| 摘要 |
<p>PURPOSE:To form a microprocessor system which has low power consumption and the most appropriate processing speed by varying a clock frequency according to the purpose of control. CONSTITUTION:When a microprocessor circuit 1 in a stationary state wherein fast operation is not required, but only irreducible control is requested, a microprocessor 2 sends out a select signal to a selector circuit 6 to select the clock signal of the lowest frequency among the output signals of clock sources 5-1 - 5-n and operates at a slow speed with the selected clock signal. When an unstationary state is entered owing to the occurrence of a situation wherein fast operation is required, the microprocessor 2 sends out a select signal to the selector circuit 6 and performs situation processing with the most appropriate clock signal for the situation processing among the output signals of the clock sources 5-1 - 5-n. Consequently, the microprocessor need not operate at a clock frequency which is higher than required and carries out control wherein a necessary operation speed is obtained with low power consumption.</p> |
