Experiment 2: Cascaded Counter

counter2.ino

// the setup function runs once when you press reset or power the board

byte counter1 = 0; // define variables
byte counter2 = 0;

void setup() {

    // initialize Ports B and C pins 0-5 as outputs.
    DDRB = 0b00111111;
    DDRC = 0b00111111;

    PORTB = 0; // both ports start from zero
    PORTC = 0;
}

// the loop function runs over and over again forever

void loop() {

    PORTB = counter2; // counter2 is our "seconds" counter
    PORTC = counter1; // counter1 is our "minutes" counter

    counter2++; // using the tip we learnt earlier

    if (counter2 > 59) {
        counter2 = 0;
        counter1++;

        if (counter1 > 59) {
            counter1 = 0;
        }
    }

    delay(1000); // again, reduce this delay if necessary to speed things up.
}