| 摘要 |
PURPOSE:To easily perform data transfer between a read-only memory and a writable memory, by invalidating a readout signal and informing the fact to the outside the output of an FF by reseting the FF, and enabling read and write to be performed by setting the FF. CONSTITUTION:In a semiconductor memory device, a reset generation circuit 9 is operated and a counter 8 and a RSFF10 are reset by applying a supplying power source. The output of th eFF10 is supplied to the output terminal 10 of a memory control signal via a buffer 11, and also, it is inputted to a gate 7, and the gate 7 invalildiates the readout signal appearing on a readout control terminal. Meanwhile, when the inputs of a memory selection input terminal 1 and a write control terminal 2 go to low levels, the output of a gate 6 goes to a high level, and a carry signal 19 is outputted from the counter 8 by the output of the gate 6, then, the FF10 is reset, and the gate 7 is activated. During a time until the signal 19 is outputted after the counter 8 is reset, a readout request is prohibited, and since a signal of high level appears from a terminal 12, it is possible to recognize the fact fro the outside.
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