| 摘要 |
PURPOSE:To enable the diagnosing of error correcting circuit and improve the reliability of a memory system by providing a special diagnosing route that can make direct memory access without passing through the error correcting circuit and reading and writing specified data or redundant bit information through the route or the error correcting circuit. CONSTITUTION:In diagnosing the error correcting function of an error correcting circuit, known data are written in a memory 1 through the error correcting circuit 2 (a). Then, only data in which an error is caused intentionally are written through a diagnosing route 41 (b). A processor reads the data through the error correcting circuit 2 (c) and by comparing with data written in (a) judges whether the error is corrected, i.e. whether error correcting function is normal or not (d). If correction is made normally, normal finishing is made (e) and if not, abnormal finishing is made (f). |
