| 摘要 |
<p>PURPOSE:To reduce the quantity of hardware remarkably by making the inhibition of writing to PROM for which writing is completed by adding a signal corresponding to data stored at the time of erasing to data pin of EPRPM. CONSTITUTION:The operations of writing and reading of data are made repeatedly on an observed address designated by the address signals of EPROM 1A, 1B... under the control of a controlling section 10. Judging of completion of writing of each EPROM is made by the controlling section 10 basing on the output of comparators 8A, 8B... at the time of every reading. The controlling section 10 controls drivers 6A, 6B... corresponding to EPROM judged as the completion of writing to the state of high impedance. Thereby, the data pin of EPROM corresponding to the drivers is kept at VR potential and the writing operation thereafter is inhibited. Thus, the hardware can be reduced remarkably.</p> |
