class NullIO : public IO {

public:
    NullIO()
    {
    }
    ~NullIO()
    {
    }

    // Serial
    virtual void SerialBegin(uint8_t serialDevice, int baudrate) {
        MICROFLO_DEBUG(debug, DebugLevelError, DebugIoOperationNotImplemented);
    }
    virtual long SerialDataAvailable(uint8_t serialDevice) {
        MICROFLO_DEBUG(debug, DebugLevelError, DebugIoOperationNotImplemented);
        return 0;
    }
    virtual unsigned char SerialRead(uint8_t serialDevice) {
        MICROFLO_DEBUG(debug, DebugLevelError, DebugIoOperationNotImplemented);
        return '\0';
    }
    virtual void SerialWrite(uint8_t serialDevice, unsigned char b) {
        MICROFLO_DEBUG(debug, DebugLevelError, DebugIoOperationNotImplemented);
    }

    // Pin config
    virtual void PinSetMode(MicroFlo::PinId pin, IO::PinMode mode) {
        MICROFLO_DEBUG(debug, DebugLevelError, DebugIoOperationNotImplemented);
    }
    virtual void PinSetPullup(MicroFlo::PinId pin, IO::PullupMode mode) {
        // TODO: support pullup/pulldown config on common boards like RPi
        // Not exposed in sysfs, need to prod registers directly.
        // http://elinux.org/RPi_Low-level_peripherals#GPIO_Pull_Up.2FPull_Down_Register_Example
        MICROFLO_DEBUG(debug, DebugLevelError, DebugIoOperationNotImplemented);
    }

    // Digital
    virtual void DigitalWrite(MicroFlo::PinId pin, bool val) {
        MICROFLO_DEBUG(debug, DebugLevelError, DebugIoOperationNotImplemented);
    }
    virtual bool DigitalRead(MicroFlo::PinId pin) {
        MICROFLO_DEBUG(debug, DebugLevelError, DebugIoOperationNotImplemented);
        return false;
    }

    // Analog
    virtual long AnalogRead(MicroFlo::PinId pin) {
        MICROFLO_DEBUG(debug, DebugLevelError, DebugIoOperationNotImplemented);
        return 0;
    }
    virtual void PwmWrite(MicroFlo::PinId pin, long dutyPercent) {
        MICROFLO_DEBUG(debug, DebugLevelError, DebugIoOperationNotImplemented);
    }

    // Timer
    virtual long TimerCurrentMs() {
        MICROFLO_DEBUG(debug, DebugLevelError, DebugIoOperationNotImplemented);
        return 0;
    }

    virtual void AttachExternalInterrupt(uint8_t interrupt, IO::Interrupt::Mode mode,
                                        IOInterruptFunction func, void *user) {
        MICROFLO_DEBUG(debug, DebugLevelError, DebugIoOperationNotImplemented);
    }
};