Abstract: When transferring digital signals between plural electronic devices, there is a case of transferring data differing in the number of bits using the same structure. In this case, plural kinds of structure corresponding to the number of the bits are needed, and the apparatus becomes large and complicated. The data transfer apparatus of the present invention is capable of transferring data differing in the number of bits easily using the same structure, by the efficient use of constituent elements in every aspect of data transfer and processing and time sharing techniques.

Abstract: A data transfer apparatus transfers serial data to and from a controller. The apparatus includes a first memory which stores at least one of command data and address data of the serial data transferred from the controller, and a second memory which stores a main body portion of the serial data to be transferred to and from the controller. Changeover circuitry is provided which selectively applies the serial data transferred from the controller to either the first memory or the second memory. Further, the changeover circuitry applies a clock signal received from the controller to one of the first memory or the second memory in accordance with a latch signal received from the controller. The second memory functions to selectively store the main data portion of the serial data received from the controller and to read the main data portion of the serial data transmitted to the controller.