measure.c

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#include <xc.h>
 
#include "measure.h"
#include "mcc_generated_files/mcc.h"
 
#define VOLTAGE_CHANNEL 0x5
#define CURRENT_CHANNEL 0x6
#define ADC_RESOLUTION  (1024 - 1)
#define ADC_REFH        3300
#define GAIN            66
#define RESISTOR        3
 
// Number of samples to do the averaging during measures
#define AVERAGE_SAMPLES 8
 
void adc_init(void)
{
    // TODO -> complete adc initialisation
    //offsetCurrent = measure_current(0);
 
}
 
static uint16_t measure_adc(uint8_t channel)
{
    return (uint16_t) (ADC_GetConversion(channel));
}
 
 
 
uint16_t measure_voltage()
{
    uint32_t sum = 0;
    
    for(int i = 0; i < AVERAGE_SAMPLES; i++) {
        sum += measure_adc(VOLTAGE_CHANNEL);
    }
    sum /= AVERAGE_SAMPLES;
    sum = (sum * ADC_REFH) / ADC_RESOLUTION;
    return (uint16_t)(sum);
}
 
uint16_t measure_current(uint16_t offset)
{
    uint32_t sum = 0;
    for(int i = 0; i< AVERAGE_SAMPLES; i++){
        sum += measure_adc(CURRENT_CHANNEL);
    } 
    uint32_t m = (sum / AVERAGE_SAMPLES);   // m is bits
    m = (m * ADC_REFH) / ADC_RESOLUTION;    // m is mV
    m *= 1000;                              // m is uV
    m /= GAIN;
    m /= RESISTOR;                          // m is uA
    if(m <= offset){
        m = 0;
    } else {
        m -= offset;
    }
    
    return (uint16_t)m;
}