Chapter 3: The features of a microcontroller

What are the features that a microcontroller have? We know, a uC is a small computer which has almost everything built in a single chip. In this chapter we will learn about some of them by exploring a sample MCU. As we are going to use AVR microcontrollers, we will explore a general purpose model of AVR, named ATmega8.

A brief History
I will tell you some history now. Intel (Integrated Electronics) developed its first microprocessor chip 4004 in 1971 which was 4 bit. Intel opened the 8 bit market in 1974 when they released 8008 and 8080. During that time Motorola released its first one, 6800 which was also 8 bit.

Intel Corporation introduced 8051 series MCU in 1981. It was built according to the Harvard Architecture. It is referred to as the MCS-51 series. Many different vendors use this MCS-51 architecture originally developed by Intel.

Atmel Corporation introduced its first 8 bit Flash based microcontroller in 1994 which was a MCS-51 derivative. In 1996 Atmel released 8 bit AVR RISC microcontroller for the first time. Two students at the Norwegian Institute of Technology (NTH), Alf-Egil Bogen and Vegard Wollan conceived AVR which follows the Modified Harvard Architecture.

What does the term AVR stands for is not mentioned clearly. Many people think AVR stands for Alf Vegard RISC. From now on we will use the term AVR to refer to Atmel’s 8 bit AVR microcontrollers.

Microchip Technology has a popular series of uCs called PIC. If you want to know more about PICs, you can visit the Microchip Website.

The Architecture of AVR

The term RISC stands for Reduced Instruction Set Computing. The RISC processors are designed to run faster and provide better performance by using a reduced number of instructions.

Chapter 2: Embedded Systems

What is an Embedded System?

You may commonly encounter a term "Embedded System". Simply we can say, we use microcontrollers to build Embedded Systems. We will embed a MCU in a system which will perform our desired operation. Starting from digital watches and mp3 players up to traffic system controllers and Nuclear reactor controllers all are embedded systems. We already mentioned that the devices or the systems which require a computing brain can be implemented using microcontrollers.

The Steps to Build an Embedded System
Now we know the basics of a computer system. We can start designing our own embedded systems. The beauty of this work is that you can design

Chapter 1: The Basics

What is a Microcontroller?

The obvious question should be answered first. The word microcontroller is similar to the word microprocessor which is the core of modern computers.

Micro means something very small or tiny. The integrated circuits are fabricated in very small chips which have made our modern computers smaller.

Controller means something which has the ability to control. For example, deciding how much amount of heat to maintain in a microwave oven when it is set to run on auto cook modes or a worker robot which has to decide which box to put in which truck.

Figure: Two robot characters in the movie Wall E by Pixer Animation Studios.

Both the oven and the robot need some sort of thing which can make these decisions for them. Otherwise both of them are going to be useless. Another example can be a cell phone. It shows its battery level, warns us if the battery is low. When the charge is full, it tells us to

Introduction

A Microprocessor in a Motherboard

Dear Readers, welcome to my Microcontroller blog. I am a student of Electrical & Electronic Engineering at BUET. My intention here is to provide the basic concepts of Microcontrollers and a Beginners tutorial on how to program and use it. I am not a pro on this but I will try to help you out on the first steps. Only a few blogs or a few tutorials can’t teach you everything because