| 摘要 |
<p>PURPOSE:To eliminate excess writing, erasing by omitting writing of writing to erasing of an auto erasing function when all bit '0' is decided in a data block. CONSTITUTION:When an output 29 of all '1' deciding latch 8b is an H level, data ''0'' is written at the time of writing all '0' to reading as usual in the case of auto erasing, but even in this case, if an output of the latch 8b is an L level, writing is not executed. An erasing circuit does not output a high potential to a source line, and does not erase in the block. Thus, the output 29 of the latch 8b skips all '0' writing to erasing cycle at the time of an L level. When an output 40 of all '0' deciding latch 8a is an H level, a writing circuit writes ''0'' at the time of writing cycle in the case of the auto erasing, but does not write even in the case of all '0' writing cycle at the time of L level, and erasing is merely executed.</p> |
