| 摘要 |
PURPOSE:To simplify the constitution of a refresh control circuit to improve the mounting efficiency of a memory and to reduce the cost of the memory part by providing one channel of a direct memory access controller (DMAC) only for refresh. CONSTITUTION:In a system having a dynamic RAM 3 requiring memory refresh and a DMAC 20, one channel of the DMAC 20 is provided only for refresh. A RAM control part 2 does not especially use a refresh control circuit but uses only a memory access control circuit, and the memory read cycle is used for refresh. That is, data is transferred from one memory address to another through the DMAC 20 to attain the refresh effect. Since the function of the refresh control circuit is performed by the DMAC 20 in this manner, the constitution of the refresh control circuit is simplified to improve the mounting efficiency of the memory and the cost of the memory part is reduced. |
