| 摘要 |
PURPOSE:To decrease the number of the circuit elements as well as increase the memory using efficiency, by putting both the dynamic RAM's refresh and the reading means into one unit and then carrying out both the reading and the refresh action at one time. CONSTITUTION:The CPU1 gives the memory request to memory control part 3 and then delivers the address after the request is accepted. And CPT2 gives the memory use periodically to part 3 for display. Thus dynamic RAM4 receives the access by both CPU1 and CPT2 each. When the address value is given to the address line, RAM4 gives refresh to all corresponding ROW or COLUMN. And the next refresh request is given after about 2ms. On the other hand, the scanning time is about 64mus for one raster of the noemal display unit, and thus the addressing can be given to RAM4 with raster 12 after raster 0. And the data which are read with raster 0 and stored in the buffer can be used for rasters 1-11. As a result, the number of the circuit elements can be reduced, at the same time increasing the using efficiency of the memory. |
