Patent ID: 7576747

Claim:
A display controller, comprising: a display driver driving a display panel and to which image data is supplied from the display controller; a first memory storing image data and being accessed with a sequential access operation having a shorter access time per predetermined data unit than an access time of a random access operation; a second memory storing image data and consuming a less power than the first memory does at a time of the access operation; a first key color register in which a first key color data is set; a second key color register in which a second key color data is set; and a data transfer control part performing an image data transfer control between the first memory and the second memory, the data transfer control part performing a control to read out an image data from the first memory and write the image data in the second memory, an image processing being performed to the image data written in the second memory by the writing control, the data transfer control part performing a control to read out the image data that is rewritten in the second memory after the image processing from the second memory and to write the image data in the first memory, the image data written in the first memory by the data transfer control part or the image data stored in the second memory being supplied to the display driver, and the data transfer control part performing a control to write an image data of a pixel that is read out from the second memory and whose pixel value is inconsistent with the second key color data into the first memory.