ADC getvalue() not giving values

[RWagh.2]

Hello,

I am using STM32L011G4U7 and wants to get the adc value where it showed once and not it is giving 0 for the adc raw values. Also please let me know that in order to read the vcc that is 3.3 volts do I need to select VREFINT channel as well along with ADC pin?

Here's my code:

 void ReadVCC(byte ATR[])

 {

 HAL_ADC_Start_IT(&hadc);

 HAL_ADC_PollForConversion(&hadc, HAL_MAX_DELAY);

 adcval = HAL_ADC_GetValue(&hadc);

 HAL_Delay(1);

 VDDA = VREF * (VREFINT_CAL / adcval);

 ATR[6] = (uint8_t) (VDDA>>8); // MSB

 ATR[7] = (uint8_t) (VDDA & 0x00FF); // LSB

  }

result: adcval 0

VDDA 1

[AJOY.1]

For open adc channel, it will give garbage value between vcc and gnd.

Once the channel is connected with any voltage, it should give corresponding voltage value.

[RWagh.2]

My adc pin is connected to voltage divider and it is giving 1024 raw value

[ONadr.1]

I cant see channel configuration in this code. (HAL_ADC_ConfigChannel(.....) )

[TDK · Accepted solution]

Look at an example for the proper usage of HAL_ADC commands.

Here is one of many:

https://github.com/STMicroelectronics/STM32CubeL0/blob/a7b74aed35ecb7baeadeb16107aa8fddb6823589/Projects/STM32L073Z-EVAL/Examples/ADC/ADC_RegularConversion_Polling/Src/main.c

[S.Ma]

Vdda is usually vdd. Vref is a bandgap fixed voltage as internal channel. Reading it makes vdd deductable. When vdd is lowered, vref converted value goes up, and reversibly.