| 摘要 |
<p>PURPOSE:To decrease the writing time of a PROM writing device, by providing a circuit to decide whether or not all units of the writing data should be written and a circuit that controls the writing cycle through the above-mentioned deciding circuit. CONSTITUTION:The initial state of an unwritten PROM is referred to as 00H to be used as a word which is not necessary to be written. An address is fed at t1, and then the writing data is fed at t3 respectively. When the writing data is in the state 00H requiring no writing, the need of writing is decided by a data deciding circuit and with the timing of phi3. No writing signal of phi4 is produced in the state 00H, and a control signal of phi3 is produced. Then a word process is over, and the RATE signal phi1 is produced to proceed to the next address. In such way, the total writing time can be reduced.</p> |
