| 摘要 |
<p>PURPOSE:To make it possible to repeat data rewriting operation by several-ten times the performance of an EEPROM by dividing the contents of the EEPROM into N pages to manage the contents. CONSTITUTION:Data to be stored in one page 9 having capacity corresponding to 1/N the capacity of the EEPROM 8 and rewriting frequency are stored, and when a rewriting is requested, the rewriting frequency is counted by concentrically using a memory area 10 corresponding to the page and the count value is written in a rewriting frequency storing area in the same page. When the written frequency reaches the limit of rewriting frequency, the memory array of the PROM 8 is managed so that use of the page concerned is stopped and the succeeding page is used. When the final page N divided into N pages and managed reaches the limit of rewriting frequency, the service life of the memory is discriminated.</p> |
