void setup() {
    chipName("SN74LS283"); // 4-bit binary full adder with fast carry
    logicFamily(TTL);

    pin(1, "S2", OUTPUT);
    pin(2, "B2");
    pin(3, "A2");
    pin(4, "S1", OUTPUT);
    pin(5, "A1");
    pin(6, "B1");
    pin(7, "C0");
    pin(8, "GND", GROUND);
    pin(9, "C4", OUTPUT);
    pin(10, "S4", OUTPUT);
    pin(11, "B4");
    pin(12, "A4");
    pin(13, "S3", OUTPUT);
    pin(14, "A3");
    pin(15, "B3");
    pin(16, "VCC", POWER);
}

void loop() {
    // Read the inputs A and B (4 bits each) from the addressable pins
    int a = digitalReadNibble(5, 3, 14, 12);
    int b = digitalReadNibble(6, 2, 15, 11);

    // Perform the addition of A, B, and the carry input C0 (from pin 7)
    int s = a + b + (digitalRead(7) ? 1 : 0);

    digitalWriteNibble(4, 1, 13, 10, s);

    // Set the carry output (C4) based on the carry bit (bit 4 of the sum)
    digitalWrite(9, (s & 0x10) != 0);
}