| 摘要 |
<p>PROBLEM TO BE SOLVED: To enable low-power-consumption operation by providing a low-speed operation memory which stores a low-speed mode program and read with program addresses within a specific range and also providing a memory operation control means which outputs a high-speed operation stop signal for low-speed operation. SOLUTION: When high-speed operation is processed, a high-speed ROM 11 is used and a program is read out of addresses 000000H to 18000H to perform a specific process. Then when the high-speed operation is changed to the low- power-consumption operation, 0 is written in an operation mode setting register and an operation mode signal M is held at level L to vary the frequency of a clock CK. Then branching to a low-speed ROM 12 after the address 18000H is performed. Then a memory controller 3 which is monitoring the value of an address A judges that the low-power-consumption mode is entered, and holds an operation indication signal E at level L and supplies it to a high-speed ROM 11, thereby stopping supplying the electric power to the high-speed ROM 11.</p> |
