Patent ID: 6927776

Claim:
A data transfer device for transferring data between a local memory and a system bus, the local memory having a frame buffer region for storing pixels at addresses associated with coordinates of the pixels and a general region occupying the remaining area of the local memory, the data transfer device comprising: an interface section for generating a transfer parameter for accessing one of the frame buffer region and the general region based on control data for controlling data transfer sent from the system bus and outputting the generated transfer parameter, in addition to transferring data to/from the system bus; and a data processor for generating an address of data to be transferred in the local memory according to the transfer parameter and transferring data to/from the local memory using the generated address, in addition to transferring data to/from the interface section, wherein the interface section further comprises: a data buffer for storing data received from one of the system bus and the data processor, and outputting the data to the other of the system bus and the data processor not providing said data; a control register for storing the control data; and a transfer parameter generator for generating the transfer parameter based on the control data stored in the control register and outputting the generated transfer parameter, the transfer parameter generator also controlling the data buffer, an address information register for storing an address designating the general region; and an address comparator for comparing the address stored in the address information register with an address designating an access destination sent from the system bus, and outputting the comparison result, wherein the transfer parameter generator generates a parameter for accessing the general region as the transfer parameter when the comparison result indicates that the address designating the access destination is an address in the general region, and outputs the generated parameter.