File content as of revision 1:709e8e98f880:

// access F446RE internal ADC channels temp sensor, VBAT, VREF
//  based on pyboard implementation and analogin_api.c
// VBAT and temp are both channel 18, vref channel 17
#include "mbed.h"

#define PRREG(z) printf(#z" 0x%x\n",z) 

#define CORE_TEMP_V25          (4096*.76/3.3)  // (0.76v/3.3v)*(2^ADC resoultion)
#define CORE_TEMP_AVG_SLOPE    (4096*.0025/3.3)    // (2.5mv/3.3v)*(2^ADC resoultion)

//  VBAT to ADC goes through divider  /4  ref 13.11
#define VBAT_DIV (4)


static ADC_HandleTypeDef AdcHandle;

void adc_init() {
            // Enable ADC clock
        __ADC1_CLK_ENABLE();

        // Configure ADC
        AdcHandle.Instance = (ADC_TypeDef *)ADC1;
        AdcHandle.Init.ClockPrescaler        = ADC_CLOCKPRESCALER_PCLK_DIV2;
        AdcHandle.Init.Resolution            = ADC_RESOLUTION12b;
        AdcHandle.Init.ScanConvMode          = DISABLE;
        AdcHandle.Init.ContinuousConvMode    = DISABLE;
        AdcHandle.Init.DiscontinuousConvMode = DISABLE;
        AdcHandle.Init.NbrOfDiscConversion   = 0;
        AdcHandle.Init.ExternalTrigConvEdge  = ADC_EXTERNALTRIGCONVEDGE_NONE;
        AdcHandle.Init.ExternalTrigConv      = ADC_EXTERNALTRIGCONV_T1_CC1;
        AdcHandle.Init.DataAlign             = ADC_DATAALIGN_RIGHT;
        AdcHandle.Init.NbrOfConversion       = 1;
        AdcHandle.Init.DMAContinuousRequests = DISABLE;
        AdcHandle.Init.EOCSelection          = DISABLE;
        HAL_ADC_Init(&AdcHandle);
}

uint16_t adc_read_channel(uint32_t channel) {
    ADC_ChannelConfTypeDef sConfig;
    sConfig.Channel = channel;
    sConfig.Rank = 1;
    sConfig.SamplingTime = ADC_SAMPLETIME_3CYCLES;
    sConfig.Offset = 0;
    HAL_ADC_ConfigChannel(&AdcHandle, &sConfig);

    HAL_ADC_Start(&AdcHandle); // Start conversion

    // Wait end of conversion and get value
    if (HAL_ADC_PollForConversion(&AdcHandle, 10) == HAL_OK) {
        return (HAL_ADC_GetValue(&AdcHandle));
    } else {
        return 0;
    }
}

int main() {
    uint16_t val;
    float tempc, Vbat, Vcc;
    
    printf("\nSystemCoreClock %d  %s %s\n",SystemCoreClock,__TIME__,__DATE__);
    adc_init();
 
    val = adc_read_channel(ADC_CHANNEL_VBAT);
    Vbat = 3.3*VBAT_DIV*val/4096;
    printf("%d Vbat %.2f\n",val,Vbat);
    ADC->CCR=0;     // clear CCR to avoid conflicting use 
    val = adc_read_channel(ADC_CHANNEL_TEMPSENSOR);
    tempc = ((val - CORE_TEMP_V25) / CORE_TEMP_AVG_SLOPE) + 25.;
    printf("%d %.1f C\n",val, tempc);
    val = adc_read_channel(ADC_CHANNEL_VREFINT);
    Vcc = 4095*1.21/val;
    printf("%d Vcc %.2f\n",val,Vcc);

    PRREG(ADC1->CR1);
    PRREG(ADC1->CR2);
    PRREG(ADC->CCR);

}