| 摘要 |
In a microcomputer internally comprising a circuit including a CPU and operating in synchronism with an internal clock signal, and an OSD controller operating in synchronism with the internal clock signal and an external horizontal synchronous signal, an oscillation circuit is coupled to an external oscillator, for generating the internal clock signal used in common to the circuit and the OSD controller. An oscillation control circuitry receives the horizontal synchronous signal for generating a CPU stop request signal to the circuit before supply of each horizontal synchronous signal, so that the circuit generates a CPU stop signal after a stopping processing is completed. When the oscillation control circuitry receives the CPU stop signal, the oscillation control circuitry causes the oscillation circuit to stop generation of the internal clock signal. Thereafter, in response to each horizontal synchronous signal, the oscillation control circuitry causes the oscillation circuit to restart the generation of the internal clock signal. As a result, the internal clock signal is generated in synchronism with the horizontal synchronous signal.
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