Sha256: 55e1311fdf11a1781350ebd22ad45e05ed500c4bb3128367b434ca115b5da221
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Versions: 54
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Stored size: 1.36 KB
Contents
#include "Types.h"
#include "AdcTemperatureSensor.h"
static inline uint32 ConvertAdcCountsToPicovolts(uint32 counts);
static inline uint16 ConvertPicovoltsToMillivolts(uint32 picovolts);
//
// PUBLIC METHODS
//
void Adc_StartTemperatureSensorConversion(void)
{
AT91C_BASE_ADC->ADC_CR = AT91C_ADC_START;
}
bool Adc_TemperatureSensorSampleReady(void)
{
return ((AT91C_BASE_ADC->ADC_SR & AT91C_ADC_EOC4) == AT91C_ADC_EOC4);
}
uint16 Adc_ReadTemperatureSensor(void)
{
uint32 picovolts = ConvertAdcCountsToPicovolts(AT91C_BASE_ADC->ADC_CDR4);
return ConvertPicovoltsToMillivolts(picovolts);
}
//
// PRIVATE HELPERS
//
static inline uint32 ConvertAdcCountsToPicovolts(uint32 counts)
{
// ADC bit weight at 10-bit resolution with 3.0V reference = 2.9296875 mV/LSB
uint32 picovoltsPerAdcCount = 2929688;
// Shift decimal point by 6 places to preserve accuracy in fixed-point math
return counts * picovoltsPerAdcCount;
}
static inline uint16 ConvertPicovoltsToMillivolts(uint32 picovolts)
{
const uint32 halfMillivoltInPicovolts = 500000;
const uint32 picovoltsPerMillivolt = 1000000;
// Add 0.5 mV to result so that truncation yields properly rounded result
picovolts += halfMillivoltInPicovolts;
// Divide appropriately to convert to millivolts
return (uint16)(picovolts / picovoltsPerMillivolt);
}
Version data entries
54 entries across 39 versions & 1 rubygems