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#include "vishnuADC.h"
#include "Arduino.h"
/**
* Constructor of the class
* @param io_pin_cs a byte indicating the pin to be use as the chip select pin (CS)
*/
ADS1118::ADS1118(uint8_t io_pin_cs) {
cs = io_pin_cs;
}
/**
* This method initialize the SPI port and the config register
*/
void ADS1118::begin() {
pinMode(cs, OUTPUT);
digitalWrite(cs, HIGH);
SPI.begin();
SPI.beginTransaction(SPISettings(SCLK, MSBFIRST, SPI_MODE1));
configRegister.bits={RESERVED, VALID_CFG, PULLUP, ADC_MODE, RATE_8SPS, SINGLE_SHOT, FSR_0256, DIFF_0_1, START_NOW}; //Default values
}
/**
* Getting the temperature in degrees celsius from the internal sensor of the ADS1118
* @return A double (32bits) containing the temperature in degrees celsius of the internal sensor
*/
double ADS1118::getTemperature() {
uint16_t convRegister;
uint8_t dataMSB, dataLSB, configMSB, configLSB, count=0;
if(lastSensorMode==TEMP_MODE)
count=1; //Lucky you! We don't have to read twice the sensor
else
configRegister.bits.sensorMode=TEMP_MODE; //Sorry but we will have to read twice the sensor
do{
digitalWrite(cs, LOW);
dataMSB = SPI.transfer(configRegister.byte.msb);
dataLSB = SPI.transfer(configRegister.byte.lsb);
configMSB = SPI.transfer(configRegister.byte.msb);
configLSB = SPI.transfer(configRegister.byte.lsb);
digitalWrite(cs, HIGH);
for(int i=0;i<CONV_TIME[configRegister.bits.rate];i++) //Lets wait the conversion time
delayMicroseconds(1000);
count++;
}while (count<=1); //We make two readings because the second reading is the temperature.
convRegister = ((dataMSB << 8) | (dataLSB))>>4;
if((convRegister<<2) >= 0x8000){
convRegister=((~convRegister)>>2)+1; //Converting to right-justified and applying binary twos complement format
return (double)(convRegister*0.03125*-1);
}
return (double)convRegister*0.03125;
}
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