| 摘要 |
PROBLEM TO BE SOLVED: To make control of a semiconductor memory by a controller easy in an electronic device mounting a semiconductor memory requiring refresh to hold data such as DRAM(dynamic random access memory) and a controller. SOLUTION: A DRAM 1 is constituted so that refresh is controlled by itself, at the time of a refresh period, a busy signal BUSH1 is outputted to a BUSY1 signal line 4, and a refresh address is generated inside and refresh is performed, when refresh is finished, a BUSY1 signal is removed, a controller 2 is constituted so that when a busy signal BUSY1 outputted to the BUSY1 signal line 4 from the DRAM1 is received, access for the DRAM1 is stopped until a busy signal BUSY1 is removed.
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