JPS5597654A - Fault record control system - Google Patents

Abstract

PURPOSE: To secure recording for the internal state before detection of the error by counting the clock number at the retrial time and thus discontinuing the clock right before detection of the error.

CONSTITUTION: With detection of the error, error detection latch 10 is turned on. Thus clock counter 50 is reset, and at the same time the first internal state is scanned out. In case the error can be rewritten, switch 20 is turned on for the first retrial to renew retrial counter 30 with gates G₂ and G₄ opened. Then counter 50 counts the clock number until the retrial is succeeded. When the count number is n and the error factor is identical, the retrial counter is renewed for the 2nd retrial. Thus gate G₃ opens, and counting is given to counter 50 by -1 via the clock pulse under retrial. And when the count value becomes in agreement with the value of clock stop number register 40, i.e., before detection of the error, the clock stop indication is given by the output of comparator 60. At the same time, the scan-out is given to the internal state which is preceding the error detection by K-clock.

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