PICTURE DATA PROCESSING UNIT FOR PICTURE DISPLAY DEVICE

摘要

PURPOSE:To improve picture display speed and to make a displayed picture stable by executing read and update of picture data between 1st and 2nd picture data storage means alternately in parallel. CONSTITUTION:A graphic RAM rewrite signal C2 is inputted to a rewrite controller 24 from a CPU 10. The control signal C2 is a 6-bit signal, and its 2-bit each corresponds to a write/read/delete command to 1st-3rd multi-port RAMs 21-23 respectively. The rewrite controller 24 controls the write/read/delete of the 1st-3rd multi-port RAMs 21-23. An output from the 1st-3rd multi-port RAMs 21-23 is selectively given to a picture composite circuit 27 via a switching circuit 26. The composite picture by the circuit 27 is displayed on a CRT 5. Furthermore, the circuit 26 is selected by the graphic RAM rewrite signal C2 from the CPU 10.