ADC Internal Temperature

vitthal muddapur · ‎2018-05-08

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 · ‎2018-05-10

Posted on May 10, 2018 at 17:32

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

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T J · ‎2018-05-10

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 · ‎2018-05-11

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 · ‎2018-05-11

Posted on May 11, 2018 at 07:51

what page in the reference manual are you on ?

vitthal muddapur · ‎2018-05-11

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 · ‎2018-05-11

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 the

ADC and Comparators. VREFINT is internally connected to the ADC_IN17 input channel. It

enables accurate monitoring of the VDD value (when no external voltage, VREF+, is available

for ADC). The precise voltage of VREFINT is individually measured for each part by ST during

production 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 address

VREFINT_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

.