diff options
| -rw-r--r-- | fw/adc.c | 52 | ||||
| -rw-r--r-- | fw/main.c | 4 |
2 files changed, 7 insertions, 49 deletions
@@ -26,7 +26,7 @@ enum adc_channels { TEMP_CH, NCH }; -static volatile uint16_t adc_buf[NCH]; +static volatile uint16_t adc_buf[1024]; void adc_init(void) { /* The ADC is used for temperature measurement. To compute the temperature from an ADC reading of the internal @@ -35,15 +35,13 @@ void adc_init(void) { * The ADC is triggered by compare channel 4 of timer 1. The trigger is set to falling edge to trigger on compare * match, not overflow. */ - ADC1->CFGR1 = ADC_CFGR1_DMAEN | ADC_CFGR1_DMACFG | (2<<ADC_CFGR1_EXTEN_Pos) | (1<<ADC_CFGR1_EXTSEL_Pos); + ADC1->CFGR1 = ADC_CFGR1_DMAEN | ADC_CFGR1_DMACFG | (2<<ADC_CFGR1_EXTEN_Pos) | (1<<ADC_CFGR1_EXTSEL_Pos) | ADC_CFGR1_CONT; /* Clock from PCLK/4 instead of the internal exclusive high-speed RC oscillator. */ ADC1->CFGR2 = (2<<ADC_CFGR2_CKMODE_Pos); /* Use PCLK/4=12MHz */ /* Sampling time 13.5 ADC clock cycles -> total conversion time 2.17us*/ ADC1->SMPR = (2<<ADC_SMPR_SMP_Pos); - /* Internal VCC and temperature sensor channels */ - ADC1->CHSELR = ADC_CHSELR_CHSEL0 | ADC_CHSELR_CHSEL1 | ADC_CHSELR_CHSEL16 | ADC_CHSELR_CHSEL17; - /* Enable internal voltage reference and temperature sensor */ - ADC->CCR = ADC_CCR_TSEN | ADC_CCR_VREFEN; + + ADC1->CHSELR = ADC_CHSELR_CHSEL0 | ADC_CHSELR_CHSEL1; /* Perform ADC calibration */ ADC1->CR |= ADC_CR_ADCAL; while (ADC1->CR & ADC_CR_ADCAL) @@ -55,7 +53,7 @@ void adc_init(void) { /* Configure DMA 1 Channel 1 to get rid of all the data */ DMA1_Channel1->CPAR = (unsigned int)&ADC1->DR; DMA1_Channel1->CMAR = (unsigned int)&adc_buf; - DMA1_Channel1->CNDTR = NCH; + DMA1_Channel1->CNDTR = sizeof(adc_buf)/sizeof(adc_buf[0]); DMA1_Channel1->CCR = (0<<DMA_CCR_PL_Pos); DMA1_Channel1->CCR |= DMA_CCR_CIRC /* circular mode so we can leave it running indefinitely */ @@ -70,49 +68,9 @@ void adc_init(void) { NVIC_SetPriority(DMA1_Channel1_IRQn, 3<<5); } -uint16_t buf_a[256]; -uint16_t buf_b[256]; -int bufp = 0; - void DMA1_Channel1_IRQHandler(void) { - /* This interrupt takes either 1.2us or 13us. It can be pre-empted by the more timing-critical UART and LED timer - * interrupts. */ - static int count = 0; /* oversampling accumulator sample count */ - static uint32_t adc_aggregate[NCH] = {0}; /* oversampling accumulator */ - /* Clear the interrupt flag */ DMA1->IFCR |= DMA_IFCR_CGIF1; - for (int i=0; i<NCH; i++) - adc_aggregate[i] += adc_buf[i]; - - if (++count == (1<<ADC_OVERSAMPLING)) { - for (int i=0; i<NCH; i++) - adc_aggregate[i] >>= ADC_OVERSAMPLING; - /* This has been copied from the code examples to section 12.9 ADC>"Temperature sensor and internal reference - * voltage" in the reference manual with the extension that we actually measure the supply voltage instead of - * hardcoding it. This is not strictly necessary since we're running off a bored little LDO but it's free and - * the current supply voltage is a nice health value. - */ - adc_data.adc_vcc_mv = (3300 * VREFINT_CAL)/(adc_aggregate[VREF_CH]); - - int64_t read = adc_aggregate[TEMP_CH] * 10 * 10000; - int64_t vcc = adc_data.adc_vcc_mv; - int64_t cal = TS_CAL1 * 10 * 10000; - adc_data.adc_temp_celsius_tenths = 300 + ((read/4096 * vcc) - (cal/4096 * 3300))/43000; - - adc_data.adc_vmeas_a_mv = (adc_aggregate[VMEAS_A]*13300L)/4096 * vcc / 3300; - adc_data.adc_vmeas_b_mv = (adc_aggregate[VMEAS_B]*13300L)/4096 * vcc / 3300; - - buf_a[bufp] = adc_data.adc_vmeas_a_mv; - buf_b[bufp] = adc_data.adc_vmeas_b_mv; - if (++bufp >= sizeof(buf_a)/sizeof(buf_a[0])) { - bufp = 0; - } - - count = 0; - for (int i=0; i<NCH; i++) - adc_aggregate[i] = 0; - } } @@ -69,8 +69,8 @@ int main(void) { TIM1->CCR4 = 1; TIM1->DIER = TIM_DIER_UIE; - TIM1->PSC = SystemCoreClock/1000000 - 1; /* 1.0us/tick */ - TIM1->ARR = 20-1; /* 20us */ + TIM1->PSC = SystemCoreClock/500000 - 1; /* 0.5us/tick */ + TIM1->ARR = 25-1; /* Preload all values */ TIM1->EGR |= TIM_EGR_UG; TIM1->CR1 = TIM_CR1_ARPE; |