| 摘要 |
PURPOSE:To ensure free drawing of the fixed pattern at an optional position on the screen by installing the dot correspondence picture element memory of the pattern to be displayed at part of the CRT screen and then reading the memory based on the data disignating the start point, the end point plus the vertical and horizontal lengths of the pattern respectively. CONSTITUTION:Character code row signal SC equivalent to one line is sent to line buffer 3 from character memory 1 via the order of control circuit 2 to be stored temporarily, and then converted into the dot pattern signal indicating the character to be dilivered in the form of video signal VSC. On the other hand, the graphic display dot data stored previously in memory 5 is delivered as video signal Vsf of the pattern part by the order of control circuit 6. Signal Vsf is then mulitplied with signal VSC through multiplexer 7 and then transmitted to the CRT dispaly part. Circuit 6 disignates coordinate P of the display start point plus display length LX and LY to read out memory 5, thus the graphic dispaly part being set up. |
