| 摘要 |
PURPOSE:To recognize the normality of conversion data by using a conversion code for making an odd number parity formed from data before the conversion and the odd number parity formed from data after the conversion exclusive as a condition for code converting the data of n bits into the data of n+1 bits. CONSTITUTION:In an exclusive OR circuit 19, the exclusive OR of the applied odd number parity is taken, when the parities coincide, an error signal 27 indicating that the code conversion in a 8-9 conversion circuit 13 is erroneous is outputted. This error signal 27 is informed to a host device, for instance, a CPU 2 and the data at the part is written again or corrected by a correction circuit 9 or the like. Further, in a counting circuit 20, the output of an odd number parity generation circuit 18 is counted every n+1 byte according to a control signal 26 given from a control circuit 16 and when the number of 1 is an even number, an error signal 21 is outputted and informed to the CPU 2 or the like. Thereby, the normality of a correct code conversion is checked.
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