The project intends to record and playback notes as well as some pre-recorded tunes by creating a synthesizer.
Explanation
A simple state machine is used for sectioning the multiple options of the synthesizer. The generation of the sine wave output will be interrupt driven since the main program would be the state machine. Since the state machine for the main program does not have to worry creating tones, a lot of freedom is given to the main program functions.
To convert the 8-bit PCM data into an analog, sinusoidal signal, the DAC0808 is used in the design of sin wave generation. The full range of PCM data can be outputted by the microcontroller and only the first 15 notes can be played by the synthesizer with additional op-amp.
The program involves the use of a state machine since the design allows the user to choose from several different playback options. The change of one state to another is done through the buttons on the proto-board. In order to play the notes of a song, the buttons that the user should hit are represented by the characters being displayed on the LCD.
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