About 20 years ago an 8-pin chip was available that contained a 3 NOTE DOORBELL. It required no other circuitry and consumed less than 1 microamp in the “waiting” state.
The chip connected to a small speaker and provided a very pleasant 3-note chime when the door-bell was pressed.
This chip was reasonably expensive when it cam out and the price rose extortionately until it was no longer viable to be added to a project.
In remembrance to this chip we have produced a program to simulate the 3-note chime and show how tones, notes and music can be produced by the PIC12F629 microcontroller.

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