after setting up and starting the adc it would give me the correct values but would randomly jump close to zero frequently.
below is a snipbit of my code that is initializing the ADC1. i am aware that i went over board on the for loops delays but i was trying to see if the issue was being caused by the lack of time needed to stabilize or calibrate. if anyone has a better idea on how i should fix this, please let me know. I'm a little new with this microcontroller and coding in general.
RCC->CFGR |= RCC_CFGR_ADCPRE_DIV6; //sets ADC clock freguency to 12mhz accoring to datasheet
RCC->APB2ENR |= RCC_APB2ENR_ADC1EN | RCC_APB2ENR_AFIOEN; //enable ADC and alt fuction pins
RCC->AHBENR |= RCC_AHBENR_DMA1EN; //enable DMA
ADC1->SMPR2 |= ADC_SMPR2_SMP7_0 | ADC_SMPR2_SMP7_1 | ADC_SMPR2_SMP7_2; // setting sample rates to max
ADC1->SMPR2 |= ADC_SMPR2_SMP8_0 | ADC_SMPR2_SMP8_1 | ADC_SMPR2_SMP8_2; // setting sample rates to max
ADC1->SMPR2 |= ADC_SMPR2_SMP9_0 | ADC_SMPR2_SMP9_1 | ADC_SMPR2_SMP9_2; // setting sample rates to max
ADC1->SQR1 |= 3 << 20; //turning sequence mode on
ADC1->SQR3 |= 9 << 0; // setting channel 9 as the first in sequence
ADC1->SQR3 |= 8 << 5; // setting channel 8 as the second in sequence
ADC1->SQR3 |= 7 << 10; // setting channel 7 as the third in sequence
ADC1->CR1 |= ADC_CR1_SCAN; // setting ADC to scan mode
ADC1->CR2 |= ADC_CR2_DMA; // turning on DMa for ADC
DMA1_Channel1 ->CPAR = (uint32_t)(&(ADC1->DR)); // passing data register of ADC to DMA
DMA1_Channel1 ->CMAR = (uint32_t)currentSen; // passing array to DMA
DMA1_Channel1 ->CNDTR = 3; // set DMa to count 3 times
DMA1_Channel1 ->CCR |= DMA_CCR1_CIRC | DMA_CCR1_MINC | DMA_CCR1_MSIZE_0 | DMA_CCR1_PSIZE_0; // DMA settings
DMA1_Channel1 ->CCR |= DMA_CCR1_EN; // enable DMA
ADC1->CR2 |= ADC_CR2_CONT; // turn on ADC continuous mode
ADC1->CR2 |= ADC_CR2_ADON; // turn on ADC
ADC1->CR2 |= ADC_CR2_CAL; //Enable calibration
while ((ADC1->CR2 >> 2) & 0x1UL); //Wait until calibration completed
ADC1->CR2 |= ADC_CR2_ADON; //Set CR2_ADON again to turn on ADC and start converting
for(int y = 0; y < 1000000; y++){}
below is a snipbit of my code that is initializing the ADC1. i am aware that i went over board on the for loops delays but i was trying to see if the issue was being caused by the lack of time needed to stabilize or calibrate. if anyone has a better idea on how i should fix this, please let me know. I'm a little new with this microcontroller and coding in general.
RCC->CFGR |= RCC_CFGR_ADCPRE_DIV6; //sets ADC clock freguency to 12mhz accoring to datasheet
RCC->APB2ENR |= RCC_APB2ENR_ADC1EN | RCC_APB2ENR_AFIOEN; //enable ADC and alt fuction pins
RCC->AHBENR |= RCC_AHBENR_DMA1EN; //enable DMA
ADC1->SMPR2 |= ADC_SMPR2_SMP7_0 | ADC_SMPR2_SMP7_1 | ADC_SMPR2_SMP7_2; // setting sample rates to max
ADC1->SMPR2 |= ADC_SMPR2_SMP8_0 | ADC_SMPR2_SMP8_1 | ADC_SMPR2_SMP8_2; // setting sample rates to max
ADC1->SMPR2 |= ADC_SMPR2_SMP9_0 | ADC_SMPR2_SMP9_1 | ADC_SMPR2_SMP9_2; // setting sample rates to max
ADC1->SQR1 |= 3 << 20; //turning sequence mode on
ADC1->SQR3 |= 9 << 0; // setting channel 9 as the first in sequence
ADC1->SQR3 |= 8 << 5; // setting channel 8 as the second in sequence
ADC1->SQR3 |= 7 << 10; // setting channel 7 as the third in sequence
ADC1->CR1 |= ADC_CR1_SCAN; // setting ADC to scan mode
ADC1->CR2 |= ADC_CR2_DMA; // turning on DMa for ADC
DMA1_Channel1 ->CPAR = (uint32_t)(&(ADC1->DR)); // passing data register of ADC to DMA
DMA1_Channel1 ->CMAR = (uint32_t)currentSen; // passing array to DMA
DMA1_Channel1 ->CNDTR = 3; // set DMa to count 3 times
DMA1_Channel1 ->CCR |= DMA_CCR1_CIRC | DMA_CCR1_MINC | DMA_CCR1_MSIZE_0 | DMA_CCR1_PSIZE_0; // DMA settings
DMA1_Channel1 ->CCR |= DMA_CCR1_EN; // enable DMA
ADC1->CR2 |= ADC_CR2_CONT; // turn on ADC continuous mode
ADC1->CR2 |= ADC_CR2_ADON; // turn on ADC
ADC1->CR2 |= ADC_CR2_CAL; //Enable calibration
while ((ADC1->CR2 >> 2) & 0x1UL); //Wait until calibration completed
ADC1->CR2 |= ADC_CR2_ADON; //Set CR2_ADON again to turn on ADC and start converting
for(int y = 0; y < 1000000; y++){}
