main-loop.rs

    //  Get GPIO Port C, which also enables the Advanced Peripheral Bus 2 (APB2) clock for Port C.
    let mut gpioc = bluepill.GPIOC.split(&mut rcc.apb2);

    //  Use Pin PC 13 of the Blue Pill for GPIO Port C. Select Output Push/Pull mode for the pin, which is connected to our LED.
    let mut led = gpioc.pc13.into_push_pull_output(&mut gpioc.crh);
    ...
    //  Loop forever.
    loop {
        //  Output 3.3V on the LED Pin and show a message in OpenOCD console.
        led.set_high();
        writeln!(debug_out, "LED is ON!").unwrap();

        //  Wait 1,000 millisec (1 sec).
        delay.delay_ms(1_000_u16);

        //  Output 0V on the LED Pin and show a message in OpenOCD console.
        led.set_low();
        writeln!(debug_out, "LED is OFF!").unwrap();

        //  Wait 1,000 millisec (1 sec).
        delay.delay_ms(1_000_u16);
    }