学习如何控制蜂鸣器的声音输出，这次我们只输出一个频率的声音，试验使用的是交流蜂鸣器。我们的电路中用P17来驱动-Learn how to control the buzzer sound output, this time we only output one frequency sound, experimenting with the use of a communication buzzer. Our circuit using P17 to drive the
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