Embedded Basics

What’s a Microcontroller?
A microcontroller (sometimes abbreviated µC, uC or MCU) is a computer-on-a-chip, or, if you prefer, a single-chip computer. Micro suggests that the device is small, and controller tells you that the device might be used to control objects, processes, or events. Another term to describe a microcontroller is embedded controller, because the microcontroller and its support circuits are often built into, or embedded in, the devices they control.

You can find microcontrollers in all kinds of things these days. Any device that measures, stores, controls, calculates, or displays information is a candidate for putting a microcontroller inside. The largest single use for microcontrollers is in automobiles—just about every car manufactured today includes at least one microcontroller for engine control, and often more to control additional systems in the car. In desktop computers, you can find microcontrollers inside keyboards, modems, printers, and other peripherals. In test equipment, microcontrollers make it easy to add features such as the ability to store measurements, to create  store user routines, and to display messages and waveforms. Consumer products that use microcontrollers include cameras, video recorders, compact-disk players, refrigerators, air conditioners and ovens. And these are just a few examples.
About 55% of all CPUs sold in the world are 8-bit microcontrollers and microprocessors.
A typical home in a developed country is likely to have only four general-purpose microprocessors but around three dozen microcontrollers. A typical mid-range automobile has as many as 30 or more microcontrollers.

Types of microcontrollers

As of 2008 there are several dozen microcontroller architectures and vendors including:

ARM core processors (many vendors) includes ARM9, ARM Cortex-A8, Sitara ARM Microprocessor
Atmel AVR (8-bit), AVR32 (32-bit), and AT91SAM (32-bit)
Cypress Semiconductor's M8C Core used in their PSoC (Programmable System-on-Chip)
Freescale ColdFire (32-bit) and S08 (8-bit)
Freescale 68HC11 (8-bit)
Intel 8051
Infineon: 8, 16, 32 Bit microcontrollers
MIPS
Microchip Technology PIC, (8-bit PIC16, PIC18, 16-bit dsPIC33 / PIC24), (32-bit PIC32)
NXP Semiconductors LPC1000, LPC2000, LPC3000, LPC4000 (32-bit), LPC900, LPC700 (8-bit)
Parallax Propeller
PowerPC ISE
Rabbit 2000 (8-bit)
Renesas RX, V850, Hitachi H8, Hitachi SuperH (32-bit), M16C (16-bit), RL78, R8C, 78K0/78K0R (8-bit)
Silicon Laboratories Pipelined 8-bit 8051 Microcontrollers and mixed-signal ARM-based 32-bit microcontrollers
STMicroelectronics STM8 (8-bit), ST10 (16-bit) and STM32 (32-bit)
Texas Instruments TI MSP430 (16-bit)
Toshiba TLCS-870 (8-bit/16-bit).
List of common MCU

1 INTRODUCTION

Beginners in electronics usually think that the microcontroller is the same as the microprocessor. That's not true. They differ from each other in many ways. The first and most important difference in favour of the microcontroller is its functionality. In order for the microprocessor to be used, other components, first of all memory, must be added to it. Even though it is considered a powerful computing machine, it is not capable of establishing direct communication with the peripherals. Instead, specialized circuits must be used for this purpose. This is how it was in the beginning and remains the same today.

On the other hand, the microcontroller is designed to be all of that in one. No other specialized peripheral components are needed for its operation as all necessary circuits, which otherwise belong to peripherals, have been already built into it. It saves both time and space required when designing a device.

2 NUMBERS

 Refer : Numbering System

3 DIGITAL ELECTRONICS

Refer : You must know this

At last, HOW TO MAKE THE RIGHT CHOICE?

OK, you are a beginner and you have made a decision to go on an adventure of working with microcontrollers. Congratulations on your choice. But, it is not as easy to choose the right microcontroller as it may seem. The problem is not a limited range of devices, but the opposite.
Before you start designing a microcontroller-based device, think of the following: how many inputs/outputs does your project require? Should it perform some other operations than to simply turn relays on/off? Does it need some specialized modules such as serial communication, A/D converter etc.? When you create a clear picture of what you need, the selection range is considerably reduced and it’s time to think of the price. Are you going to make several such devices? Several hundred? A million? Anyway, you get the point.
If you think of all these things for the very first time then everything seems a bit complicated. Make it simple and go step by step. First of all, select the manufacturer, i.e. the microcontroller family you can easily get. Study one particular model. Learn as much as you need, don’t go into details. Solve a specific problem and something incredible will happen- you will be able to handle any model belonging to that microcontroller family.

Remember learning to ride a bicycle. After several bruises you got when you started, you were able to keep the balance and then easily ride any other bicycle. And of course, you will never forget programming just as you will never forget riding bicycles!


References: www.mikroe.com
http://en.wikipedia.org/wiki/Microcontroller