PIC18F | Embedded Lab

Category Archives: PIC18F

Lab 14: Inter-Integrated Circuit (I2C) communication

Posted on May 9, 2011 by R-B 34 comments

I2C (Inter-Integrated Circuit) is a short distance serial interface that requires only 2 bus lines for data transfer. It was invented by Philips in 1980’s, originally to provide easy on-board communications between a CPU and various peripheral chips in a TV set. Today, it is widely used in varieties of embedded systems to connect low speed peripherals (external EEPROMs, digital sensors, LCD drivers, etc) to the main controller. In this experiment, we will cover an overview of I2C protocol, its implementation in PIC microcontrollers, and the method of connecting single and multiple devices on a common I2C bus. We will

Lab 12: Basics of LED dot matrix display

Posted on April 28, 2011 by R-B 49 comments

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

How to make a contact-less digital tachometer using IR-light reflection technique

Posted on April 21, 2011 by R-B 41 comments

Tachometer is a device that measures the rotational speed of any shaft or disc. The unit of the measurement is usually revolutions per minute or RPM. The traditional method of measuring RPM of a rotating shaft was based on velocity feedback concept where a dc generator is hooked to the rotating shaft so that the voltage induced across the generator’s terminals is proportional to the speed of the shaft. Today, we are going to make a digital tachometer based on a PIC microcontroller that requires no physical contact with the rotating shaft to measure its rotational speed. The physical contact

Getting started with PIC18F Microcontrollers

Posted on April 6, 2011 by R-B 14 comments

After writing quite a bit of experimental tutorials on PIC16F series of microcontrollers, I thought of moving forward to the enhanced-range family of PIC microcontrollers, the PIC18F, which was introduced by Microchip in late 90s. Although PIC16F series are excellent general purpose microcontrollers, certain limitations have emerged, such as, they have limited program and data memory, their stack size is small, and all the interrupt sources have to share a single interrupt vector. Their limited instruction set also doesn’t provide direct support for more advanced peripherals interfaces like USB and CAN. The basis of the PIC18F Series is to address