| 摘要 |
PROBLEM TO BE SOLVED: To refresh a memory without lowering the access efficiency while minimizing an increase of the circuit scale. SOLUTION: When a main block address MRAD held in a main refresh-address counter MRAC coincides with an access block address BAD corresponding to an access request, counter values are transmitted to a sub-refresh address counter SRAC. Then, the sub-refresh address counter SRAC operates in preference to the main refresh-address counter MRAC until reaching the final value. Thus, access and refresh operations can be simultaneously executed without interfering each other. As a result, it is possible to reduce the circuit scale and refresh the memory without lowering the access efficiency. COPYRIGHT: (C)2009,JPO&INPIT |
