Add more I/O ports to PIC12F683 with MCP23008 port expander

PIC12F683 microcontroller has got only 6 I/O pins. We saw how to interface a standard character LCD to PIC12F683 using a 74HC595 shift register. The same technique can be implemented for interfacing a seven segment LED display. However, shift registers like 74HC595 allows to add more output ports but not any input port. MCP23008 is a GPIO port expander that can provide additional 8 port pins that can be configured as digital inputs or outputs. This tutorial describes all the details about using MCP23008 with PIC12F683 to expand its I/O capability.

Experiment No. 7: Generating Melody with a Microcontroller

Introduction
This experiment is about generating a melody tune using a PIC microcontroller. Well, this won't be difficult if you know the notes of the tune, and their respective frequencies. Here's a chart for note to frequency conversion. We will play the 'Happy Birthday' tune with a PIC12F683 microcontroller. The microcontroller will generate the frequencies of the various notes (with proper timing) in the tune and the melody will be played in a piezoelectric buzzer.

Circuit Setup
The piezo buzzer is connected to the GP2 port of PIC12F683.

Contact-less tachometer based on PIC16F628A uC

Check out my new tachometer project based on PIC16F628A microcontroller. It uses an infrared sensor module to sense the rotation speed of a shaft or disc. The range of measurement is 0-9999 RPM. The full details on hardware and software is available.