| 摘要 |
<p>PURPOSE:To prevent the erroneous operation due to noise, etc., by setting the write-in mode voltage sufficiently higher than the power source voltage, lowering the voltage and applying it to the memory as the write-in voltage. CONSTITUTION:In the write-in, the power source voltage VCC (for example 3V) is applied on a memory cell group 1 and the write-in mode discrimination voltage VPPM (for example 13V) higher than the set voltage 12.5V is applied on the write-in control circuit 10 and the output enable signal OE is made 'H'. The address and data to write-in are input in buses 6, 7 respectively. Next the circuit 10 lowers the VPPM to a specified write-in voltage VPP; 5 volts, then applies it to the memory cell 1. In this state, the chip enable signal CE is made 'L', then the write-in signal WR becomes 'L' the read-out signal RD 'H' and the write-in is conducted. In the read-out, WR is made 'H' RD 'L' and the data at a specified address is output in the data bus 7. Thus the power source voltage VCC is made higher and the erroneous operation is prevented.</p> |
