Associate II

Question

STM32L452 temperature sensor

I'm using the below to calculate the temperature in STM32L452 CPU:

int16_t temperatureC ;

// ADC VREF is external 3V3

temperature = __HAL_ADC_CALC_TEMPERATURE (3300, ADC_val, ADC_RESOLUTION_12B);

For ADC_val = 1360 - then temperatureC is 164 Celsius, which is surely not the right temperature.

Did anyone do better?

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Super User

What value do you get when you convert the internal voltage reference?

Is this a "known good" board such as Nucleo or Disco, or your own?

JW

The temperature sensor has a minimum sample time requirement. Make sure you are meeting it.

If that's not it, maybe read the values in TEMPSENSOR_CAL1_ADDR / TEMPSENSOR_CAL2_ADDR directly to verify they are consistent with your measurement.

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Principal

Damn there is a temp question each week! It deserves to become an ADC advertised example....

There are several L4 examples that use the temperature sensor. Here is one:

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IP.2Author

Associate II

Thanks to all responders, every answer helped to locate the missing bit which was this:

LL_ADC_SetCommonPathInternalCh(__LL_ADC_COMMON_INSTANCE(ADC1), ADC_CCR_TSEN | ADC_CCR_VREFEN | ADC_CCR_VBATEN );

I still get 41C at room temperature, which seems higher than expected.

For waclawek.jan : Vref is 1V210, within range.

It’s measuring the junction temperature, which is going to be significantly higher than ambient. 41 C seems reasonable for typical clock speeds.

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