| 摘要 |
<p>PURPOSE:To simplify device constitution and to reduce cost by storing previously data indicating a specific display area and a display end position in an area setting memory and reading it in synchronism with the writing operation of a frame memory, and writing display area data in the frame memory and inhibiting display end position data from being written. CONSTITUTION:At the time of video data is written in the frame memory 5, the display end position is detected and position information for inhibiting data from being written is stored previously in the area setting memory 16. Then, the address of the memory 16 is specified from a scan converter 8 in synchronism with the writing of the video data to the frame memory 5 to read the storage contents, which are supplied to an end position detecting circuit 17. The end position detecting circuit 17 when detecting data '1' on an azimuth ring 18 from the area setting memory 16 outputs a write inhibiting signal to a scan converter 8 to inhibit data from writing a memory area exceeding the azimuth ring 18.</p> |
