Display control system for a scan type display apparatus

Claim 1

A display control system for a scanning type liquid crystal display apparatus in which a liquid crystal display screen is divided into a plurality of split display regions and respective display regions are simultaneously scanned in parallel, comprising: a dual port memory having a random access port and serial access port, display data being inputted through the random access port and outputted through the serial access port; a plurality of buffer memories, each buffer memory provided in correspondence to a respective split display region for memorizing portions of said display data corresponding to at least one raster of the split display region; means for generating display addresses to read out sequentially display data corresponding to each raster of every split display region one by one from said serial access port of said dual port memory to the buffer memories; an operating means for adding or subtracting an address value corresponding to a scroll value to or from the display addresses which access display data of a split display region to be scrolled during scrolling of the split display region; means for alternately storing the display data corresponding to each raster of the split display regions read out from said serial access port of said dual port memory into each of said buffer memories based on said display addresses; and means for simultaneously reading out the display data stored in said buffer memories for transferring said display data to said plurality of split display regions of said scanning type liquid crystal display apparatus.