| 摘要 |
<p>PURPOSE:To decrease power consumption without lowering a ROM access speed by dividing ROM circuit constitution into plural blocks and executing partially the precharging. CONSTITUTION:A ROM address MSB signal inputted from an input terminal 6 is fetched into an address latch circuit 1 by the latch clock signal of an input terminal 5. In case the ROM address MSB signal is a high level, the signal to make active a ROM address=high side precharging circuit 2 from an address latch circuit 1 is generated from an address latch circuit 1, in synchronism with the clock signal for precharging of an input terminal 4 and the precharging signal is outputted from the high side precharging circuit 2. Reversely, the active signal is not generated to a ROM address=low side precharging circuit 3 and the precharging signal is not outputted fro the circuit 3. In case the ROM address MSB signal is a low level, the precharging signal is outputted from the circuit 3 and not outputted from the circuit 2.</p> |
