ExternalTrigConv = ADC_SOFTWARE_START;  adc_identification.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;  adc_identification.Init.DMAContinuousRequests = DISABLE;  if (HAL_ADC_Init(&adc_identification) != HAL_OK)  {    while(1);  }

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

    */  sConfig.Channel = ADC_CHANNEL_2;  sConfig.Rank = 1;  sConfig.SamplingTime = ADC_SAMPLETIME_96CYCLES;  if (HAL_ADC_ConfigChannel(&adc_identification, &sConfig) != HAL_OK)  {    while(1);  }  ADC_Enable(&adc_identification);}

And I read the value of the voltage like :

void ADC_Measure(ADC_HandleTypeDef* hadc)

{        MX_ADC_Init(); //Init ADC        ADC_PowerOnPin(); //Enable the 3.3V of the voltage divider        ADC_Start(hadc);         HAL_ADC_PollForConversion(hadc, 1000);        ADC_Measure_ID =HAL_ADC_GetValue(hadc);        ADC_PowerOffPin(); //Disable the 3.3V of the voltage divider        ADC_Stop(hadc);}

But I receive 0. I use exactly the same parameters in initialization as for VDD and the same measurement function too.

Any idea for this point?

Thank you for your help.

[Jérémy Da Silva]

Posted on September 04, 2017 at 10:22

Hello,

Any ideas?

Thank you.

[Vangelis Fortounas]

Posted on September 04, 2017 at 17:11

Hi

in GPIO initialization function the GPIO clock seems not enabled.

__HAL_RCC_GPIOX_CLK_ENABLE();