/* Sample program to read the analog value of the pin connected to the pontentiometer.
 * The potentiometer on the Wytec EduBase board is connected pin 28.
 * The value is sent to the Serial monitor. The ADC has 12 bits so the value has the 
 * range of 0 - 4095. The upper 4 bits of the conversion result is also written to
 * the LEDs.
 */
 
/* 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("Potentiometer:");

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

/* Tiva TM4C123 */ //const int pot = PE_2;
const int pot = 28;

void loop()
{
    int potValue;
    
    // read the voltage fromm ADC
    potValue = analogRead(pot);
    
    // write it to the Serial monitor
    Serial.print("  potentiometer value = ");
    Serial.println(potValue, DEC);
    
    digitalGroupWrite(LED, 4, potValue >> 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);
    }
}