| 摘要 |
<p>PURPOSE:To allow a microcomputer to change directly the operating frequency by providing a control circuit for changing the operating frequency and major components of an oscillating circuit in the inside of the microcomputer. CONSTITUTION:A circuit constituting the microcomputer is a complementary MOS(CMOS). The oscillating circuit 1 is oscillated by a lower frequency than the circuit 2 and the oscillation circuit 2 is oscillated with a frequency higher than that of the circuit 1. Then the transition to the low power consumption state takes place only when the stop signal is active. That is, a control circuit 3 makes the oscillation circuit 1 stopped at present time operative and waits until the oscillation is stabilized. Then one cycle of the oscillated waveform of the oscillation circuit 2 oscillated at present time is awaited for finish to stop the oscillation circuit. Then the oscillation circuit is changed from the circuit 2 to the circuit 1 in matching with the start of one cycle of the oscillation waveform of the oscillation circuit to change the operating frequency.</p> |
