module Drv {
    interface Gpio {
        @ Port used to write to a GPIO pin
        sync input port gpioWrite: Drv.GpioWrite

        @ Port used to read from a GPIO pin
        sync input port gpioRead: Drv.GpioRead

        @ Port used to indicate transition on the GPIO pin
        output port gpioInterrupt: Svc.Cycle
    }
}