| 摘要 |
PURPOSE:To utilize effectively a memory device having defection, by enabling an error within a permissible limit to be processed continuously by providing an error frequency counting means and comparing means. CONSTITUTION:An error signal outputted from read control circuit 3 is inputted to error control circuit 5. At time 1 in the figure, counter 30 of circuit 5 is reset. Next, as the error signal is generated once at some time 2 corresponding to the occurrence of a read error, the value of counter 30 becomes ''1''. Similarly, the error signal is outputted (n) times up to a certain time and counter 30 goes up to (n); if it is greater than error permissible frequency N held in constant holding register 31 of circuit 5, comparing circuit 32 outputs an error over signal. On the other hand, if N is greater than (n), namely, if it is within the error-occurrence permissible limit, counter 30 is reset with the output signal of timer 4 at time 3 in the figure and repeats the said operation again. In this case, no error over signal is generated, so that the data processing will be continued. |
