Introduction - If you have any usage issues, please Google them yourself
1. Using a microcontroller timer, the output square waves with different frequencies through the IO port, in order to achieve different audio output signals, each song note timer initial value corresponding to the memory array or write. 2. IO port control microcontroller buzzer, when the square wave frequency is not pitch while buzzer is different, and a time delay duration beat programming using C language programming notation according to the buzzer playing music songs.