| 摘要 |
PURPOSE:To make time for writing data in a storing section at each diagnosing and to perform diagnosing changing the number and position of bits freely conforming to the time of trouble by providing a data converting section for diagnosing between output of the storing section and an ECC checking circuit. CONSTITUTION:When diagnosing an ECC checking circuit, data arrive at a data converting section 18 for diagnosing from a storing section 1. At this time, when a TESE switch 18-a is made to SHORT state, DT is made to 1 by 1 bit, and latched to a DT input latch circuit 18-b, only the bit of data inputted to the ECC checking circuit 4 corresponding to the bit becomes inversion of output data of the storing section 1. By this operation, the ECC checking circuit 4 detects 1 bit error and outputs correction data while outputting a +1BE signal and outputs Hamming code and syndrome code over again. These are stored in a Hamming register 18 and a syndrome register 19, and it is possible to confirm which bit is detected as incorrect by the ECC checking circuit from these information.
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