| 摘要 |
PURPOSE:To diagnose the error correcting and detecting circuit of a storage device, by providing a means which generates an error in a specified bit and causing the error correcting and detecting circuit to correct or detect the generated error. CONSTITUTION:When a diagnosis is executed, a diagnostic mode discriminating section 5 is set to the diagnostic mode and a switching signal 7 also designates the diagnostic mode. Stored data information sent to a main storage device is received by a data transmitting/receiving section 3 and stored data bits are sent to an erroneous pattern generating section 6 after redundant bits for correcting and detecting error are to the bits at an error correcting and detecting circuit 4. Since the signal 7 designates the diagnostic mode, the stored data information is written in a memory section 2 after the information is converted into an erroneous data pattern in which errors are generated in specified bits at the erroneous pattern generating section 6. The erroneous data pattern is read out by software and subjected to 1-bit error correction and 2-bit error detection at the error correcting and detecting circuit 4, and then, stored in a diagnosed result holding section 8. By reading out the storing content of the holding section 8, it can be discriminated whether the operation of the circuit 4 is normal or not. |
