embedded system Industrial Training

SIX WEEKS INDUSTRIAL TRAINING REPORT Submitted for partial fulfillment of award of

BACHELOR OF ELECTRONICS & COMMUNICATION ENGINEERING I.E.T. BHADDHAL (ROPAR)

Submitted by:

Shivinder singh Uni.Roll No:617041617 College Roll No: EC05L5437 3rd Year ECE

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CONTENTS 1) Company profile 2) PCB Designing  Functions of PCB  Classifications of PCBs  Technique used for PCB design  PCB design software 3) OrCad design environment  PCB design steps in OrCad i. Entry to schematic ii. Creating Netlist  Placement of Layout Plus  Setting board parameters  Creating board outline  Placement of components  Conductor routing  Design rule check  Post processing 4) Power system design  Unregulated power supplies  Regulated power supplies  Bench supply diagram 5) Embedded Systems  What is Embedded System  Applications  Difference between microprocessor & micro controller 2

 Types of microcontroller Architectures  Difference between CISC & RISC  History of 8051  8051 core architecture  Pin description of 8051  Atmel’s AT89S8252 microcontroller  Feature of AT89S8252  Pin description of AT89S8252  Hardware interfacing & programming using AT89S8252  Software used for Embedded system design using MCS-51 family  Advantage of Embedded C over Assembly language programming  Interfacing o LED interfacing o LCD interfacing o Seven Segment Display Interfacing o ADC interfacing o Relay Interfacing o Matrix Keyboard Interfacing o Serial communication [b/w PC & Microcontroller] o Hardware interrupt programming

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ACKNOWLEDGEMENT

First of all I would like to thank almighty GOD who has given this wonderful gift of life to us. He is the one who is guiding us in right direction to follow noble path of humanity. In my six months industrial training it is a wonderful experience to be a part of NETMAX TECHNOLOGIES where I have opportunity to work under brilliant minds. I owe my deep regards for the supporting and kind staff authorities who are helping me in my lean patches during these six months. The knowledge I am gaining throughout my studies have the practical implementation during this period. I am grateful to all the staff of NETMAX and for their timely support and sharing of their experience with me. I would like to express my heartiest concern for Mr. ROHIT KHOSLA for his able guidance and for his inspiring attitude, praiseworthy attitude and honest support. Not to forget the pain staking efforts of our college training and placement cell and specially my training and placement officer Mr. Charanjeet Singh. Last but not the least I would express my utmost regards for the electronics and communication department of our Institute.

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COMPANY PROFILE Netmax Technologies is an organization which is established in the field of Network Support, Network training and Embedded systems. It provides support and training in the field of networking solutions (CISCO, LINUX) and embedded systems (Micro controller based design, Electronics system design). In Education, it has strategic alliance with REDHAT Inc. It is also NOVELL EDUCATION PARTNER with which it provides NOVELL and SUSE LINUX courses. Netmax technologies also conduct courses in CADENCE based design tools. Netmax Technologies also provide Technical Research & Development support and consultancy to some Electronics companies. Their clients for R&D support in field of embedded systems are: 1) 2) 3) 4) 5)

Recorders and Medicare ltd Chandigarh. TELEBOX India ltd. Lotus Machines Pvt. Ltd. Chandigarh. Impearl Electronics Pvt. Ltd. Chandigarh. KANTA Electrical Ltd. Mohali.

The partial list of our clients for network field is as below: 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) 14) 15) 16)

CEDTI, Mohali Premier ISP, Chandigarh Innovative Solutions, Chandigarh Emmtel ISP, Chandigarh NIPER, Mohali Navik Technologies, Chandigarh Software Technology Parks India, Mohali Glide Internet Services Rana Group IDS HFCL Infotel Ltd. Targus technologies pvt ltd STPI, Mohali BBMB The Tribune Quark 5

17)

Ind Swift

Support Area (Networking Solutions) a) LINUX / UNIX networks b) SUN networks c) CISCO devices (Routers, Switches, Firewalls, Cache Engine, RAS etc) d) Bandwidth Manager software and hardware e) Radio Links f) Security Solutions Design Services (Embedded Systems) a) AVR family b) MCS 51 c) ELECTRONIC SYSTEM DESIGN Network Training a) CISCO CCNA, CCNP b) RED HAT LINUX c) SUN SOLARIS d) WINDOWS 2000, 2003 Netmax Technologies is a leader in education services and developer of innovative embedded solutions. To meet the demands of Post PC era Netmax provides complete solutions as well as design-to-order services to satisfy its customers.

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PCB DESIGNING PCB stands for “PRINTED CIRCUIT BOARD”. Printed circuit board (PCB) provides both the physical structure for mounting and holding the components as well as the electrical interconnection between the components. That means a PCB = PWB (printed wiring board) is the platform upon which electronic components such as integrated circuit chips and other components are mounted. A PCB consists of a non-conducting substrate (typically fiber glass with epoxy as resin) upon which the conductive pattern or circuitry is formed. Copper is the most prevalent conductor although nickel, silver and tin are also used in some cases. Types of PCB PCB may be of different types:1) Single-sided 2) Double-sided 3) Multilayer Single sided PCBs: - As the name suggest in these designs the conductive pattern is only at in one side. And also the size is large in these case but these are cheap. Double sided PCBs: - These are the PCBs on which the conductive pattern is in on both sides. The size of board is small in this case but it is costlier than that of above. Multilayer PCBs: - In this case the board consists of alternating layers of conducting pattern and insulating material. The conductive material is connected across the layers through plated through holes. The size of this PCB is smaller than that of double sided PCB but it is very costly. PCBs may also be either rigid, flexible, or the combination of two (rigid-flex). When the electronic components have been mounted on the PCB, the combination of PCB and 7

components is an electronic assembly, also called PRINTED CIRCUIT ASSEMBLY. This assembly is the basic building block for all the electronic appliances such as television, computer and other goods. FUNCTIONS OF PCB Printed circuited boards are dielectric substrates with metallic circuitry formed on that. They are some times referred to as the base line in electronic packaging. Electronic packaging is fundamentally an inter connection technology and the PCB is the baseline building block of this technology. TECHNIQUES USED FOR PCB DESIGNING There mainly two techniques which are use for the PCB designs. 1. Hand Taping 2. Computer Aided Design 1) PCBs using Hand Taping: o PCB design using hand taping is the process of technical drawing. o In hand taping method layout should be prepared on grid paper. o In hand taping, components pads can be prepared by using black pads. o Routing of the board can be done by tapes with different widths. Each layer (top, bottom) has to prepare separately. DISADVANTAGS OF HAND-TAPING FOR PCB DESINING:

o Each layer has to be designed separately. o We cannot generate NCD files for CNC drilling. o Difficult to modify the design in the designing process or after designing. o Difficult to get good design overview.

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2) PCB DESIGNING USING CAD All the above difficulties can be removed by using CAB system. CAD system for PCB designing requires following: o A computer system. o PCB design software like OrCad, CADSTAR, Protel, TANGO, Mentor etc. o A photo plotter for art work generation. There are many enhanced features in electronics design automation tools which not possible in the hand taping. The main advantages are given below: o Auto placement o Auto routing o After routing, optimization of tracks can be done. o Provides physical design reuse modules o Electrical rule check (ERC) o All the layers are generated from the same design by giving different options. o Bill of material can be generated which contains number of different components used. o We can draw conductors as an arc, semi-circular at different angles. o Design Rule Check o Advanced CAD systems have high speed analysis. o CAD system provides all NCD files and Gerber data files for photo plotting. BASIC DESIGN STEPS IN CAD- SYSTEM The following design steps are very common while designing a PCD in CAD: 9

 Entry the schematic diagram.  Net list file creation.  Placement of components manually or automatically.  Routing of the board using manual routing tools or auto router  Design rule check physical and electrical.  Artwork generation. A TRADITIONAL DESIGN FLOW IN CAD- SYSTEM

Capture

Gerber tools

Libraries Layout Footprint libraries

Gerber and plotter drawing

Gerber and drill files

Overview of a PCB Design Software There many soft wares which are used for PCB designs. Some of them are given below: OrCad  CADSTAR  Protel  TANGO  Mentor 10

The most commonly software which are used for PCB design in India are Protel and OrCad

OrCad Design Environment OrCad has a long history of providing individuals and teams with a complete set of technologies that offer unprecedented productivity, seamless tool integration, and exceptional value. New 10.5 release continues that tradition. Today's lower cost and yet highly sophisticated electronic design automation systems have created a unique challenge to nearly every engineering department. Therefore the use of EDA tools has become increasingly important as product lifecycles have become shorter and shorter. Modern electronic design automation (EDA) tools are beginning to support a more efficient and integrated approach to electronic.OrCad Capture® design entry is the most widely used schematic entry system in electronic design today for one simple reason: fast and universal design entry. Whether you're designing a new analog circuit, revising schematic diagram for an existing PCB, or designing a digital block diagram with an HDL module, OrCad Capture provides simple schematic commands you need to enter, modify and verify the design for PCB. OrCad Layout ® offers PCB designers and PCB design teams the power and flexibility to create and share PCB data and constraints across the design flow. OrCad Layout delivers all the capabilities to designers need from netlist to place and route, to final output. The ease-of use and intuitive capabilities of OrCad Layout provides for quick startup and rapid learning right out of the box.

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PCB DESIGN STEPS IN OrCad 10.5 Entry of Schematic Diagram Schematic diagram provides the functional flow and the graphical representation of an electronic circuit. The entry of schematic diagram is the first step in PCB design using OrCad. A schematic diagram consists of: Electrical connections(nets)  Junctions  Integrated circuits symbols  Discrete components symbols like resistors, capacitors etc.  Input / output connectors  Power and ground symbols  Buses  No connection symbols  Components reference names  Text

The Schematic Page Editor: The schematic page editor is used to display and edit schematic pages. So that one can parts; wires; buses and draw graphics. The schematic page editor has a tool palette that you can use to draw and place everything you need to create a schematic page. One can print from within the schematic page editor, or from the project window.

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The Part editor: The part editor is used to create and edit parts. From the view menu of the part editor you can choose either part or package. In part view one can: Create and edit parts and symbols, then store in new or existing libraries.  Create and edit power and ground symbols, off-page connector symbols, and title block  Use the tool palette’s electrical tools to place pins on parts, and its drawing tools to draw parts and symbols. The Session Log: The session log lists the events that have occurred during the current Capture session, includes message resulting from using capture’s tools. To display context-sensitive

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help for an error message, put the cursor in the error message line in the session log press F1. The ruler along the top appears in either inches or mill meters, depending on which measurement system is selected in the window panel. Your tab setting are saved and used each time you start capture.

One can search for information in the session log using the find command on the Edit menu. You can also save the contents of the of the session log to a file, which is useful when working with Orcad’s technical support to solve technical problems. The default filename is SESSION.TXT. The Toolbar: Capture’s toolbar is dock able (that means you can select and drag the toolbar to new location) as well as resizable, and displays tool tips for each tool; by choosing a tool button

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you can quickly perform a task. If tool button is dimmed, you can’t perform that task in the current situation.

Some of the tools operate only on what you have selected, while others give you a choice of either operating on what is selected or expanding the scope to entire project. You can hide the toolbar, then display it again when u need it. For hiding select from the schematic page editor’s view menu, choose TOOLBAR.

The Tool Palette: Capture has two tool palettes: one for the schematic page editor and one for the part editor. Both tool palettes are dock able and resizable. They can also display tool tips that identify each tool. The drawing tools on the two tool palettes are identical, however, each tool palette has different electrical tools after you choose a tool, and you press the right mouse button to display a context- sensitive pop-up menu. The schematic page editor tool palette: The first group of tools on the tool palette is electrical tools, used to place electrical connectivity objects. The second group of tools is Drawing tools, used to create graphical objects without electrical connectivity.

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The part editor tool palette: The first group of tools on the part palette is electrical tools, used to place pins and symbols. They have been already explained above within the schematic page editor tools. The second group of tools is drawing tools, used to create graphical objects without objects any electrical connectivity and is described: Pin Tools: Place pins on part Pin Array: Place multiple pins on part Selecting and deselecting of objects Once one selects an object, one can perform operations on it, include moving, copying, cutting, mirroring, rotating, resizing, or editing. One can also select multiple, objects and edit them, or group them in to a single object. Grouping objects maintain relation ship among them while one moves them to another location.

Creating Net list File Net-list file is a document file which contains information about the logical interconnections between signals and pins. Before one create a net list file, be sure one’s project is completed, annotated and it is free from electrical rule violations. A net list file consists of nets, components, connectors, junctions, no connection symbol, power and ground symbols. 16

Creation of net list in capture:  Select your design in the project manager.  From the tools, choose create net list. The net list dialog box displays.  Choose a net list format tab.  If necessary, set the part value and PCB foot print combined property strings to reflect the information you want in the net list.  Click ok to create the net list.  In the net list file text box, enter a name for the output file. If the selected format creates an additional file, enter its file name in the second text box.

PLACEMENT OF LAYOUT PLUS What is Layout Plus? Layout plus is one part for the PCB design in which we place as well as route the components an set unit of measurement, grids, and spacing in OrCad. Within other soft wares you also have to place and route the components in similar way. For the placement and routing of the components we normally use auto-placement and auto-routing. Unfortunately, in a lot of soft wares some critical signals have to be routed manually before auto-routing. In layout plus we also define the layer stacks, pad stacks and via's. Steps for board design:  At first, we have created a net list from our schematic diagram by using capture.  Layout plus includes design rules in order to guide logical placement and routing. That means, load the net list into layout to create the board. At the same time you have to specify the board parameters.  Specify board parameters: Specifying global setting for the board, including nits of measurements, grid, and spacing 17

 Place components: Use the components tool in order to place manually the components which are fixed by the system designer on the board or otherwise use auto-placement.  Route the board: Use different routing technologies to route the board and take advantage of push and shove (a routing technology), which moves track you are currently routing as well as you can also auto route the board.  Provide finishing of the board: Layout supplies an ordered progression of commands on the auto menu for finishing your design. These commands include design rule check, cleanup design, rename components, back annotate, run post processor, and create reports. The design window: The design window provides a graphical display of printed circuit board, it is primary window you use when designing your board. It also provides tools to facilitate the design process such as to update components and design rule violation.

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Main window

Method to create a board with Layout Plus:  Ensure that net list with all footprints and necessary information has been created.  Create a directory in which the schematic design, net list, and boar will co-exit and put the schematic design and net list. OrCad provides a directory for this purpose.  From the layout session frame’s file menu, choose New. The load template file in the dialog box displayed.

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Design window  Select the technology template (.TCH), then choose the open button and load the net list in other box.  Then apply the auto ECO.  If necessary, respond to link footprints to component dialog.  Draw the board outline by using the obstacle tool in the tool bar. Setting board parameters: There is some parameter which should be set before placing the components on board. They are as follows:-

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 Set Datum  Create a board outline  Set units of measurements  Set system grid  Add mount holes Creating of board outline: Board outline is the graphical representation of the size of the actual PCB board. So it is the main step in layout, to draw the board outline of the actual size of PCB board. Placement of components: Placement of components means that to place the components in designed box. A designer should follow the following steps before going for it: Optimize the board for component placement.  Load the placement strategy file.  Place components on the board.  Optimize placement using various placements Components can be placed by using two techniques:1) Manual placement of components 2) Auto placement of components Choose the components tool bar button. From the pop up men, choose the queue for placement. The components selection criteria dialog box appears. Enter the reference designator of the components that you want to place in the appropriate text box, and click ok. Drag the components to desired location, place it there. 21

Conductor Routing in Layout:After placing all the components the other main step is to route the board from the electrical connections between the components. One may route board manually or automatically by auto router. 100% auto routing can be achieved only when components are placed in the order of functional flow of electronic circuit. The main routing tool available in OrCad is as flow: Add/edit route mode  Edit segment mode  Shove track mode 

Auto path route mode

Design Rule Check:In manual designs every thing was checked as a possible source of error. Components sizes, hole sizes, conductor widths and clearance, land-to-hole-ratio, board areas to be free of components, clearance to the edges, positional accuracy and of course electrical interconnections had tad to be personally reviewed with a great deal of care. After completing the design of printed circuit board with the help of an EDA-Tool, a designer has again to verify the PCB in order to find out errors. Such type of verifications/design rule check contains beside the general verifications commonly two types: Physical verification  Electrical verification

Post processing:Post processing can be done once the design is completed in all aspects. The common way is still a process to generate GERBER data and NCD files which can be used for photo plotting and for steps of CNC manufacturing and PCB- drilling. 22

POWER SYSTEM DESIGN First part of electronics ckts. is power. The main power supply is in AC but mostly electronic ckts. work with DC. So a system is required to convert ac to dc and these sources should able to produce stable supplies. Power supplies may be used in. may be of different types such as regulated, unregulated, smps etc. Unregulated power supplies These are the power supplies in which the out put is not constant. That it is varies with input voltage, load, and also effected by the environment conditions such as temperature, etc. so these are the variable supplies. Commonly these supplies are not employed as there efficiency is very less. The unregulated power can be obtained using rectifying circuit after AC supply. Regulated power supplies These are the power supplies in which the output voltage is constant, i.e. the out put voltage is independent of the input voltage, load and other external conditions. So to obtain the regulated voltage using different regulators. The regulator voltage is mainly the DC voltage, it may AC to or DC to DC voltage. A better approach to power supply design is to use enough capacitance to reduce ripple to low level, then use an active feedback circuit to eliminate the remaining ripple and dependence of output voltage on input, load and environment conditions. These active devices are known as Regulators. These regulators can be used to produce negative and positive voltage of required value. The voltage regulators are of three types:1) Constant positive voltage regulators 2) Constant negative voltage regulators 3) Variable voltage regulators Constant positive voltage regulators:-

These are the regulators which are able to

produce positive and constant voltage. Some of them are given below:23

S. no. Name of regulator Output voltage 1 LM 7805 5v 2 LM 7810 10v 3 LM 7812 12v 4 LM 7815 15v These regulators are used according to the required voltage need. Constant negative voltage regulators:- These are also the constant output voltage regulator but there output is negative in polarity. These regulators are also employed according to voltage requirements. Some of them are given below with there outputs:S. no 1 2 3 4

Name of regulator LM7905 LM7910 LM7912 LM7915

Output voltage -5v -10v -12v -15v

Variable voltage regulators:- These are the regulator whose output voltage can be varied according to the desired need. These regulators again of two types i.e.: Positive  Negative The output of these regulators can be varied by varying the resistance of the variable resistance which is connected to the adjustable pin the regulators. So these are the most commonly used regulators in the electronic industry as wide range of stable voltage can be obtained from single chip by varying the resistance connected to the adjustable pin of the regulators. The most commonly variable regulators are: LM317 (it is positive regulator)  LM 337(it is negative regulator) There description is given below:24

LM317 3-Terminal Adjustable Regulator:General Description: The LM317 series of adjustable 3-terminal positive voltage regulators is capable of supplying in excess of 1.5A over a 1.2V to 37V output range. They are exceptionally easy to use and require only two external resistors to set the output voltage. Further, both line and load regulation is better than standard fixed regulators. Also, the LM117 is packaged in standard transistor packages which are easily mounted and handled. In addition to higher performance than fixed regulators, theLM317 series offers full overload protection available only in IC’s. Included on the chip are current limit, thermal overload protection and safe area protection. All overload protection circuitry remains fully functional even if the adjustment terminal is disconnected. Normally, no capacitors are needed unless the device is situated more than 6 inches from the input filter capacitors in which case an input bypass is needed. An optional output capacitor can be added to improve transient response. The adjustment terminal can be bypassed to achieve very high ripple rejection ratios which are difficult to achieve with standard voltage, supplies of several hundred volts can be regulated as long as the maximum input to output differential is not exceeded, i.e., avoid short-circuiting the output. Also, it makes an especially simple adjustable switching regulator, a programmable output regulator, or by connecting a fixed resistor between the adjustment pin and output, theLM317 can be used as a precision current regulator. Supplies with electronic shutdown can be achieved by clamping the adjustment terminal to ground which programs the output to 1.2V where most loads draw little current. Typical application:

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U1 3

V IN

VOUT

2 VOUT

1

ADJ

VIN

L M 3 1 7 /C Y L

R1 220E

C1 .1 u F R2 5k

Features 1. Guaranteed 1% output voltage tolerance (LM317A) 2. Guaranteed max. 0.01%/V line regulation (LM317A) 3. Guaranteed max. 0.3% load regulation (LM317) 4. Guaranteed 1.5A output current 5. Adjustable output down to 1.2V 6. Current limit constant with temperature 7. P+ Product Enhancement tested 8. 80 dB ripple rejection 9. Output is short-circuit protected Packages of LM317

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C2 .1 u F

I

Application Hints: In operation, the LM317 develops a nominal 1.25V reference voltage, VREF, between the output and adjustment terminal. The reference voltage is impressed across program resistor R1 and, since the voltage is constant, constant current I1 then flows through the output set resistor R2, giving an output voltage of

Since the 100μA current from the adjustment terminal represents an error term, the LM317 was designed to minimize IADJ and make it very constant with line and load changes. To do this, all quiescent operating current 27

is returned to the output establishing a minimum load current requirement. If there is insufficient load on the output, the output will rise.

PROTECTION DIODES:When external capacitors are used with any IC regulator it is sometimes necessary to add protection diodes to prevent the capacitors from discharging through low current points into the regulator. Most 10μF capacitors have low enough internal series resistance to deliver 20A spikes when shorted. Although the surge is short, there is enough energy to damage parts of the IC. When an output capacitor is connected to a regulator and the input is shorted, the output capacitor will discharge into the output of the regulator. The discharge current depends on the value of the capacitor, the output voltage of the regulator, and the rate of decrease of VIN. In the LM317, this discharge path is through a large junction that is able to sustain 15A surge with no problem. This is not true of other types of

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positive regulators. For output capacitors of 25μF or less, there is no need to use diodes.

The bypass capacitor on the adjustment terminal can discharge through a low current junction. Discharge occurs when either the input or output is shorted. Internal to the LM317 is a 50r esistor which limits the peak discharge current. No protection is needed for output voltages of 25V or less and 10μF capacitance. Figure 3 shows an LM317 with protection diodes included for use with outputs greater than 25V and high values of output capacitance.

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LM337

3-Terminal Adjustable Regulator:-

General Description: The LM337 is adjustable 3-terminal negative voltage regulators capable of supplying in excess of −1.5A over an output voltage range of −1.2V to −37V. These regulators are exceptionally easy to apply, requiring only 2 external resistors to set the output voltage and 1 output capacitor for frequency compensation. The circuit design has been optimized for excellent regulation and low thermal transients. Further, the LM337 series features internal current limiting, thermal shutdown and safe-area compensation, making them virtually blowout-proof against overloads. The LM337 serves a wide variety of applications including local on-card regulation, programmable-output voltage regulation or precision current regulation. The LM337 are ideal complements to the LM317 adjustable positive regulators.

Pin diagram

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Features: 1) Output voltage adjustable from −1.2V to −37V 2) 1.5A output current guaranteed, −55°C to +150°C 3) Line regulation typically 0.01%/V 4) Load regulation typically 0.3% 5) Excellent thermal regulation, 0.002%/W 6) 77 dB ripple rejection 7) Excellent rejection of thermal transients 8) Temperature-independent current limit 9) Internal thermal overload protection 10) Standard 3-lead transistor package 11) Output is short circuit protected. These two Ic's i.e. LM337and LM317are mainly used in the regulated power supplies because using these regulator a wide range of output can be obtain which can be varied from 0v to 30v, which is much sufficient to drive any electronic circuit. 31

Bench supply diagram D2 1N 4007 2

1 L1

U5 L M 3 1 7 /TO 2 2 0 3

IN D U C T O R A U D IO _ 0 3 2 1

2

J7

AD J

2

V IN V O U T

VS

4 5 6

D3

CON3 1

R C 11

3

-

+

1

R 14 POT

C 13

4

R 13

R 15

C 15

R R 16

R

1K 1W

10uF 25V T A N T

C 16 CAP

1

2

U6 R 17 V IN

VOUT

L2

R

3

1

2

AD J

2200uF 50V

CAP

470uF 50V

R

CON3

C 14 C 17 104

1K 1W

R 12

R

470uF 50V

1 2 3

C 10

R 11

104 10uF 25V T A N T C 12

J8

R9

C9

2

BR1 B R ID G E

R 10 POT

1N 4007

C8

-V S

R8

1

2200uF 50V

1N 4007 D4

L M 3 3 7 /T O 2 2 0 1

2 D5 1N 4007

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1 2 3

6 5 4

-V S 1 2 3

IN D U C T O R A U D IO _ 0

EMBEDDED SYSTEM

What is Embedded System? Embedded system employs a combination of software & hardware to perform a specific function. It is a part of a larger system which may not be a “computer”Works in a reactive & time constrained environment. Any electronic system that uses a CPU chip, but that is not a general-purpose workstation, desktop or laptop computer is known as embedded system. Such systems generally use microprocessors; microcontroller or they may use custom-designed chips or both. They are used in automobiles, planes, trains, space vehicles, machine tools, cameras, consumer and office appliances, cell phones, PDAs and other handhelds as well as robots and toys. The uses are endless, and billions of microprocessors are shipped every year for a myriad of applications. In embedded systems, the software is permanently set into a read-only memory such as a ROM or flash memory chip, in contrast to a general-purpose computer that loads its programs into RAM each time. Sometimes, single board and rack mounted generalpurpose computers are called "embedded computers" if used to cont Embedded System Applications : Consumer electronics, e.g., cameras, cell phones etc.  Consumer products, e.g. washers, microwave ovens etc.  Automobiles (anti-lock braking, engine control etc.)  Industrial process controller & defense applications.  Computer/Communication products, e.g. printers, FAX machines etc.  Medical Equipments.  ATMs  Aircrafts

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DIFFERENCE BETWEEN MICROPROCESSORS AND MICROCONTROLLERS:  A Microprocessor is a general purpose digital computer central processing unit(C.P.U) popularly known as CPU on the chip. The Microprocessors contain no RAM, no ROM, and no I/P O/P ports on the chip itself.  On the other hand a Microcontroller has a C.P.U(microprocessor) in addition to a fixed amount of RAM, ROM, I/O ports and a timer all on a single chip.  In order to make a Microprocessor functional we must add RAM, ROM, I/O Ports and timers externally to them,i.e any amount of external memory can be added to it.  But in controllers there is a fixed amount of memory which makes them ideal for many applications.  The Microprocessors have many operational codes(opcodes) for moving data from external memory to the C.P.U  Whereas Microcontrollers may have one or two operational codes.

DISADVANTAGES OF MICROPROCESSORS OVER MICROCONTROLLERS  System designed using Microprocessors are bulky  They are expensive than Microcontrollers  We need to add some external devices such as PPI chip, Memory, Timer/counter chip, Interrupt controller chip,etc. to make it functional.

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Types of microcontroller architecture: There are two types of Microcontroller architecture designed for embedded system development. These are: 1)RISC- Reduced instruction set computer 2)CISC- Complex instruction set computer Difference between CISC and RISC: CISC stands for Complex Instruction Set Computer. Most PC's use CPU based on this architecture. For instance Intel and AMD CPU's are based on CISC architectures. Typically CISC chips have a large amount of different and complex instructions. In common CISC chips are relatively slow (compared to RISC chips) per instruction, but use little (less than RISC) instructions. MCS-51 family microcontrollers based on CISC architecture. RICS stands for Reduced Instruction Set Computer. The philosophy behind it is that almost no one uses complex assembly language instructions as used by CISC, and people mostly use compilers which never use complex instructions. Therefore fewer, simpler and faster instructions would be better, than the large, complex and slower CISC instructions. However, more instructions are needed to accomplish a task. Atmell’s AVR microcontroller based on RISC architecture. History of 8051 Intel Corporation introduced an 8-bit microcontroller called 8051 in 1981 this controller had 128 bytes of RAM, 4k bytes of on chip ROM, two timers, one serial port, and four ports all are on single chip. The 8051 is an 8 bit processor, meaning that the CPU can work on only 8 bit data at a time. Data larger than 8 bits broken into 8 bit pieces to be processed by CPU. It has for I/O 8 bit wide. Features of the 8051:Feature ROM RAM Timer I/O pins Serial port Interrupt sources

Quantity 4K bytes 128 bytes 2 32 1 6

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8051 Architecture Overview The 8051 family is one of the most common microcontroller architectures used worldwide. 8051 based microcontrollers are offered in hundreds of variants from many different silicon manufacturers .The 8051 is based on an 8-bit CISC core with Harvard architecture. It's an 8-bit CPU, optimized for control applications with extensive Boolean processing (single-bit logic capabilities), 64K program and data memory address space and various on-chip peripherals. The 8051 microcontroller family offers developers a wide variety of high-integration and cost-effective solutions for virtually every basic embedded control application. From traffic control equipment to input devices and computer networking products, 8051 u.c deliver high performance together with a choice of configurations and options matched to the special needs of each application. Whether it's low power operation, higher frequency performance, expanded on-chip RAM, or an application-specific requirement, there's a version of the 8051 microcontroller that's right for the job. When it's time to upgrade product features and functionality, the 8051 architecture puts you on the first step of a smooth and cost-effective upgrade path - to the enhanced performance of the 151 and 251 microcontrollers.

36

Block diagram of 8051

37

Internal Architecture of 8051

38

Pin configuration of 8051

39

There are four ports P0, P1, P2 and P3 each use 8 pins, making them 8-bit ports. All the ports upon RESET are configured as output, ready to be used as output ports. To use any of these ports as an input port, it must be programmed. Port 0:- Port 0 occupies a total of 8 pins (pins 32-39) .It can be used for input or output. To use the pins of port 0 as both input and output ports, each pin must be connected externally to a 10K ohm pull-up resistor. This is due to the fact that P0 is an open drain, unlike P1, P2, and P3.Open drain is a term used for MOS chips in the same way that open collector is used for TTL chips. With external pull-up resistors connected upon reset, port 0 is configured as an output port. For example, the following code will continuously send out to port 0 the alternating values 55H and AAH Port 0 as input:- With resistors connected to port 0, in order to make it an input, the port must be programmed by writing 1 to all the bits. In the following code, port 0 is configured first as an input port by writing 1's to it, and then data is received from the port and sent to

40

P1.

Dual Role of Port 0 :-Port 0 is also designated as AD0-AD7, allowing it to be used for both address and data. When connecting an 8051/31 to an external memory, port 0 provides both address and data. The 8051 multiplexes address and data through port 0 to save pins. ALE indicates if P0 has address or data. When ALE = 0, it provides data D0-D7, but when ALE =1 it has address and data with the help of a 74LS373 latch. Port 1:- Port 1 occupies a total of 8 pins (pins 1 through 8). It can be used as input or output. In contrast to port 0, this port does not need any pull-up resistors since it already has pull-up resistors internally. Upon reset, Port 1 is configured as an output port. For 41

example, the following code will continuously send out to port1 the alternating values 55h & AAh Port 1 as input:-To make port1 an input port, it must be programmed as such by writing 1 to all its bits. In the following code port1 is configured first as an input port by writing 1’s to it, then data is received from the port and saved in R7 ,R6 & R5. Port 2 :-Port 2 occupies a total of 8 pins (pins 21- 28). It can be used as input or output. Just like P1, P2 does not need any pull-up resistors since it already has pull-up resistors internally. Upon reset,Port 2 is configured as an output port. For example, the following code will send out continuously to port 2 the alternating values 55h and AAH. That is all the bits of port 2 toggle continuously. Port 2 as input:- To make port 2 an input, it must programmed as such by writing 1 to all its bits. In the following code, port 2 is configured first as an input port by writing 1’s to it. Then data is received from that port and is sent to P1 continuously.

Dual role of port 2:- In systems based on the 8751, 8951, and DS5000, P2 is used as simple I/O. However, in 8031-based systems, port 2 must be used along with P0 to provide the 16-bit address for the external memory. As shown in pin configuration 8051, port 2 is also designed as A8-A15, indicating the dual function. Since an 8031 is capable of accessing 64K bytes of external memory, it needs a path for the 16 bits of the address. While P0 provides the lower 8 bits via A0-A7, it is the job of P2 to provide bits A8-A15 of the address. In other words, when 8031 is connected to external memory, P2 is used for the upper 8 bits of the 16 bit address, and it cannot be used for I/O.

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Port 3:- port 3 occupies a total of 8 pins, pins 10 through 17. It can be used as input or output. P3 does not need any pull-up resistors, the same as P1 and P2 did not. Although port 3 is configured as an output port upon reset. Port 3 has the additional function of providing some extremely important signals such as interrupts. This information applies both 8051 and 8031 chips. There functions are as follows:PORT 3 P3.0 P3.1 P3.2 P3.3 P3.4 P3.5 P3.6 P3.7

Function RxD TxD ___ Int0 ___ Int1 T0 T1 ___ WR ___ RD

pin 10 11 12 13 14 15 16 17

P3.0 and P3.1 are used for the RxD and TxD serial communications signals. Bits P3.2 and P3.3 are set aside for external interrupts. Bits P3.4 and

P3.5 are used for timers 0 and 1. Finally P3.6 and P3.7 are used to provide the WR and RD signals of external memories connected in 8031 based systems.

ALE/PROG Address Latch Enable is an output pulse for latching the low byte of the address during accesses to external memory. This pin is also the program pulse input (PROG) during Flash programming. In normal operation, ALE is emitted at a constant rate of 1/ 6 the oscillator frequency and may be used for external timing or clocking purposes. Note, however, that one ALE pulse is skipped during each access to external data memory. If desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the bit set, ALE is active only during a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled high. Setting the ALE-disable bit has no effect if the microcontroller is in external execution mode. PSEN Program Store Enable is the read strobe to external program memory. When the AT89S8252 is executing code from external program memory, PSEN is activated twice each machine 43

cycle, except that two PSEN activations are skipped during each access to external data memory. EA/VPP External Access Enable. EA must be strapped to GND in order to enable the device to fetch code from external program memory locations starting at 0000H up to FFFFH. Note, however, that if lock bit 1 is programmed, EA will be internally latched on reset. EA should be strapped to VCC for internal program executions. This pin also receives the 12volt programming enable voltage (VPP) during Flash programming when 12-volt programming is selected. XTAL1 Input to the inverting oscillator amplifier and input to the internal clock operating circuit. XTAL2 Output from the inverting oscillator amplifier.

AT89s8252 AT89S8252 is an ATMEL controller with the core of intel MCS-51. It has same pin configuration as give above. The AT89S8252 is a low-power, high-performance CMOS 8-bit microcomputer with 8K bytes of Downloadable Flash programmable and erasable read only memory and 2K bytes of EEPROM. The device is manufactured using Atmel’s high density nonvolatile memory technology and is compatible with the industry standard 80C51 instruction set and pinout. The on-chip Downloadable Flash allows the program memory to be reprogrammed insystem through an SPI serial interface or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Downloadable Flash on a monolithic chip, the Atmel AT89S8252 is a powerful microcomputer which provides a highly flexible and cost effective solution to many embedded control applications. The AT89S8252 provides the following standard features: 8K bytes of Downloadable Flash, 2K bytes of EEPROM, 256 bytes of RAM, 32 I/O lines, programmable watchdog timer, two Data Pointers, three 16-bit timer/counters, a six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator, and clock circuitry. In addition, the AT89S8252 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port, and interrupt system to continue functioning. The Power Down Mode saves the RAM contents but freezes the oscillator, disabling all other chip functions until the next interrupt or hardware reset. The Downloadable Flash can be changed a single byte at a time and is accessible through the SPI serial interface. Holding RESET active forces the SPI bus into a serial programming interface and allows the program memory to be written to or read from unless Lock Bit 2 has been activated. 44

Features • Compatible with MCS-51™Products • 8K bytes of In-System Reprogrammable Downloadable Flash Memory - SPI Serial Interface for Program Downloading - Endurance: 1,000 Write/Erase Cycles • 2K bytes EEPROM - Endurance: 100,000 Write/Erase Cycles • 4.0V to 6V Operating Range • Fully Static Operation: 0 Hz to 24 MHz • Three-Level Program Memory Lock • 256 x 8 bit Internal RAM • 32 Programmable I/O Lines • Three 16 bit Timer/Counters • Nine Interrupt Sources • Programmable UART Serial Channel • SPI Serial Interface • Low Power Idle and Power Down Modes • Interrupt Recovery From Power Down • Programmable Watchdog Timer • Dual Data Pointer • Power Off Flag

Pin Description Furthermore, P1.4, P1.5, P1.6, and P1.7 can be configured as the SPI slave port select, data input/output and shift clock input/output pins as shown in the following table.

45

Port 1 also receives the low-order address bytes during Flash programming and verification.

Hardware interfacings and programming There are two types of programming language used for microcontroller programming: 1)Low Level Language(Assembly Language) 2) High Level Language(C Language)_ ALE/PROG Address Latch Enable is an output pulse for latching the low byte of the address during accesses to external memory. This pin is also the program pulse input (PROG) during Flash programming. In normal operation, ALE is emitted at a constant rate of 1/ 6 the oscillator frequency and may be used for external timing or clocking purposes. Note, however, that one ALE pulse is skipped during each access to external data memory. If desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the bit set, ALE is active only during a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled high. Setting the ALE-disable bit has no effect if the microcontroller is in external execution mode. PSEN Program Store Enable is the read strobe to external program memory. When the AT89S8252 is executing code from external program memory, PSEN is activated twice each machine 46

cycle, except that two PSEN activations are skipped during each access to external data memory. EA/VPP External Access Enable. EA must be strapped to GND in order to enable the device to fetch code from external program memory locations starting at 0000H up to FFFFH. Note, however, that if lock bit 1 is programmed, EA will be internally latched on reset. EA should be strapped to VCC for internal program executions. This pin also receives the 12volt programming enable voltage (VPP) during Flash programming when 12-volt programming is selected. XTAL1 Input to the inverting oscillator amplifier and input to the internal clock operating circuit. XTAL2 Output from the inverting oscillator amplifier. Hardware interfacings and programming There are two types of programming language used for microcontroller programming: 1)Low Level Language(Assembly Language) 2) High Level Language(C Language)

Programming in assembly language: TOOLS USED: 1). 8051 assembler cum simulator. 2).command prompt as a programming environment. Introduction to programming in assembly language: assembly languages were developed that provided mnemonics for the machine code instructions, plus others features that made programming faster and less prone to error.The term mnemonic is frequently used in computer science and engg. literature to refer to codes and abbreviations that are relatively easy to remember .Asssembly language programs must be translated into 47

machine code by a program called an ASSEMBLER.Assembly language is referred to as a low-level-language . Now we look at 8051 assembly language format and use an 8051 Assembler to create a ready-to run program. An assembly language instruction consists of four field’s:[label:]

mnemonic

[operands]

[;comment]

Brackets indicates that a field is optional,and not all lines have them.Bracket should not be typed in. 1.The label field allows the program to refer to a line of code by name.the label field can not exceed a certain no. of character’s. 2.The assembly language mnemonics(instruction) and operands fields together perform the real work of the program and accomplish the tasks for which the program was written. 3.The comment field begins with a “;”. Comments may be at the and of a line or on a line by themselves’s . 8051 basic instructions: we describe the basic instructions of the 8051 and give their formats with some examples. 1).arithmetic instructions 2).logical instructions 3).jump,loop,call instructions arithmetic instructions: the arithmetic instructions are used to perform arithmetic operations like addition,subtraction ,multiplication, division etc. 1)ADD:- this instruction is used to add 2 operands.the 1 operand should be in accumulator and 2 in the other register. eg.

MOV R0,#20 MOV A,#10 ADD A,R0 MOV P1,A Here,# is used to load immediate value and we observe the final value on port 1.

2)MUL:-this instruction is used to multiply 2 operands. the 1 operand should be in accumulator and 2 in the other register. 48

eg. MOV R0,#20 MOV A,#10 MUL AB MOV P1,A Here,# is used to load immediate value and we observe the final value on port 1.

3)DIV:- this instruction is used to divide 2 operands. the 1 operand should be in accumulator and 2 in the other register. eg. MOV R0,#20 MOV A,#10 DIV AB MOV P1,A Here,# is used to load immediate value and we observe the final value on port 1. logical instructions: Apart from the input/output instructions ,logic instructions are some of the most widely used instructions.the logical instructions are used to perform logical operations likeAND,OR,EXOR etc. 1).

MOV A,#35H ANL A,#0FH

;A=35H ;A AND 0FH(now A=05)

According to this operation, the content 35H gets ANDing with 0FH. 2).

MOV A,#04 ORL A,#30H

;A=04 ;A=A OR 30H(now A=34H)

According to this operation, the content 35H gets ANDing with 0FH. Jump,loop,call instructions: the Jump,loop,call instructions are used to perform logical operations in the sequence of instructions to be executed ,it is often necessary to transfer program control to a different location.

49

We have used high level language for microcontroller programming due to its given advantages over assembly: Advantages of C over Assembly language programming:



Knowledge of the processor instruction set is not required.



Details like register allocation and addressing of memory and data is managed by the compiler.



Programs get a formal structure and can be divided into separate functions.



Programming and program test time is drastically reduced, this increases efficiency.



Keywords and operational functions can be used that come closer to how humans think.



The supplied and supported C libraries contain many standard routines such as numeric conversions.



Reusable code: Existing program parts can be more easily included into new programs, because of the comfortable modular program construction techniques.



The C language based on the ANSI standard is very portable. Existing programs can be quickly adapted to other processors as needed.

THE 8051 INTERRUPTS There are two methods in which a micro-controller can provide its services to its internal and external environment: 1) POLLING: Microcontroller checks the device continuously while using this method. But it results in wastage of machine cycles of the micro-controller. 2) INTERRUPTS: Here every device tells the micro-controller when it needs the services from microcontroller. 50

Actually, only 5 interrupts are available to the user in the 8051, but many manufacturers data sheets state that there are 6 interrupts since they include reset. The 6 interrupts in the 8051 are allocated as follows: 1).Reset: when the reset pin is activated, the 8051 jumps to address location 0000.this is the power-up reset. 2).Two interrupts are set aside for the timers: One for timer 0 and one for timer 1.memory locations 000BH and 001BH in the interrupt vector table belong to timer0 and timer1, respectively. 3).Two interrupts are set aside for hardware external hardware interrupts. Pin numbers 12(p3.2) and 13(p3.3) in port 3 are the external hardware interrupts INT0 and INT1, respectively. These external interrupts are also referred to as EX1 and EX2. 4).Serial communication has a single interrupts that belongs to both receive and transmit.

ELECTROMAGNETIC RELAYS A relay is an electrically controllable switch widely used in industrial controls, automobiles and appliances. It allows the isolation of two separate sections of a system with two different voltage sources. The electromechanical (or electromagnetic) relay (EMR) has 3 components: the coil, spring and contacts. When current flows through the coil, a magnetic field is created around the coil (the coil is energized) which causes the armature to be attracted to the coil. The armature’s contact acts like a switch and closes or opens a circuit. When the coil is not energized, a spring pulls the armature to its normal state of open or closed. In choosing a relay, the following characteristics need to be considered: 1) 2) 3)

The contacts can be normally open (NO) or normally closed (NC). In the NC type, the contacts are closed when the coil is not energized. In the NO, the contacts are open when the coil is un-energized. There can be one or more contacts (SPST, SPDT, DPDT relays). The voltage and current needed to energize the coil. The voltage can vary from a few volts to 50 volts, while the current can be from few mA to 20mA. The relay has a minimum voltage below which the coil will not be energized. This minimum voltage is called the “pull-in” voltage.

51

INTERFACING OF VARIOUS DEVICES 1) LED Interfacing VCC BC 547A

Q 14

R 62

VCC

31

Y8 E A /V P P

33pF C 45

U 10

1 2

4 3 33pF C 46

19 18 9 12 13 14 15

VC C

XTA L1 XTA L2 R ST

VCC

8 M hz

P 0 .0 /A D P 0 .1 /A D P 0 .2 /A D P 0 .3 /A D P 0 .4 /A D P 0 .5 /A D P 0 .6 /A D P 0 .7 /A D

330E

LE D

Q 15

C 48 104

R 61 BC 547A

40

VC CVC C

D 29

0 1 2 3 4 5 6 7

P 3 .2 /IN T 0 P 3 .3 /IN T 1 P 2 .0 /A 8 P 3 .4 /T 0 P 2 .1 /A 9 P 3 .5 /T 1 P 2 .2 /A 1 0 P 2 .3 /A 1 1 P 2 .4 /A 1 2 P 2 .5 /A 1 3 P 2 .6 /A 1 4 P 2 .7 /A 1 5

39 38 37 36 35 34 33 32

D 28

330E

LE D

R 41 BC 547A

D 27

330E

LE D

VCC Q 16

21 22 23 24 25 26 27 28

VCC Q 17 R 40 BC 547A

D 26

VCC C 47 1 0 u F /1 6 V

P 3 .7 /R D P 1 .0 /T 2 P 3 .6 /W R P 1 .1 /T 2 -E X PSEN P 1 .2 A L E /P R O G P 1 .3 P 3 .1 /TXD P 1 .4 /S S P 3 .0 /R X D P 1 .5 /M O S I P 1 .6 /M IS O P 1 .7 /S C K

17 16 29 30 11 10

GND

R7 10K

1 2 3 4 5 6 7 8

330E

Q 18 BC 547A

LE D

D 25

R 63 VCC

330E

LE D

Q 19 BC 547A

D 24

20

AT89S8252

R 39 VCC

330E

LE D

Q 20 BC 547A

D 23

R 38 330E

LE D

VCC Q 21 BC 547A R 37

Hardware interfacing of LED with AT89s8252

330E

D 22

LE D

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S iz e D ocum ent N um ber C u s to m< D o c > D a te :

52

Tuesday , D ecem ber 26, 2006

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C code for Blinking LEDs connected on PORT2: #include void delay(unsigned int i); void main(void) { While(1) { P2=0x00; Delay(0xffff); P2=0x00; Delay(0xff); } } void delay(unsigned int i) { while(i!=0) { i--; } } C code for running LED connected on PORT2: #include void delay(unsigned int i); void main () { P0=0x00; while (1) { delay(0xffff); P2_0=1; delay(0xffff); P2_0=0; P2_1=1; delay(0xffff); P2_1=0; P2_2=1; 53

delay(0xffff); P2_2=0; P2_3=1; delay(0xffff); P2_3=0; P2_4=1; delay(0xffff); P2_4=0; P2_5=1; delay(0xffff); P2_5=0; P2_6=1; delay(0xffff); P2_6=0; P2_7=1; delay(0xffff); P2_7=0; P2_0=1 } } void delay(unsigned int i) { while (i!=0) { i--; } } 2) Hardware interfacing of LCD(JHD162A): On most displays, the pins are numbered on the LCD’s printed circuit board, but if not, it is quit easy to locate pin1. Since the pin is connected to ground, it often has a thicker PCB track connected to it, and it is generally connected to the metal work at some point.

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The function of each of the connections is shown in the table below:Pins 1 & 2 are the power supply lines, Vss & Vdd. The Vdd pin should be connected to the positive supply & Vss to the 0V supply or ground. Although the LCD module data sheets specify 5V D.C. supply (at only a few milliamps), supplies of 6V & 4.5V both work well, and even 3V is sufficient for some modules. Consequently, these modules can be effectively and economically powered by batteries. Pin 3 is a control pin, Vee, which is used to alter the contrast of the display. Ideally, these pin should be connected to a variable voltage supply. A preset potentiometer connected between the power supply lines, with its wiper connected to the contrast pin is suitable in many cases, but be aware that some modules may require a negative potential; as low as 7V in some cases. For absolute simplicity, connecting this pin to 0V will often suffice. Pin 4 is register select (RS) line.

PIN NO. 1 2 3

NAME Vss Vdd Vee

FUNCTION Ground +ve supply contrast 55

4 5 6 7 8 9 10 11 12 13 14

RS R/W E D0 D1 D2 D3 D4 D5 D6 D7

Register select Read/Write Enable Data Bit 0 Data Bit 1 Data Bit 2 Data Bit 3 Data Bit 4 Data Bit 5 Data Bit 6 Data Bit 7

Three command control inputs. When this line is low, data bytes transferred to the display are treated as commands, and data bytes read from the display indicate its status. By setting the RS line high, character data can be transferred to and from the module. Pin 5 is (R/W) line. This line is pulled low in order to write commands or character data to the module, or pulled high to read character data or status information from its registers. Pin 6 is Enable (E) line. This input is used to initiate the actual transfer of commands or character data between the module and the data lines. When writing to the display, data is transferred only on the high to low transition of this signal. However, when reading from the display, data will become available shortly after the low to high transition and remain available until the signal falls low again. Pins 7 to 14 are the eight data bus lines (D0 to D7). Data can be transferred to and from the display, either as a single 8-bit byte or as two 4-bit “nibbles”. In the latter case, only the upper four data lines (D4 to D7) are used. This $-bit mode is beneficial when using a microcontroller, as fewer I/O lines are required.

56

LC D

12

4 3 33pF

C 2

19 18 9 12 15

VC C

E A /V P P

Y 1

XTA L1 XTA L2 R ST

P 1 .0 /T2 P 1 .1 /T 2 -E X P 1 .2 P 1 .3 P 1 .4 /S S P 1 .5 /M O S I P 1 .6 /M IS O P 1 .7 /S C K

P 3 .2 /IN T 0 P 3 .3 /IN T 1 P 3 .4 /T0

P 2 .0 /A 8 P 2 .1 /A 9 P 2 .2 /A 1 0 P 2 .3 /A 1 1 P 2 .4 /A 1 2 P 2 .5 /A 1 3 P 2 .6 /A 1 4 P 2 .7 /A 1 5

P P P P P P P P

0 .7 /A 0 .6 /A 0 .5 /A 0 .4 /A 0 .3 /A 0 .2 /A 0 .1 /A 0 .0 /A

AT89S52

D D D D D D D D

7 6 5 4 P 3 .7 /R D 3 P 3 .6 /W R 2 PSEN 1 A L E /P R O G 0 P 3 .0 /R XD P 3 .1 /T XD G N D

32 33 34 35 36 37 38 39

13 14

RS EN

21 22 23 24 25 26 27 28 17 16 29 30 10 11

20

R 1 10K

1 2 3 4 5 6 7 8

P 3 .5 /T1

VC C C 3 10uF 16V

56E

40

U 1

31

VC C

33pF C 1

R 52

VC C

VC C

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

J2

Hardware intetrfacing of LCD with AT89s52 microcontroler

C code for LCD display #include #define LCDPRT P1 #define RS P3_3 #define EN P3_4 void delay(unsigned int i); void lcd_cmd(unsigned char a); void display(unsigned char b); void wait(void); void Init_lcd(void); void cursor_position(unsigned char c); void main(void) { init_lcd(); 57

while(1) { cursor_position(0x01); display('N'); cursor_position(0x02); display('E'); cursor_position(0x03); display('T'); cursor_position(0x04); display('M'); cursor_position(0x05); display('A'); cursor_position(0x06); display('X'); } } void delay (unsigned int i) { while (i!=0) { i--; } } void lcd_cmd(unsigned char a) { wait(); LCDPRT=a; RS=0; EN=1; EN=0; } void display(unsigned char b) { wait (); LCDPRT=b; RS=1; EN=1; 58

EN=0; } void wait(void) { unsigned int count=300; while(count!=0) { count--; } } void Init_lcd(void) { lcd_cmd(0x3c); lcd_cmd(0x0c); lcd_cmd(0x06); lcd_cmd(0x01); } void clear_lcd(void) { lcd_cmd(0x01); } void cursor_position(unsigned char c) { lcd_cmd(c+0x80); } C code for string display on LCD: #include #define LCDPRT P1 #define RS P3_3 #define EN P3_4 code unsigned char name_arry[]={"NETMAX$"}; void display_string(unsigned char *sp); void lcd_cmd(unsigned char a); void display(unsigned char b); void wait(void); void Init_lcd(void); 59

void cursor_position(unsigned char c); void main(void) { Init_lcd(); cursor_position(0x40); display_string(&name_arry); } void display_string(unsigned char *sp) { while(*sp!='$') { display(*sp); sp=sp+1; } }

void lcd_cmd(unsigned char a) { wait (); LCDPRT=a; RS=0; EN=1; EN=0; } void display(unsigned char b) { wait (); LCDPRT=b; RS=1; EN=1; EN=0; } void wait(void) { unsigned int count=300; 60

while(count!=0) { count--; } } void Init_lcd(void) { lcd_cmd(0x3c); lcd_cmd(0x0c); lcd_cmd(0x06); lcd_cmd(0x01); } void cursor_position(unsigned char c) { lcd_cmd(c+0x80); }

3) ADC-0804 interfacing with AT89s52: The ADC0804 family is CMOS 8-Bit, successive-approximation A/D converters which use a modified potentiometer ladder and are designed to operate with the 8080A control bus via three-state outputs. These converters appear to the processor as memory locations or I/O ports, and hence no interfacing logic is required. The differential analog voltage input has good common mode- rejection and permits offsetting the analog zero-input voltage value. In addition, the voltage reference input can be adjusted to allow encoding any smaller analog voltage span to the full 8 bits of resolution.

Features • 80C48 and 80C80/85 Bus Compatible - No Interfacing Logic Required • Conversion Time < 100s • Easy Interface to Most Microprocessors • Differential Analog Voltage Inputs 61

• TTL Compatible Inputs and Outputs • On-Chip Clock Generator • 0V to 5V Analog Voltage Input Range (Single + 5V Supply) • No Zero-Adjust Required

PIN DIAGRAM

62

Hardware interfacing of ADC-0804 for Temperature monitoring C O N 16_0

1 3 2 1 1 1

1 0 9 6 0 7

D D D D D D D D

VC C VC C R 6 220E

VC C

P P P P P P P P

0 .7 0 .6 0 .5 0 .4 0 .3 0 .2 0 .1 0 .0

P A P P P P

3 .1 /T XD L E /P R O G 15 SEN P 3 .5 /T 1 3 .6 /W R P 3 .2 /IN T 0 1 2 3 .0 /R XD 3 .7 /R D

A T89S 8252

1

R 53 1k

7 6 5 4 3 2 1 0

U 4 AD C 0804

P P P2 P2 P2 P2 P2 P2

2 .0 /A 2 .1 /A .2 /A 1 .3 /A 1 .4 /A 1 .5 /A 1 .6 /A 1 .7 /A 1

8 9 0 1 2 3 4 5

2 2 2 2 2 2 2 2

1 2 3 4 5 6 7 8

1 1 1 1 1 1 1 1

EOC

8 7 6 5 4 3 2 1 5

SOC

D D D D D D D D

B B B B B B B B

0 1 2 3 4 5 6 7

+ IN -IN V R E F /2 C LK R C L K IN

IN T R

C S R D W R

C 9 C AP

6 7

3

P 3 .3 /IN T 1 P 3 .4 /T 0 /A /A /A /A /A /A /A /A

VC C

1 R 5 10K

2

R ST

G N D O U TPU T

G N D

R 2 10K

2 3 4 5 6 7 8 9

XTA L1 XTA L2

3

1 2 3 4 5 6 7 8

20

3 3 3 3 3 3 C 6 3 10uF 16V 3

U 2 2 L M 3 5 /S O

U 21 TL431

9 19 4 1 2 3

10

VC C

13 14

R 55 56E

V C C /V R E F

R S EN

9

EN

AG N D

C 5

R S

8

33pF

19 18

G N D

3

P 1 .0 /T 2 P 1 .1 /T 2 -E X P 1 .2 P 1 .3 P 1 .4 /S S P 1 .5 /M O S I P 1 .6 /M IS O P 1 .7 /S C K

20

12

4

VC C

E A /V P P

33pF C 4 Y 2

VC C

2

U 2

31

C R Y S TA L

C 13 104

40

VC C VC C

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

LC D

C 8 1 u f /1 6 v

R 17 10K C 7 150pF

Temprature monitoring

When interfacing is being done then

system

gets lowered then only it allows the

controller to read the data, otherwise controller can not read the data. is always grounded. is software controlled.

C- code For temperature monitoring system #include #define LCDPRT P1 #define RS P3_3 #define EN P3_4 #define SOC P3_2 63

C 14 1 u f /16 v

#define EOC P3_5 unsigned char read_adc(void); void delay(unsigned int i); void lcd_cmd(unsigned char a); void display(unsigned char b); void wait(void); void Init_lcd(void); void clear_lcd(void); void cursor_position(unsigned char c); void disp_dec(unsigned int digit); code unsigned char table[16]={'0','1','2','3','4','5','6','7','8','9'}; void main(void) { unsigned char e; P2=0xff; Init_lcd(); while(1) { cursor_position(0x00); e=read_adc(); disp_dec(e); } } unsigned char read_adc(void) { unsigned char n; SOC=0; SOC=1; while(EOC==1) { n=P2; } return n; } void delay (unsigned int i) { while (i!=0) { i--; } } 64

void lcd_cmd(unsigned char a) { wait(); LCDPRT=a; RS=0; EN=1; EN=0; } void display(unsigned char b) { wait (); LCDPRT=b; RS=1; EN=1; EN=0; } void wait(void) { unsigned int count=300; while(count!=0) { count--; } } void Init_lcd(void) { lcd_cmd(0x3c); lcd_cmd(0x0c); lcd_cmd(0x06); lcd_cmd(0x01); }

void cursor_position(unsigned char c) { lcd_cmd(c+0x80); } void disp_dec(unsigned int digit) { 65

unsigned int temp; if(digit99 && digit>4; y=y|0x30; display(y); display(x); }

73

6) 8051 Interrupt Programming C-code for handling of INT0 interrupt: #include void delay(unsigned int i) { while(i!=0) i--; } void int0(void) interrupt 0 { if(INT0==0) { while(1) { P0=0xF0; delay(0xFFFF); P0=0x0F; delay(0xFFFF); }}} void main() { EA=1; EX0=1; While(1) { P0=0xFF; delay(0xFFFF); P0=0x00; delay(0xFFFF); }}

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75