105 lines
2.5 KiB
C
105 lines
2.5 KiB
C
#include <ring-light/temp-adc.h>
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#include <stm32f0xx.h>
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#define FLOAT_TO_S23_8(x) (int32_t)((x) * 1024.0f)
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static volatile uint16_t adc_results[16];
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static volatile int32_t vdd_lf_s23_8 = FLOAT_TO_S23_8(0);
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static volatile int32_t temp_lf_s23_8 = FLOAT_TO_S23_8(0);
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void temperature_adc_init(void)
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{
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RCC->AHBENR |= RCC_AHBENR_DMAEN;
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RCC->APB2ENR |= RCC_APB2ENR_ADCEN;
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/* ADC is mapped to DMA Channel 1 */
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SYSCFG->CFGR1 &= ~SYSCFG_CFGR1_DMA_RMP;
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DMA1_Channel1->CNDTR = 16;
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DMA1_Channel1->CPAR = (uint32_t)&ADC1->DR;
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DMA1_Channel1->CMAR = (uint32_t)&adc_results[0];
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DMA1_Channel1->CCR = DMA_CCR_PL_1 | DMA_CCR_MSIZE_0 | DMA_CCR_PSIZE_0 | DMA_CCR_MINC | DMA_CCR_CIRC | DMA_CCR_TCIE | DMA_CCR_EN;
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NVIC_EnableIRQ(DMA1_Channel1_IRQn);
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/* Calibrate the ADC */
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ADC1->CR = ADC_CR_ADCAL;
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while (ADC1->CR & ADC_CR_ADCAL);
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/* Dummy read the offset calibration value */
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ADC1->DR;
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ADC1->CR = 0;
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ADC1->CFGR1 = ADC_CFGR1_DMAEN | ADC_CFGR1_DMACFG | ADC_CFGR1_CONT;
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ADC1->CFGR2 = ADC_CFGR2_CKMODE_1;
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ADC1->SMPR = 7u;
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ADC->CCR |= ADC_CCR_TSEN | ADC_CCR_VREFEN;
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ADC1->CHSELR = (1<<17) | (1<<16);
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ADC1->CR = ADC_CR_ADEN | ADC_CR_ADSTART;
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}
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static uint32_t get_temp_sensor_cal(void)
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{
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const volatile uint16_t *cal;
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cal = (const volatile uint16_t *)0x1FFFF7B8UL;
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return (uint32_t)*cal;
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}
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int32_t temperature_adc_get_temp(void)
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{
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int32_t temp;
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const int32_t slope = FLOAT_TO_S23_8(5.336f);
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temp = ((temp_lf_s23_8 / 16) * vdd_lf_s23_8 / FLOAT_TO_S23_8(3.3)) * 16;
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temp = (get_temp_sensor_cal() << 10) - temp;
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temp = (temp * 10 / slope) + 300;
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return temp;
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}
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static uint32_t get_vrefint_cal(void)
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{
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const volatile uint16_t *cal;
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cal = (const volatile uint16_t *)0x1FFFF7BAUL;
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return (uint32_t)*cal;
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}
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static void process_adc_samples(void)
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{
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int i;
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uint32_t temp_val = 0;
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uint32_t vref_val = 0;
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int32_t vdd_s23_8;
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int32_t temp_s23_8;
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const uint32_t ref_cal = get_vrefint_cal();
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for (i = 0; i < 8; i++) {
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temp_val += adc_results[2 * i];
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vref_val += adc_results[(2 * i) + 1];
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}
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vref_val >>= 3;
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temp_val >>= 3;
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vdd_s23_8 = (FLOAT_TO_S23_8(3.3f) * ref_cal) / vref_val;
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temp_s23_8 = temp_val << 10;
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/* Moving average filter */
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vdd_lf_s23_8 = (vdd_lf_s23_8 * FLOAT_TO_S23_8(0.78125f) + vdd_s23_8 * FLOAT_TO_S23_8(0.21875f)) >> 10;
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temp_lf_s23_8 = (int32_t)((((int64_t)temp_lf_s23_8 * (int64_t)FLOAT_TO_S23_8(0.78125f)) + temp_s23_8 * FLOAT_TO_S23_8(0.21875f)) / 1024);
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}
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void DMA_CH1_IRQHandler(void)
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{
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uint32_t isr;
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isr = DMA1->ISR;
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DMA1->IFCR = isr & 0xF;
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if (isr & DMA_ISR_TCIF1) {
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process_adc_samples();
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}
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}
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