Hello, I am trying to read battery voltage within a task called by sequencer on STM32WB55CEU.
I am following this post: https://community.st.com/t5/stm32-mcus/how-to-use-the-stm32-adc-s-internal-reference-voltage/ta-p/621425
I verified that I can measure both VREFint and Channel 10 separately in Single Mode, however combining 2 measurements in Scan mode does not work. I am not sure whats causing this, considering I am doing everything as recommended in the provided post. It may not be related to BLE. I must be missing something obvious.
In the following code, the call to
/*
* Rank 2: measurement channel
*/
stat = HAL_ADC_PollForConversion(&hadc1, 0xffff);
uint32_t measurement_raw = HAL_ADC_GetValue(&hadc1);
takes about 10 seconds and measurement_raw becomes same value as vrefint_raw. The Vrefint conversion seems ok.
This is the whole code:
void ADC_BattMonitor_Init(void) {
HAL_ADCEx_Calibration_Start(&hadc1, ADC_SINGLE_ENDED);
__NOP();
}
float ADC_BattMonitor_GetVoltage(void) {
HAL_StatusTypeDef stat;
stat = HAL_ADC_Start(&hadc1);
/*
* Rank 1: vref internal
*/
stat = HAL_ADC_PollForConversion(&hadc1, 0xffff);
uint32_t vrefint_raw = HAL_ADC_GetValue(&hadc1);
/*
* Rank 2: measurement channel
*/
stat = HAL_ADC_PollForConversion(&hadc1, 0xffff);
uint32_t measurement_raw = HAL_ADC_GetValue(&hadc1);
/*
* This macro calculates the vdda voltage (as a uint32_t representing the voltage in milliVolts)
* using the vref internal raw adc value, and the internal calibration value in ROM
*/
uint32_t vdda_voltage = __HAL_ADC_CALC_VREFANALOG_VOLTAGE(vrefint_raw, ADC_RESOLUTION_12B);
/*
* A helper function for doing a raw ADC value to voltage conversion, essentially
*
* vdda_voltage * measurement_raw / 2^12
*
*/
uint32_t measurement_voltage = __HAL_ADC_CALC_DATA_TO_VOLTAGE(vdda_voltage, measurement_raw, ADC_RESOLUTION_12B);
stat = HAL_ADC_Stop(&hadc1);
return 0.0f;
}
This is CubeMX config, channel 10 and Vrefint enabled:
