Internal Temperature STM32H7 delivers wrong value

[Roni]

I read the messages in here about wrong temperature values including code examples, but still getting wrong values:

I need to measure the internal CPU temperature sensor from the STM32H743XIH6. I activated the ADC3 using STM32CUBEMX (V. 6.9.2) and selected Temperature Channel.

However the calculated temperatures are far too high (140-170):

ADC input clock is set to 37.5 MHz

read T1_30 - address: 0x1FF1E820 - getting value: 0x3064

T1_110 - address: 0x1FF1E840 - getting value: 0x4023

reading GetValue - HAL_ADC_GetValue: 0x4783, 0x4a04, 0x4c68

it is grater than T1_110, how come?!

Mpu internal Temperature: GetValue=0x4783, T1_110=0x4023, T1_30=0x3064
Mpu internal Temperature: 147.47

Mpu internal Temperature: GetValue=0x4a04, T1_110=0x4023, T1_30=0x3064
Mpu internal Temperature: 160.19

Mpu internal Temperature: GetValue=0x4c68, T1_110=0x4023, T1_30=0x3064
Mpu internal Temperature: 172.34

see code below

Any help is very much appreciated!

thanks in advanced

static void MX_ADC3_Init(void)

{

  /* USER CODE BEGIN ADC3_Init 0 */

  /* USER CODE END ADC3_Init 0 */

  ADC_ChannelConfTypeDef sConfig = {0};

  /* USER CODE BEGIN ADC3_Init 1 */

  /* USER CODE END ADC3_Init 1 */

  /** Common config

  */

  hadc3.Instance = ADC3;

  hadc3.Init.Resolution = ADC_RESOLUTION_16B;

  hadc3.Init.ScanConvMode = ADC_SCAN_DISABLE;

  hadc3.Init.EOCSelection = ADC_EOC_SINGLE_CONV;

  hadc3.Init.LowPowerAutoWait = DISABLE;

  hadc3.Init.ContinuousConvMode = DISABLE;

  hadc3.Init.NbrOfConversion = 1;

  hadc3.Init.DiscontinuousConvMode = DISABLE;

  hadc3.Init.NbrOfDiscConversion = 1;

  hadc3.Init.ExternalTrigConv = ADC_SOFTWARE_START;

  hadc3.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;

  hadc3.Init.ConversionDataManagement = ADC_CONVERSIONDATA_DR;

  hadc3.Init.Overrun = ADC_OVR_DATA_OVERWRITTEN;

  hadc3.Init.LeftBitShift = ADC_LEFTBITSHIFT_NONE;

  hadc3.Init.OversamplingMode = ENABLE;

  hadc3.Init.Oversampling.Ratio = 256;

  hadc3.Init.Oversampling.RightBitShift = ADC_RIGHTBITSHIFT_4;

  hadc3.Init.Oversampling.TriggeredMode = ADC_TRIGGEREDMODE_SINGLE_TRIGGER;

  hadc3.Init.Oversampling.OversamplingStopReset = ADC_REGOVERSAMPLING_CONTINUED_MODE;

  if (HAL_ADC_Init(&hadc3) != HAL_OK)

  {

    Error_Handler();

  }

  /** Configure Regular Channel

  */

  sConfig.Channel = ADC_CHANNEL_TEMPSENSOR;

  sConfig.Rank = ADC_REGULAR_RANK_1;

  sConfig.SamplingTime = ADC_SAMPLETIME_387CYCLES_5;

  sConfig.SingleDiff = ADC_SINGLE_ENDED;

  sConfig.OffsetNumber = ADC_OFFSET_NONE;

  sConfig.Offset = 0;

  sConfig.OffsetSignedSaturation = DISABLE;

  if (HAL_ADC_ConfigChannel(&hadc3, &sConfig) != HAL_OK)

  {

    Error_Handler();

  }

  /* USER CODE BEGIN ADC3_Init 2 */

  /* USER CODE END ADC3_Init 2 */

}

uint16_t ReadSingleA2D(void)

{

ADC_ChannelConfTypeDef sConfig;

HAL_StatusTypeDef err;

ADC_HandleTypeDef *hadc;

hadc = &hadc3;

/** Configure Regular Channel

*/

sConfig.Channel = ADC_CHANNEL_TEMPSENSOR;

sConfig.Rank = ADC_REGULAR_RANK_1;

sConfig.SamplingTime = ADC_SAMPLETIME_387CYCLES_5;

sConfig.SingleDiff = ADC_SINGLE_ENDED;

sConfig.OffsetNumber = ADC_OFFSET_NONE;

sConfig.Offset = 0;

sConfig.OffsetSignedSaturation = DISABLE;

// The ADC Boost mode can be controlled through the BOOST bit in the ADC_CR register.

// This bit must be set according to the ADC clock setting. Refer to the ADC_CR register description.

LL_ADC_SetBoostMode(hadc->Instance, LL_ADC_BOOST_MODE_50MHZ);

if((err=HAL_ADCEx_Calibration_Start(hadc, ADC_CALIB_OFFSET, ADC_SINGLE_ENDED)) != HAL_OK)

{

ErrorHandler(__FUNCTION__, __LINE__, (char *)"ADC Calibration error=%d", err);

}

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

{

ErrorHandler(__FUNCTION__, __LINE__, (char *)"ADC Config Channel error=%d", err);

}

if ((err=HAL_ADC_Start(hadc)) != HAL_OK)

{

ErrorHandler(__FUNCTION__, __LINE__, (char *)"ADC Start error=%d", err);

}

// wait for the end of conversion

if ((err=HAL_ADC_PollForConversion(hadc, 100)) != HAL_OK)

{

ErrorHandler(__FUNCTION__, __LINE__, (char *)"ADC end of Conversion error=%d", err);

}

return HAL_ADC_GetValue(hadc);

}

void GetMPUTemperature(void)

{

double CelsiusTemperature = 0.0;

uint32_t GetValue = 0;

// read the calibation values

uint32_t T1_30 = (uint32_t) *TEMPSENSOR_CAL1_ADDR;

uint32_t T1_110 = (uint32_t) *TEMPSENSOR_CAL2_ADDR;

// read the temperature

GetValue = ReadSingleA2D(MPU_INTERNAL_TEMPERATURE);

//calculate the temperature in (in °C)

// Analog-to-digital converters (ADC)

// Temperature (in °C) = ((110 °C – 30 °C)/(TS_CAL2 – TS_CAL1))× (TS_DATA – TS_CAL1) + 30 °C

CelsiusTemperature = ( (((double)(110 - 30))/((double)(T1_110 - T1_30))) * ((double)(GetValue - T1_30)) ) + ((double)30);

ErrorHandler(__FUNCTION__, __LINE__,(char *) "Mpu internal Temperature: GetValue=0x%x, T1_110=0x%x, T1_30=0x%x", GetValue, T1_110, T1_30);

ErrorHandler(__FUNCTION__, __LINE__,(char *) "Mpu internal Temperature: %.2f", CelsiusTemperature);

}

[liaifat85]

You can Use HAL_ADC_GetState to check the ADC state during different stages of your code execution. This can help identify where the issue might be occurring.

[Roni]

it seems the state is 0x0201 all the time:

#define HAL_ADC_STATE_REG_EOC           (0x00000200UL)   /*!< Conversion data available on group regular */

#define HAL_ADC_STATE_READY             (0x00000001UL)   /*!< ADC peripheral ready for use */

but the case after I call HAL_ADC_Start:

the state is 0x0100:

#define HAL_ADC_STATE_REG_BUSY          (0x00000100UL)   /*!< A conversion on ADC group regular is ongoing or can occur (either by continuous mode, external trigger, low power auto power-on (if feature available), multimode ADC master control (if feature available)) */

looks O.K

[TDK]

What board is this? What is VREF+ on your board?

[David Littell]

The TS_CAL2 values are different between rev Y and rev V devices.  See the Data Sheet Sections 6 and 7.

[Roni]

I disabled the OversamplingMode and now reading GetValue - HAL_ADC_GetValue: 0x351a, 3527

which is Mpu internal Temperature: 53-54 degrees

is this make sense?

[KDJEM.1]

Hi @Roni and welcome to the community 🙂,

For the Oversampling Mode issue, this is a known issue, already reported in STM32H723 ADC Oversampling code generation bug - STMicroelectronics Community.

This code line in generation code is wrong: 

  hadc3.Init.Oversampling.Ratio = 256;

  and should be 

hadc3.Init.Oversampling.Ratio = ADC3_OVERSAMPLING_RATIO_256;

Internal ticket number: 176763 (This is an internal tracking number and is not accessible or usable by customers).

Thank you.

Kaouthar