ADC + SD Card

Using Arduino Networking, Protocols, and Devices
8

Heres my new get voltage function

double Adc::getVoltage()
{
    
    while(digitalRead(RDY)); //once RDY pin is pulled low
        
    digitalWrite(_pin, LOW);//pull CS low
    
    selectADC();

    delay(100); // a dealy here could help
    
    SPI.transfer(0x5C); // Channel 1 Data Register
    //(0101 1100)
    
    byte inputBytes[4];
    inputBytes[3] = 0x00; //MSB all 0's
    inputBytes[2] = SPI.transfer(0x00);
    inputBytes[1] = SPI.transfer(0x00);
    inputBytes[0] = SPI.transfer(0x00);
    
    digitalWrite(_pin, HIGH);
    
    convertToVoltage(inputBytes);
    
    const char dummy = 'D';
    
    writeToSD(dummy);
    
    return 0;
}

and the convert to voltage function i'm using:

void Adc::convertToVoltage(byte inputBytes[4]) {
    double MSB = inputBytes[2];
    double SB = inputBytes[1];
    double LSB = inputBytes[0];
    
    double result = (MSB * 256 * 256);
    result = result + (SB * 256);
    result = result + LSB ;
    result = (result * 6.6 / 256 / 256 / 256) - 3.3;
    
    Serial.println("result is");
    Serial.print(result);
    Serial.print(" volts");
    
    }