JPS5454011A - Magnetic memory control device - Google Patents

Abstract

PURPOSE: To prevent block information other than that designated from being broken by inhibiting the production of the writing allowing signals in response to the time-over signals which are generated by such a time monitoring circuit as is reset upon every writing operation of one word.

CONSTITUTION: In response to writing command signals from a processing device, the reading/writing control circuit 3 of a control station 1 generates write signals so that the output of a NOR gate 9 becomes the writing allowing signals. At the same time, a time monitoring circuit 7, which is released from its reset condition in response to the write signals, and a bit counter 4 count the writing clocks generated by a timing circuit 2 so that the circuit 7 is reset in response to information transfer signals REQ which are generated upon the counting operation of one word of the counter 4. In case there is no signals REQ generated from the counter 4 due to a disorder, the circuit 7 becomes overoutned to generate time-over signals, an FF 8 is set so invert the output of the gate 9 so that the writing operation is prohibited. As a result, the record at a portion other than the designated block can be prevent from being broken due to runaway

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