A method and related apparatus used for controlling a peripheral device to transfer data to a bus. The peripheral device has a bus interface circuit and a controller. The method includes storing data outputted from the controller into a first storage block of the bus interface circuit, utilizing the bus interface circuit to simultaneously control the first storage block to output its stored data to the bus and control a second storage block of the bus interface circuit to store data outputted from the controller, and utilizing the bus interface circuit to control the second storage block to output its stored data to the bus.