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Příklad inicializace ADC převodníku s ukládáním dat do DMA. Převodník běží v nekonečné smyčce a vždy provede počet vzorků podle #define ADC_AVG_SIZE 16 . Po navzorkování 16 vzorků se data ukládají cirkulárně opět od začátku pole ADCvalueDMA.
#define ADC_AVG_SIZE 16
ADCvalueDMA
#define ADC_AVG_SIZE 16 uint16_t ADCvalueDMA[ADC_AVG_SIZE]; void ADCInitDMA(void){ // --- ADC Part --- RCC->APB2ENR |= RCC_APB2ENR_ADC1EN; ADC1->SQR3 |= 0 << ADC_SQR3_SQ1_Pos; ADC1->SMPR2 |= 7 << ADC_SMPR2_SMP0_Pos; //480 cycles ADC1->CR2 |= ADC_CR2_ADON | ADC_CR2_CONT; RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN; GPIOA->MODER |= GPIO_MODE_ANALOG << GPIO_MODER_MODE0_Pos; // --- DMA part --- RCC->AHB1ENR |= RCC_AHB1ENR_DMA2EN; // enable clock // CH0 selection, Memory and peripheral data size is 16 bits, P->M direction, circular mode DMA2_Stream0->CR |= 0x00 << DMA_SxCR_CHSEL_Pos; // CH0 select // Peripheral and Memory have size 16bits DMA2_Stream0->CR |= (0x01 << DMA_SxCR_MSIZE_Pos) | (0x01 << DMA_SxCR_PSIZE_Pos); DMA2_Stream0->CR |= 0x00 << DMA_SxCR_DIR_Pos; // Peripheral to Memory direction DMA2_Stream0->CR |= DMA_SxCR_CIRC; // Circular DMA2_Stream0->CR |= DMA_SxCR_MINC; // Index increment for Memory destination DMA2_Stream0->NDTR = ADC_AVG_SIZE; // Number of data DMA2_Stream0->M0AR = (uint32_t*) ADCvalueDMA; // Target variable (array) DMA2_Stream0->PAR = &ADC1->DR; DMA2_Stream0->CR |= DMA_SxCR_EN; ADC1->CR2 |= ADC_CR2_DMA | ADC_CR2_DDS; ADC1->CR2 |= ADC_CR2_SWSTART; } int main(void){ ADCInitDMA(); while (1){ for(int i = 0; i < ADC_AVG_SIZE; i++){ // process ADC values from ADCvalueDMA[i] } } }