Microcontroller - Engineering Notes

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Microcontroller

INTRODUCTION:
A microcontroller is a complete microprocessor system built on a single IC. Microcontrollers were developed to meet a need for microprocessors to be put into low cost products. Building a complete microprocessor system on a single chip substantially reduces the cost of building simple products, which use the microprocessor's power to implement their function, because the microprocessor is a natural way to implement many products. This means the idea of using a microprocessor for low cost products comes up often. But the typical 8-bit microprocessor based system, such as one using a Z80 and 8085 is expensive. Both 8085 and Z80 system need some additional circuits to make a microprocessor system. Each part carries costs of money. Even though a product design may require only very simple system, the parts needed to make this system as a low cost product.
To solve this problem microprocessor system is implemented with a single chip microcontroller. This could be called microcomputer, as all the major parts are in the IC. Most frequently they are called microcontroller because they are used to perform control functions.
The microcontroller contains full implementation of a standard microprocessor, ROM, RAM, I/0, clock, timers, and also serial ports. Microcontroller also called "system on a chip" or "single chip microprocessor system" or "computer on a chip".
A microcontroller 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.
Today microcontrollers are very commonly used in wide variety of intelligent products. For example most personal computers keyboards and implemented with a microcontroller. It replaces Scanning, Debouche, Matrix Decoding, and Serial transmission circuits. Many low cost products, such as Toys, Electric Drills, Microwave Ovens, VCR and a host of other consumer and industrial products are based on microcontrollers.

EVOLUTION OF MICROCONTROLLER:
Markets for microcontrollers can run into millions of units per application. At these volumes of the microcontrollers is a commodity items and must be optimized so that cost is at a minimum. Semiconductor manufacturers have produced a mind-numbing array of designs that would seem to meet almost any need. Some of the chips listed in this section are no longer regular production, most are current, and a few are best termed as "smoke ware" the dreams of an aggressive marketing department.

Application:
A microcontroller is a kind of miniature computer that you can find in all kinds of Gizmos. Some examples of common, every-day products that have microcontrollers are built-in. If it has buttons and a digital display, chances are it also has a programmable microcontroller brain.
Every-Day the devices used by ourselves that contain Microcontrollers. Try to make a list and counting how many devices and the events with microcontrollers you use in a typical day. Here are some examples: if your clock radio goes off, and you hit the snooze button a few times in the morning, the first thing you do in your day is interact with a microcontroller. Heating up some food in the microwave oven and making a call on a cell phone also involve operating microcontrollers. That's just the beginning. Here are a few more examples: Turning on the Television with a handheld remote, playing a hand held game, using a calculator, and checking your digital wrist watch. All those devices have microcontrollers inside them that interact with you. Consumer appliances aren't the only things that contain microcontrollers. Robots, machinery, aerospace designs and other high-tech devices are also built with microcontrollers.

TRENDS AND DEVELOPMENTS IN MICROCONTROLLER
The manner in which the use of microcontrollers is shaping our lives is breath taking. Today, this versatile device can be found in a variety of control applications. CVTs, VCRs, CD players, microwave ovens, and automotive engine systems are some of these.
A microcontroller unit (MCU) uses the microprocessor as its central processing unit (CPU) and incorporates memory, timing reference, I/O peripherals, etc on the same chip. Limited computational capabilities and enhanced I/O are special features.
The microcontroller is the most essential IC for continuous process-based applications in industries like chemical, refinery, pharmaceutical automobile, steel, and electrical, employing programmable logic systems (DCS). PLC and DCS thrive on the programmability of an MCU.
There are many MCU manufacturers. To understand and apply general concepts, it is necessary to study one type in detail. This specific knowledge can be used to understand similar features of other MCUs.
Microcontroller devices have many similarities. When you look at the differences, they are not so great either. Most common and popular MCUs are considered to be mature and well-established products, which have their individual adherents and devotees. There are a number of variants within each family to satisfy most memory, I/O, data conversion, and timing needs of end-user applications.
The MCU is designed to operate on application-oriented sensor data-for example, temperature and pressure of a blast furnace in an industrial process that is fed through its serial or operated on under the control of software and stored in ROM. Appropriate signals are fed via output ports to control external devices and systems.

APPLICATIONS OF MICROCONTROLLERS
Microcontrollers are designed for use in sophisticated real time applications such as
1. Industrial Control
2. Instrumentation and
3. Intelligent computer peripherals

They are used in industrial applications to control
• Motor
• Robotics
• Discrete and continuous process control
• In missile guidance and control
• In medical instrumentation
• Oscilloscopes
• Telecommunication
• Automobiles
• For Scanning a keyboard
• Driving an LCD
• For Frequency measurements
• Period Measurements