ADC Internal Temperature

[vitthal muddapur]

Posted on May 08, 2018 at 13:18

Hi,

I am beginner in stm32 power supply 2.5v and Vdda 2.5

what is VDD_CALIB?

what is VDD_APPLI? 

[Amel NASRI]

Posted on May 10, 2018 at 17:32

https://community.st.com/0D50X00009nNBAiSAO

 

[T J]

Posted on May 11, 2018 at 00:54

this is my code for the 'F091

#define TEMP110_CAL_ADDR ((uint16_t*) ((uint32_t) 0x1FFFF7C2))  // calibrated at 3.3V +-10mV   @110C +/- 5C

#define TEMP30_CAL_ADDR ((uint16_t*) ((uint32_t) 0x1FFFF7B8))   // calibrated at 3.3V +-10mV   @ 30C +/- 5C #define VREFINT_CAL     ((uint16_t*) ((uint32_t) 0x1FFFF7BA))   // calibrated at 3.3V +-10mV   @ 30C +/- 5C #define VDD_CALIB ((uint16_t) (3300))#define VDD_APPLI ((uint16_t) (3295))

readtemp

    double processorTemp;                    // the temperature in degree Celsius

    int32_t AveTemperatureADC = ADC_Channel_AVE[VTemp_Ad16];     // 16x over sampled, needs /16

    processorTemp  =  (double) AveTemperatureADC / 16 - *TEMP30_CAL_ADDR;

    processorTemp *=  110 - 30;    processorTemp /=  ((double)*TEMP110_CAL_ADDR) - *TEMP30_CAL_ADDR;    processorTemp +=   30;    processorTemperature =  (int32_t)(processorTemp * 100);    //        sprintf(string,'AveTemperatureADC %04X, ADC_CalibrationFactor %04X, *TEMP30_CAL_ADDR %04X, processorTemperature %.2f, processorTemp %.3f \n\r',AveTemperatureADC,ADC_CalibrationFactor,(int32_t) *TEMP30_CAL_ADDR,((float)processorTemperature/100),processorTemp);    //        puts (string);

    Vdda = (double)16 * 3.3 * *VREFINT_CAL;

    Vdda /= ADC_Channel_AVE[VRef_Ad17];    this works much much better after a calibrate.  <- your next challenge.

I get approx 30C at start and 38-43C running endlessly.  usually 17C above ambient

   

[vitthal muddapur]

Posted on May 11, 2018 at 07:48

hi,

thank you for your response

I need information about 

VDD_APPLI and 

VDD_CALIB if vdd 2.5v

[T J]

Posted on May 11, 2018 at 07:51

what page in the reference manual are you on ?

[vitthal muddapur]

Posted on May 11, 2018 at 08:03

hi,

http://www.st.com/content/ccc/resource/technical/document/reference_manual/21/bd/0f/bd/1c/88/40/f0/DM00108282.pdf/files/DM00108282.pdf/jcr:content/translations/en.DM00108282.pdf

 

referance manual stm32l071 RM0377 page no.847 and A.8.17 Temperature computation code example 

not mention anywhere about 

VDD_APPLI and 

VDD_CALIB.

[T J]

Posted on May 11, 2018 at 08:44

You need to find the voltage applied when calibrated in the datasheet.

3.12.1 Internal voltage reference (VREFINT)

The internal voltage reference (VREFINT) provides a stable (bandgap) voltage output for theADC and Comparators. VREFINT is internally connected to the ADC_IN17 input channel. Itenables accurate monitoring of the VDD value (when no external voltage, VREF+, is availablefor ADC). The precise voltage of VREFINT is individually measured for each part by ST duringproduction test and stored in the system memory area. It is accessible in read-only mode.

Table 8. Internal voltage reference measured values

Calibration value name         Description                       Memory addressVREFINT_CAL                      Raw data acquired at                                              temperature of 25 °C        0x1FF8 0078 - 0x1FF8 0079                                              VDDA = 3 V 

that is 

VDD_CALIB

= 3V

your original question:

VDD_APPLI = 2.5V

.