ADC returns wrong value

[oziesin]

I have a hardware that have on stm32g071 chip and mcp9700 temperature sensor. I tried reading temperature and i read 2040.(ADC 12bit resolution).

I also measured directly on hardware using multimeter and i read about 0.7 V So ADC measures wrong. 

Addition:

I read temperature using nucleo board that have on g0 series microprocessor. Is it about hardware ? Any suggestion would be appriciate.

[oziesin]

I did not any connection Vref+ pin , is it must ? I' ve read Vrefint and i calculate calibration formula then i read that value about 1.4 V but datasheet says it must be between 1.182 V to 1.232 V.

[TDK]

> I did not any connection Vref+ pin , is it must ? 

Yes. Details are in the datasheet, generally it must be tied to VDDA. What do you think you're using as a voltage reference then?

VREFINT can not be used as a voltage reference directly. It's simply a voltage within the mcu you can use to approximate what VREF+ is.

[oziesin · Accepted solution]

Thank you very much. When I cabled vref+ and vdda it is correctly working.