85 lines
1.7 KiB
C
85 lines
1.7 KiB
C
/*
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* adc.cpp
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*
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* Created on: 03.10.2014
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* Author: wn
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*/
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#include <msp430g2553.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <stdbool.h>
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#include <float.h>
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#include "measure.h"
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#include "PontCoopScheduler.h"
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#include "pattern.h"
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const float R_REF = 3000.0;
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const uint16_t N_MAX = 1023;
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const float PT1000_R0 = 1000.0;
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const float PT1000_Coeff = 3.85e-3;
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const uint32_t MEASURE_CYCLE = 20;
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const uint32_t MEASURE_FETCH_RESULT_DELAY = 5;
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const uint8_t AVERAGING_CYCLES = 50;
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void measureInit() {
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ADC10CTL0 = SREF1 | ADC10SHT_3 | ADC10SR | REFOUT | REFON | REF2_5V | ADC10ON;
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ADC10CTL1 = INCH_3;
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ADC10AE0 = BIT3;
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}
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void measureCollectAndProcessConversion();
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void measureStartConversion(void *handleArg) {
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ADC10CTL0 |= ENC | ADC10SC;
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schAdd(measureCollectAndProcessConversion, NULL, MEASURE_FETCH_RESULT_DELAY, 0);
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}
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void measureCollectAndProcessConversion() {
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static uint32_t averagingSum = 0;
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static uint8_t averagingCnt = 0;
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uint16_t n = 0xffff;
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if ((ADC10CTL0 & ADC10IFG) != 0) {
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n = ADC10MEM;
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ADC10CTL0 &= ~(ADC10IFG | ENC);
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}
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if (n != 0xffff) {
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averagingSum += n;
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averagingCnt++;
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}
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if (averagingCnt == AVERAGING_CYCLES) {
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uint32_t nAvg = averagingSum / averagingCnt;
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// process adcValue
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// store result in variable temperature
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float r = 0.0;
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if (nAvg == 0) {
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r = 0.0;
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} else if (nAvg == N_MAX) {
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r = FLT_MAX;
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} else {
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r = R_REF / ((((float)N_MAX) / ((float)nAvg)) - 1.0);
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}
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float t = (r / PT1000_R0 - 1) / PT1000_Coeff;
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uint8_t temperature = (t < 0) ? 0 : ((uint8_t)t);
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// do something with the temperature
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patternSetTemperature(temperature);
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averagingCnt = 0;
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averagingSum = 0;
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}
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}
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