70 lines
1.5 KiB
C
70 lines
1.5 KiB
C
#include <xc.h>
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#include "measure.h"
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#include "mcc_generated_files/mcc.h"
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#define VOLTAGE_CHANNEL 0x5
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#define CURRENT_CHANNEL 0x6
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#define ADC_RESOLUTION (1024 - 1)
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#define ADC_REFH 3300
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#define GAIN 66
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#define RESISTOR 3
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// Number of samples to do the averaging during measures
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#define AVERAGE_SAMPLES 8
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void adc_init(void)
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{
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// TODO -> complete adc initialisation
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//offsetCurrent = measure_current(0);
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}
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/**
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* Read one ADC channel. This function is only
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* local to this file.
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*
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* @param channel : the channel to be measured
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* @return the ADC read value
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*/
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static uint16_t measure_adc(uint8_t channel) {
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return (uint16_t) (ADC_GetConversion(channel));
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}
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/**
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*
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* @return
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*/
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uint16_t measure_voltage() {
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uint32_t sum = 0;
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// Make an average
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for(int i = 0; i < AVERAGE_SAMPLES; i++) {
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sum += measure_adc(VOLTAGE_CHANNEL);
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}
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sum /= AVERAGE_SAMPLES;
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// Convert sum from bits to mV
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sum = (sum * ADC_REFH) / ADC_RESOLUTION;
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return (uint16_t)(sum);
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}
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uint16_t measure_current(uint16_t offset) {
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uint32_t sum = 0;
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for(int i = 0; i< AVERAGE_SAMPLES; i++){
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sum += measure_adc(CURRENT_CHANNEL);
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}
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uint32_t m = (sum / AVERAGE_SAMPLES); // m is bits
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m = (m * ADC_REFH) / ADC_RESOLUTION; // m is mV
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m *= 1000; // m is uV
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m /= GAIN;
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m /= RESISTOR; // m is uA
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if(m <= offset){
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m = 0;
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} else {
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m -= offset;
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}
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return (uint16_t)m;
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} |