| 摘要 |
<p>PURPOSE:To improve the reliability of a ROM by generating an error correcting check bit in the internal part of the ROM and writing the bit together with external data at writing time and executing error correction processing and making a writing circuit into an inactive state for byte writing at reading out time. CONSTITUTION:When the leading address and the data of a write page are set, and a latch mode is started, the data are taken in a page data latch 5. Next, when a writing command signal is given, the check bit is generated and added to the data of the latch 5 by an error correcting and coding circuit 8, the data and the check bit are given to a memory cell 1 and a checking memory cell 10, and writing is executed. At reading out time, corresponding data of the memories 1 and 10 are read out, error-corrected by an error correcting and decoding circuit 9, and after that outputted to an external part. Further, for the byte writing, internal writing is never executed, and a program circuit 7 is made into a non-operating state. Thus, the memory, which prevents wasteful writing and has the high reliability, can be obtained.</p> |
