stm32f765xx internal temperature sensor

[yjchoi0812]

Hello, I am currently trying to measure the temperature using the internal temperature sensor of STM32F765.

The Reference Manual stated to do temp = ((V_sense - V_25) / Avg_Slope) + 25,

but the address of calibration data existed in the Datasheet.

In this case, what formula should be used to measure temperature?

In my circuit, VDDA is connected to 3.3V, VREF+ is connected to 3.0V and ADC is set to 10bit resolution.

Additionally, I referred to RM0410 Reference Manual and STM32F765xx Datasheet.

[TDK]

You can either use the nominal values as given in the datasheet or you can use the calibrated values.

If you want to use calibrated values, see the function in the LL library:

/**
  * @brief  Helper macro to calculate the temperature (unit: degree Celsius)
  *         from ADC conversion data of internal temperature sensor.
  * @note   Computation is using temperature sensor calibration values
  *         stored in system memory for each device during production.
  * @note   Calculation formula:
  *           Temperature = ((TS_ADC_DATA - TS_CAL1)
  *                           * (TS_CAL2_TEMP - TS_CAL1_TEMP))
  *                         / (TS_CAL2 - TS_CAL1) + TS_CAL1_TEMP
  *           with TS_ADC_DATA = temperature sensor raw data measured by ADC
  *                Avg_Slope = (TS_CAL2 - TS_CAL1)
  *                            / (TS_CAL2_TEMP - TS_CAL1_TEMP)
  *                TS_CAL1   = equivalent TS_ADC_DATA at temperature
  *                            TEMP_DEGC_CAL1 (calibrated in factory)
  *                TS_CAL2   = equivalent TS_ADC_DATA at temperature
  *                            TEMP_DEGC_CAL2 (calibrated in factory)
  *         Caution: Calculation relevancy under reserve that calibration
  *                  parameters are correct (address and data).
  *                  To calculate temperature using temperature sensor
  *                  datasheet typical values (generic values less, therefore
  *                  less accurate than calibrated values),
  *                  use helper macro @ref __LL_ADC_CALC_TEMPERATURE_TYP_PARAMS().
  * @note   As calculation input, the analog reference voltage (Vref+) must be
  *         defined as it impacts the ADC LSB equivalent voltage.
  * @note   Analog reference voltage (Vref+) must be either known from
  *         user board environment or can be calculated using ADC measurement
  *         and ADC helper macro @ref __LL_ADC_CALC_VREFANALOG_VOLTAGE().
  * @note   On this STM32 series, calibration data of temperature sensor
  *         corresponds to a resolution of 12 bits,
  *         this is the recommended ADC resolution to convert voltage of
  *         temperature sensor.
  *         Otherwise, this macro performs the processing to scale
  *         ADC conversion data to 12 bits.
  * @PAram  __VREFANALOG_VOLTAGE__  Analog reference voltage (unit mV)
  * @PAram  __TEMPSENSOR_ADC_DATA__ ADC conversion data of internal
  *                                 temperature sensor (unit: digital value).
  * @PAram  __ADC_RESOLUTION__      ADC resolution at which internal temperature
  *                                 sensor voltage has been measured.
  *         This parameter can be one of the following values:
  *         @arg @ref LL_ADC_RESOLUTION_12B
  *         @arg @ref LL_ADC_RESOLUTION_10B
  *         @arg @ref LL_ADC_RESOLUTION_8B
  *         @arg @ref LL_ADC_RESOLUTION_6B
  * @retval Temperature (unit: degree Celsius)
  */
#define __LL_ADC_CALC_TEMPERATURE(__VREFANALOG_VOLTAGE__,\
                                  __TEMPSENSOR_ADC_DATA__,\
                                  __ADC_RESOLUTION__)                              \
  (((( ((int32_t)((__LL_ADC_CONVERT_DATA_RESOLUTION((__TEMPSENSOR_ADC_DATA__),     \
                                                    (__ADC_RESOLUTION__),          \
                                                    LL_ADC_RESOLUTION_12B)         \
                   * (__VREFANALOG_VOLTAGE__))                                     \
                  / TEMPSENSOR_CAL_VREFANALOG)                                     \
        - (int32_t) *TEMPSENSOR_CAL1_ADDR)                                         \
     ) * (int32_t)(TEMPSENSOR_CAL2_TEMP - TEMPSENSOR_CAL1_TEMP)                    \
    ) / (int32_t)((int32_t)*TEMPSENSOR_CAL2_ADDR - (int32_t)*TEMPSENSOR_CAL1_ADDR) \
   ) + TEMPSENSOR_CAL1_TEMP                                                        \
  )