Category Archives: Embedded Labs


Expanding the number of I/O lines using Microchip MCP23008

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A microcontroller comes with a limited number of general purpose input and output (GPIO) ports. However, some applications may require more ports than are available on the microcontroller. In such a case, GPIO expanders can be used to increase the I/O capability of the microcontroller. MCP23008 is one such device (manufactured by Microchip Technology) which provides an easy I/O expansion using 2-wire serial interface. This tutorial illustrates how to add an extra 8-bit I/O port to PIC12683 microcontroller (which has only 6 I/O pins) using MCP23008. A seven segment LED display and a tact switch will be connected to the

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Lab 12: Basics of LED dot matrix display

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We covered how to interface seven segment LED displays to a PIC microcontroller in two sections: Lab 6 and Lab 11. Today, we will move on to interfacing an LED dot matrix display. LED dot matrices are very popular means of displaying information as it allows both static and animated text and images. Perhaps, you have encountered them at gas stations displaying the gas prices, or in the public places and alongside highways, displaying advertisements on large dot matrix panels. In this experiment, we will discuss about the basic structure of a monochrome (single color) LED dot matrix and its

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Lab 11: Multiplexing seven segment LED displays

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In Lab 6, we discussed about interfacing a seven segment LED display to a PIC microcontroller. The seven segments were driven individually through separate I/O pins of the microcontroller. If we do just like that then for 4 seven segment LED displays, 28 I/O pins will be required, which is quite a bit of resources and is not affordable by mid-range PIC microcontrollers. That’s why a multiplexing technique is used for driving multiple seven segment displays. This tutorial shows how to multiplex 4 common anode type seven segment LED displays with a PIC16F628A microcontroller.

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Lab 10: DC motor interfacing to PICMicro

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Description Perhaps one of the most entertaining things to do with an embedded microcontroller is to get it to actually move something. Three very popular devices used to “make things move” include dc motors, RC servos, and stepper motors. This lab session will look at how you can interface a dc motor to a PIC microcontroller. Required Theory DC motors are simple two-lead, electrically controlled devices that convert electrical power into mechanical power through the interaction of two magnetic fields. One field is usually produced by a stationary permanent magnet (on the stator), and the other field is produced by

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Breadboard module for PIC16F628A

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Here’s another breadboard module that carries a PIC16F628A microcontroller. The power supply pins and the I/O ports of the PIC16F628A microcontroller are accessed through male headers. It can be easily plugged into a breadboard and is very useful for quick prototyping. It frees up a lot of space on the breadboard since the oscillator, reset, and ICSP circuits are already built on the module. It is different from the previous PIC16F688 breadboard module in the way that the microcontroller now runs with an external 4.0 MHz crystal. So, this module will be more appropriate for experiments that require accurate timing

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