| 摘要 |
<p>PURPOSE:To prevent a writing to an EPROM from being too deep by prohibiting the writing of data when the read data coincides with the written data. CONSTITUTION:One pulse writing signal generators 15a, 15b are disposed correspondingly to the EPROMs 1a, 1b to write the written data to the EPROMs 1a, 1b. The generators 15a, 15b prohibit the writing thereafter when the data read by OR circuits 16a, 16b coincides with the written data, and writes the written data as it is when they do not coincide. Additional writing pulse generating circuits 17a, 17b execute an additional writing according to the number of writing the one pulse of the EPROMs 1a, 1b. Thereby, the depth of the writing is not excessive but limited to a fixed range.</p> |
