/* Sample program to read the analog value of the pin connected to the photosensor.
 * The photosensor on the Wytec EduBase board is connected pin 27. The value is sent to the 
 * Serial monitor. and the upper 4 bits of the conversion result is also written to the LEDs.
 * Shield the photosensor from light and the analog value decreases.
 */
 
/* Tiva TM4C123 */ //const int LED[] = {PB_0, PB_1, PB_2, PB_3};
const int LED[] = {3, 4, 19, 38};

void setup()
{
    Serial.begin(9600);
    Serial.println("Photosensor:");

    // initialize LED for display
    for (int i = 0; i < 4; i++)
    {
      pinMode(LED[i], OUTPUT);
    }
    
    digitalGroupWrite(LED, 4, 0);
}

/* Tiva TM4C123 */ //const int photo = PE_1;
const int photo = 27;

void loop()
{
    int photoValue;
    
    // read the voltage fromm ADC
    photoValue = analogRead(photo);
    
    // write it to the Serial monitor
    Serial.print("  Photosensor value = ");
    Serial.println(photoValue, DEC);
    
    digitalGroupWrite(LED, 4, photoValue >> 8);  // and write it to the LEDs
    delay(100);
}

// write to a group of output pins
void digitalGroupWrite(const int* group, int length, int data)
{
    for (length--; length >= 0; length--)
    {
        digitalWrite(group[length], data & (1 << length) ? HIGH : LOW);
    }
}