The present invention relates to a display control device and a data processing unit using the same, and a technique useful in application to a communication portable terminal device having a liquid crystal controller driver.
A liquid crystal controller driver performs control for writing display data supplied from a host device into a frame buffer memory out of synchronization with its internal operation timing, for reading display data written into the frame buffer memory in synchronization with the internal operation timing, and for driving signal electrodes of a liquid crystal panel while using the read display data to synchronize with the timing of display. In Japanese Unexamined Patent Publication No. JP-A-2003-131622, there is description about a technique for display data compression and storing on a frame buffer memory with the aim of increasing the CPU throughput required for write and read of display data on the frame buffer memory. Specifically, iterations of image data in display data are counted in units of pixels, and the top of the iterations and the number thereof are stored in combination as information of iteration. Then, using the information of iteration in reading display data, the readout of image data iterated can be omitted.