entity Main {
    in clk: bit,
    out LED1: bit,
    out LED2: bit,
    out LED3: bit,
    out LED4: bit,
    out LED5: bit,
}

impl Main {
    // With a 12Mhz clock, count off every .5 seconds of ticks.
    def mut index: uint{..6000000};

    // Declare a state change every positive clock edge.
    on clk.posedge {
        if index == 6000000 - 1 {
            LED5 <= !LED5;
            index <= 0;
        } else {
            index <= index + 1;
        }
    }

    // Disable the other LEDs, as they otherwise would be
    // left floating and semi-lit. Because these definitions
    // are stateless (not mutable), we can declare them at the
    // top level.
    LED1 = 0;
    LED2 = 0;
    LED3 = 0;
    LED4 = 0;
}