Networking of multiple microcontrollers

Networking of Multiple Microcontrollers

Networking of Multiple Microcontrollers Introduction ďƒ˜ The project is designed to demonstrate how multiple microcontrollers can be connected in a network to achieve the desired output. More and more microcontrollers are embedded in different kinds of products from industrial environment to domestic area; a good example is the automobile sector. A modern day car has number of microcontrollers integrated within its system.

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Networking of Multiple Microcontrollers Block Diagram

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Networking of Multiple Microcontrollers Hardware Requirements            

8051 series Microcontrollers Keypad LCD Relay Transformer Diodes LED Resistors Capacitors Regulator Buzzer Lamp http://www.edgefxkits.com/

Networking of Multiple Microcontrollers Software Requirements  Keil compiler  Language: Embedded C or Assembly

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Networking of Multiple Microcontrollers Communications and Networks  Data Communications • Transmission of signals • Encoding, interfacing, signal integrity, multiplexing etc.  Networking • Topology & architecture used to interconnect devices

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Networking of Multiple Microcontrollers Network Trends Voice, Image, Data, Video

Microcontroller Microcontroller

Networking

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Networking of Multiple Microcontrollers Communication Systems  Process describing transfer of information, data, instructions between one or more systems through some media.

Examples: • People, computers, cell phones, etc.

• Computer communication systems  Receivers and transmitters: Desktop computers, mainframe computers, etc.

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Networking of Multiple Microcontrollers Communication Systems  Signals passing through the communication channel can be Digital, or analog.

• Analog signals: continuous electrical waves.

• Digital signals: individual electrical pulses (bits) Communication channel

RX

TX

RX RX

Amp/Adaptor

Communication media

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Networking of Multiple Microcontrollers Working Principle ďƒ˜ The networking and communication between them becomes necessary. ďƒ˜ The importance of having multiple microcontrollers against a single one is if one of the microcontrollers goes bad only the function related to that particular microcontroller will be affected.

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Networking of Multiple Microcontrollers Working Principle  The project demonstrates a command based monitoring tool using the RS232 protocol.  A network of three microcontrollers is used in this project.  The first one is connected to a keypad for input action.  The second one is connected to an LCD display and the third one to drive a relay for controlling any load (LAMP).

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Networking of Multiple Microcontrollers Working Principle  Input takes a password on the first MC to display it on the second MC while the third one executes the output only if the password is right.  Wrong password if entered will generate a buzzer sound.  Though this task can be performed by a single microcontroller.  The project uses multiple microcontrollers to explain the concept of networking.

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Networking of Multiple Microcontrollers Working Principle  It is practically impossible by a single microcontroller to handle input action, display and output which are located way apart.  The system uses a combination of three microcontrollers for this purpose.

• One is used to operate the load.

•

second one is used to display output on LCD display .

• The third one is used to take user input through a keypad.

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Networking of Multiple Microcontrollers Working Principle  Consider a situation which requires 15 connections for a display unit from microcontroller, and 7 connections from keypad.  So instead of using single microprocessor and multicore cables for kilometers.  We use a single cable and more microcontrollers to simplify the working and reduce costs.

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Networking of Multiple Microcontrollers MICROCONTROLLER  It is a smaller computer  Has on-chip RAM, ROM, I/O ports. etc..

CPU

I/O Port

RAM ROM Serial Timer COM Port

A single chip Microcontroller

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Networking of Multiple Microcontrollers INTERNAL STRUCTURE OF A MICRO CONTROLLER

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Networking of Multiple Microcontrollers Multi Microcontroller Networking System ďƒ˜ Our system aims at connecting and coordinating multiple microcontrollers in order to achieve the desired output. ďƒ˜ Increasing number of microcontrollers are used these days for various industrial and domestic applications.

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Networking of Multiple Microcontrollers Designing The Communications Microcontroller Microcontrollers • Main Microcontroller: i.MX31 from Freescale • Communications Microcontroller: LPC2194/01 from NXP • Low Level Microcontroller: LPC2194/01 from NXP

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Networking of Multiple Microcontrollers Communication Protocols • Main to Communications Full Speed USB • Communications to Low Level CAN Bus

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Networking of Multiple Microcontrollers Power Supply  A DC Power Supply Unit (commonly called a PSU) deriving power from the AC mains (line) supply performs a number of tasks: •

It changes (in most cases reduces) the level of supply to a value suitable for driving the load circuit.

•

It produces a DC supply from the mains (or line) supply AC sine wave.

•

It prevents any AC from appearing at the supply output.

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Networking of Multiple Microcontrollers Parts of a Power Supply  The output voltage is kept at a constant level, independent of changes in: •

The AC supply voltage at the supply input.

•

The Load current drawn from the supply output.

•

Temperature.

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Networking of Multiple Microcontrollers Power Supply

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Networking of Multiple Microcontrollers Relay  It is a electro magnetic switch.  Used to control the electrical devices.  Copper core magnetic flux plays main role here.

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Networking of Multiple Microcontrollers Relay  The relay's switch connections are usually labeled COM, NC and NO:  COM = Common, always connect to this; it is the moving part of the itch.  NC = Normally Closed, COM is connected to this when the relay coil is off.  NO = Normally Open, COM is connected to this when the relay coil is on .

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Networking of Multiple Microcontrollers BC547 (NPN –Transistor)  The BC547 transistor is an NPN Epitaxial Silicon Transistor.  It is used in general-purpose switching and amplification BC847/BC547 series 45 V, 100 mA NPN general-purpose transistors.

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Networking of Multiple Microcontrollers BC547 (NPN –Transistor)  The ratio of two currents (Ic/Ib) is called the DC Current Gain of the device and is given the symbol of hfe or nowadays Beta, (β).

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Networking of Multiple Microcontrollers BC547 (NPN –Transistor)  The current gain from the emitter to the collector terminal, Ic/Ie, is called Alpha, (α), and is a function of the transistor itself.

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Networking of Multiple Microcontrollers Liquid Crystal Display (LCD)  Most common LCDs connected to the microcontrollers are 16x2 and 20x2 displays.  This means 16 characters per line by 2 lines and 20 characters per line by 2 lines, respectively.  The standard is referred to as HD44780U.  It refers to the controller chip which receives data from an external source (and communicates directly with the LCD.

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Networking of Multiple Microcontrollers Liquid Crystal Display (LCD) ďƒ˜ If an 8-bit data bus is used the LCD will require 11 data lines (3 control lines plus the 8 lines for the data bus). ďƒ˜ The three control lines are referred to as EN, RS, and RW.

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Networking of Multiple Microcontrollers Liquid Crystal Display (LCD) Diagram

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Networking of Multiple Microcontrollers Application ďƒ˜ This technology is widely used in modern automobiles.

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Networking of Multiple Microcontrollers Future Enhancement ďƒ˜ This project being based on serial communication can be enhanced by using wireless communication among the controllers by avoiding costly cabling.

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Networking of Multiple Microcontrollers Conclusion ďƒ˜ We have learned how multiple microcontrollers can be connected in a simple networking system to get the desired output. These type of networking of multiple microcontrollers are used in many areas like industrial and domestic areas.

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