STM32L052 Analog-to-digital converter on registers - c

Question

I went through the entire configuration of the Analog-to-digital converter [ADC]. When I worked on the registers, I made a mistake somewhere. Below are the configurations. The debugger via ST-Link after connecting 3.3 [V] to pins used in the project, during the measurement assigns them a value of 0x00 which indicates a failure. What am I doing wrong?
int main(void)
{
RCC->APB2ENR |= RCC_APB2ENR_ADC1EN;
//ADC attach
RCC->IOPENR = RCC_IOPENR_GPIOAEN | RCC_IOPENR_GPIOBEN;
GPIOB->MODER = GPIO_MODER_MODE14_1 | GPIO_MODER_MODE15_1;
//ADC_IN8 & ADC_IN9
/* configure ADC */
ADC1->ISR &= ~ADC_ISR_EOCAL & ~ADC_ISR_AWD;
//calibration flag, WATCHDOG flag
ADC1->ISR |= ADC_ISR_ADRDY;
ADC1->CR &= ~ADC_CR_ADSTART;
//The software is allowed to write smp bit only when ADSTART=0
ADC1->SMPR |= ADC_SMPR_SMP_0 | ADC_SMPR_SMP_1 | ADC_SMPR_SMP_2;
//111: 160.5 ADC clock cycles
ADC1->CFGR1 &= ~ADC_CFGR1_SCANDIR;
//Scan Direction 0: Upward scan (from CHSEL0 to CHSEL18)
ADC1->CFGR1 |= ADC_CFGR1_AWDCH_3 | ADC_CFGR1_AWDEN | ADC_CFGR1_WAIT | ADC_CFGR1_CONT | ADC_CFGR1_AUTOFF;
//AWDCH[4:0]: Analog watchdog channel selection, Continuous Mode
ADC->CCR |= ADC_CCR_LFMEN | ADC_CCR_VREFEN;
//Low Frequency Mode, V REFINT enable
ADC1->CHSELR |= ADC_CHSELR_CHSEL8 | ADC_CHSELR_CHSEL9 | ADC_CHSELR_CHSEL17;
//Channel Select 8 & 9
ADC1->IER |= ADC_IER_EOCIE | ADC_IER_EOSEQIE | ADC_IER_OVRIE | ADC_IER_EOSMPIE;
NVIC_EnableIRQ(ADC1_COMP_IRQn);
NVIC_SetPriority(ADC1_COMP_IRQn,3);
while(1)
{
ADC1->CR |= ADC_CR_ADEN;// | ADC_CR_ADSTART;
//Start the ADC conversion
while ((ADC1->ISR & ADC_ISR_ADRDY));
//Wait for stand up
while ((ADC1->ISR & ADC_ISR_EOC));
//wait for conversion flag
ADC1->CR |= ADC_CR_ADCAL;
//End of the calibration
delay(100);
uint16_t napiecie = ADC1->DR;
uint8_t hi = ((napiecie >> 8) & 0xff);
uint8_t lo = ((napiecie >> 0) & 0xff);
//DISABLE ADC
if ((ADC1->CR & ADC_CR_ADSTART) != 0){
ADC1->CR |= ADC_CR_ADSTP;
while ((ADC1->CR & ADC_CR_ADSTP) != 0);
}
ADC1->CR |= ADC_CR_ADDIS; //ADC disable command
while ((ADC1->CR & ADC_CR_ADEN) != 0);
ADC1->CR &= ~ADC_CR_ADSTART & ~ADC_CR_ADEN;
//ADC1->CR &= ~ADC_ISR_ADRDY; //Clear the ADRDY bit in ADC_ISR register by programming this bit to 1 (optional).
}
void ADC1_COMP_IRQHandler(void)
/* Interupt ADC */
{
if(ADC1->ISR & ADC_ISR_EOC){
uint16_t napiecie = ADC1->DR;
uint8_t hi = ((napiecie >> 8) & 0xff);
uint8_t lo = ((napiecie >> 0) & 0xff);
}
}

Answer 1

Two times you used lines like
ADC1->ISR &= ~ADC_ISR_EOCAL | ~ADC_ISR_AWD;
which looks really strange to me, as if the defines are 1 bit wide, which they most likely are, their bitwise OR is 0xFFFFFFFF (all F, no 0) and you're not changing the ISR and the CR (later in the code) at all! You need to use a bitwise AND, no?
ADC1->ISR &= ~ADC_ISR_EOCAL & ~ADC_ISR_AWD;
...
ADC1->CR &= ~ADC_CR_ADSTART & ~ADC_CR_ADEN;
Else some working code is available at https://electronics.stackexchange.com/questions/287073/get-internal-temperature-or-voltage-stm32l0/287162
https://github.com/ChristopherJD/STM32L053R8/blob/master/Intern_Project/ADC.c
and https://www.digikey.com/eewiki/pages/viewpage.action?pageId=47644832