avr training report

8/13/2019 Avr Training Report

1/56

1

SOFCON INDIA PVT. LTD.

TRAINING REPORT

On

AVR MICROCONTROLLER

Submitted to Kurukshetra University in partial fulfillment of therequirement for the award of the degree of

BACHELOR OF TECHNOLOGY

ELECTRONICS & COMMUNICATION ENGINEERING

Submitted ByPRASHANT SETHIRoll No. 4110253

DEPTT. OF ELECTRONICS & COMMUNICATION ENGINEERING

YAMUNA INSTITUTE OF ENGINEERING & TECHNOLOGY

GADHOLI, YAMUNANAGAR-1350032013-14


2/56

2

PREFACE

Training is an integral part of B.Tech and each and every student has to undergo the

training for 6 weeks in a company.

This record is concerned about our practical training during the Summer Vacations of 3rd

year. I have taken my Practical training in AVR MICROCONTROLLER.

During this training, we got to learn many new things about the industry and the current

requirements of companies. This training proved to be a milestone in our knowledge of

present industry scenario and developing business of software in the giant economic field

of computers. Every say and every moment was an experience in itself, an experience

which theoretical study cant provide.


3/56

3

ACKNOWLEDGEMENT

It is my pleasure to be indebted to various people, who directly or indirectly contributed

in the development of this work and who influenced my thinking, behaviour and actsduring the course of study.

I express my sincere gratitude to Dr. Rajiv Khandujaworthy Principal for providing me

an opportunity to undergo summer training at SOFCON INDIA PVT. LTD

I am thankful to Er. Manpreet Singh, H.O.D., ECE Depttfor his support, cooperation,

and motivation provided to me during for constant inspiration, presence and blessings.

I also extend my sincere appreciation to Er. Lalitesh Sehgal , Coordinator who

provided his valuable suggestions and precious time in accomplishing my training report.

Prashant Sethi

(4110253)


4/56

4

DECLARATION

I, Prashant Sethi, Roll No. 4110253, B.Tech (Semester- VII) of the YamunaInstitute of

Engg. & Technology, Gadholi (Yamuna Nagar) hereby declare that the Training

Report entitled AVR MICROCONTROLLERS is an original work and data

provided in the study is authentic to the best of my knowledge.This report has not been

submitted to any other Institute for the award of any other degree.

Place: Prashant Sethi

Date: (4110253)

This is to certify that above statement made by the candidate is correct to the best of

my knowledge.

Approved by:

Er. Lalitesh Sehgal Er. Manpreet Singh

( Coordinator) ( H.O.D., ECE Deptt.)


5/56

5

Contents

CHAPTER 2 :ATMEL AVR: ........................................................................................... 16

2.1 Introduction ................................................................................................................. 18

2.2 Brief history ................................................................................................................ 18

2.3 Device overview ......................................................................................................... 19

2.4 Basic families .............................................................................................................. 19

2.5 Device architecture ..................................................................................................... 20

2.9 Program execution ...................................................................................................... 22

2.10 Instruction set ............................................................................................................ 22

2.11 MCU speed ............................................................................................................... 23

2.12 Development ............................................................................................................. 24

2.13 Features ..................................................................................................................... 24

CHAPTER 3

3.6 Interfacing LCD with AVR ........................................................................................ 37

Types of stepper motor ..................................................................................................... 46

Driving Stepper Motor with AVR MCU .......................................................................... 46

ADC Interfacing of AVR (ATmega32) ............................................................................ 47


6/56

6

LIST OF FIGURES

Figure Title Page No

1.1.1 Basic diagram of embedded system..................................................8

1.1.2 Influence of embedded system on ubiquitous computing................11

3.1.1 Seven Segment Display....................................................35

3.1.2 LCD......................................................................................38

3.1.3 Pin Description of lcd....................................................................39


7/56

7

Chapter 1

INTRODUCTION TO EMBEDDED SYSTEM


8/56

8

1.1 Embedded system

Figure1.1.1 Basic diagram of embedded system

Until the late eighties, information processing was associated with large mainframe

computers and huge tape drives. During the nineties, this shifted towards information

processing being associated with personal computers, PCs. The trend towards

miniaturization continues and the majority of information processing devices will be

small portable computers integrated into larger products. Their presence in these larger

products, such as telecommunication equipment will be less obvious than for the PC.

Hence, the new trend has also been called the disappearing computer. However, with this

new trend, the computer will actually not disappear, it will be everywhere. Embedded

systems provide a major part of the necessary technology. Embedded systems are

information processing systems that are embedded into a larger product and that are

normally not directly visible to the user. Examples of embedded systems include


9/56

9

information processing systems in telecommunication equipment, in transportation

systems, in fabrication equipment and in consumer electronics.

1.2Common characteristics of embedded system

Frequently, embedded systems are connected to the physical environment through

sensors collecting information about that environment and actuators1 controlling that

environment. Embedded systems have to be dependable. Many embedded systems are

safety-critical and therefore have to be dependable. Nuclear power plants are an example

of extremely safety-critical systems that are at least partially controlled by software.

Dependability is, however, also important in other systems, such as cars, trains, airplanes

etc. A key reason for being safety-critical is that these systems are directly connected to

the environment and have an immediate impact on the environment. Dependability

encompasses the following aspects of a system:

1. Reliability: Reliability is the probability that a system will not fail.

2. Maintainability: Maintainability is the probability that a failing system can be

repaired within a certain time-frame.

3. Availability: Availability is the probability that the system is available. Both the

reliability and the maintainability must be high in order to achieve a high

availability.

4. Safety: This term describes the property that a failing system will not cause any

harm.

5. Security: This term describes the property that confidential data remains

confidential and that authentic communication is guaranteed. Embedded systems

have to be efficient.

The following metrics can be used for evaluating the efficiency of embedded systems:


10/56

10

1. Energy: Many embedded systems are mobile systems obtaining their energy

through batteries. According to forecasts [SEMATECH, 2003], battery

technology will improve only at a very slow rate. However, computational

requirements are increasing at a rapid rate (especially for multimedia applications)

and customers are expecting long run-times from their batteries. Therefore, the

available electrical energy must be used very efficiently.

2. Code-size: All the code to be run on an embedded system has to be stored with

the system. Typically, there are no hard discs on which code can be stored.

Dynamically adding additional code is still an exception and limited to cases such

as Java-phones and set-top boxes. Due to all the other constraints, this means that

the code-size should be as small as possible for the intended application. If the

instruction memory is to be integrated onto this chip, it should be used very

efficiently.

3. Run-time efficiency: The minimum amount of resources should be used for

implementing the required functionality. We should be able to meet time

constraints using the least amount of hardware resources and energy. In order to

reduce the energy consumption, clock frequencies and supply voltages should be

as small as possible. Also, only the necessary hardware components should be

present.

4. Weight: All portable systems must be of low weight. Low weight is frequently an

important argument for buying a certain system.

5. Cost: For high-volume embedded systems, especially in consumer electronics,

competitiveness on the market is an extremely crucial issue, and efficient use of

hardware components and the software development budget are required. These

systems are dedicated towards a certain application. For example, processors

running control software in a car or a train will always run that software, and there

will be no attempt to run a computer game or spreadsheet program on the same

processor. There are mainly two reasons for this:

1. Running additional programs would make those systems less dependable.

2. Running additional programs is only feasible if resources such as memory are

unused. No unused resources should be present in an efficient system.


11/56

11

Most embedded systems do not use keyboards, mice and large computer monitors for

their user-interface. Instead, there is a dedicated user-interface consisting of push-buttons,

steering wheels, pedals etc. Because of this, the user hardly recognizes that information

processing is involved. Due to this, the new era of computing has also been characterized

by the disappearing computer.

Many embedded systems must meet real-time constraints. Not completing computations

within a given time-frame can result in a serious loss of the quality provided by the

system (for example, if the audio or video quality is affected) or may cause harm to the

user (for example, if cars, trains or planes do not operate in the predicted way). Many of

todays information processing systems are using techniques forspeeding-up information

processing on the average. For example, caches improve the average performance of a

system. In other cases, reliable communication is achieved by repeating certain

transmissions. For example, Internet protocols typically rely on resending messages in

case the original messages have been lost. On the average, such repetitions result in a

small loss of performance, even though for a certain message

the communication delay can be orders of magnitude larger than the normal delay. Many

embedded systems are hybrid systems in the sense that they include analog and digital

parts. Analog parts use continuous signal values in continuous time, whereas digital parts

use discrete signal values in discrete time.

Typically, embedded systems are reactive systems. They can be defined as follows: A

reactive system is one that is in continual interaction with its environment and executes at

a pace determined by that environment. Real embedded systems are very complex and

hence difficult to teach. Due to this set of common characteristics, it does make sense to

analyze common approaches for designing embedded systems, instead of looking at the

different application areas only in isolation. Embedded system is Information

processing system meeting most of the characteristics listed above. Most of the

characteristics of embedded systems can also be found in a recently introduced type of

computing: pervasive computing, also called ambient intelligence. The key goal of this

type of computing is to make information available anytime, anywhere.


12/56

12

Figure 1.1.2 Influence of embedded systems on ubiquitous computing

1.3 Application areas

The following list comprises key areas in which embedded systems are used:

1. Automotive electronics: Modern cars can be sold only if they contain a significant

amount of electronics. These include air bag control systems, engine control

systems, anti-braking systems (ABS), air-conditioning, GPS systems, safety

features, etc

2. Aircraft electronics: A significant amount of the total value of airplanes is due to

the information processing equipment, including flight control systems, anti-

collision systems, pilot information systems, and others.

3. Trains: For trains, the situation is similar to cars and airplanes. Safety features

contribute significantly to the total value of trains, and dependability is extremely

important.

4. Telecommunication: Mobile phones have been one of the fastest growing markets

in the recent years. For mobile phones, radio frequency (RF) design, digital signal

processing and low power design are key aspects.

5. Medical systems: There is a huge potential for improving the medical service by

taking advantage of information processing taking place within medical

equipment.


13/56

13

6. Military applications: Information processing has been used in military equipment

for many years. Some of the very first computers analyzed military radar signals.

7. Authentication systems: Embedded systems can be used for authentication

purposes. For example, advanced payment systems can provide more security

than classical systems. The SMART pen is an example of such an advanced

payment system. The SMART pen is a pen-like instrument analyzing physical

parameters while its user is signing. Physical parameters include the tilt, force and

acceleration. These values are transmitted to a host PC and compared with

information available about the user. As a result, it can be checked if both the

image of the signature as well as the way it has been produced coincide with the

stored information. Other authentication systems include finger print sensors or

face recognition systems. Consumer electronics: Video and audio equipment is a

very important sector of the electronics industry. The information processing

integrated

into such equipment is steadily growing. New services and better quality are

implemented using advanced digital signal processing techniques Many TV sets,

multimedia phones, and game consoles comprise high performance processors

and memory systems. They represent special cases of embedded systems.

Fabrication equipment: Fabrication equipment is a very traditional area in which

embedded systems have been employed for decades. Safety is very important for such

systems, the energy consumption is less a problem. As an example, fig. 1.3 (taken from

Kopetz [Kopetz, 1997]) shows a container connected to a pipe. The pipe includes a valve

and a sensor. Using the readout from the sensor, a computer may have to control the

amount of liquid leaving the pipe. Figure1.3. Controlling a valve. The valve is an

example of an actuator.

Smart buildings: Information processing can be used to increase the comfort level in

buildings, can reduce the energy consumption within buildings, and can improve safety

and security. Subsystems which traditionally were unrelated have to be connected for this

purpose. There is a trend towards integrating air-conditioning, lighting, access control,

accounting and distribution


14/56

14

of information into a single system. For example, energy can be saved on cooling,

heating and lighting of rooms which are empty. Available ooms can be displayed at

appropriate places, simplifying ad-hoc meetings and cleaning. Air condition noise can be

reduced to a level required for the actual operating conditions. Intelligent usage of blinds

can optimize lighting and air-conditioning. Tolerance levels of air conditioning

subsystems can be increased for empty rooms, and the lighting can be automatically

reduced. Lists of non-empty rooms can be displayed at the entrance of the building in

emergency situations. Initially, such systems will mostly be present only in high-tech

office buildings.

Robotics: Robotics is also a traditional area in which embedded systems have been used.

Mechanical aspects are very important for robots. Most of the characteristics described

above also apply to robotics. Recently, some new kinds of robots, modeled after animals

or human beings, have been designed.

This set of examples demonstrates the huge variety of embedded systems. Why does it

make sense to consider all these types of embedded systems in one book? It makes sense

because information processing in these systems has many common characteristics,

despite being physically so different. Fig 1.3 Growing importance of embedded systems

The size of the embedded system market can be analyzed from a variety of perspectives.

Looking at the number of processors that are currently used, it has been estimated that

about 79% of all the processors are used in embedded systems2. Many of the embedded

processors are 8-bit processors, but despite this, 75% of all 32-bit processors are

integrated into embedded systems [Stiller,

2000]. Already in 1996, it was estimated that the average American came into contact

with 60 microprocessors per day [Camposano and Wolf, 1996]. Some high-end cars

contain more than 100 processors3. These numbers are much larger than what is typically

expected, since most people do not realize that they are using processors. The importance

of embedded systems was also stated by journalist Mary Ryan [Ryan, 1995]:

...embedded chips form the backbone of the electronics driven world in which we live.

...they are part of almost everything that runs on electricity According to quite a number

of forecasts, the embedded system market will soon be much larger than the market for

PC-like systems. Also, the amount of software used in embedded systems is expected to


15/56

15

increase. According to Vaandrager, for many products in the area of consumer electronics

the amount of code is doubling every two years [Vaandrager, 1998] Embedded systems

form the basis of the so-called post-PC era, in which information processing is more and

more moving away from just PCs to embedded systems.

The growing number of applications results in the need for design technologies

supporting the design of embedded systems. Currently available technologies and tools

still have important limitations. For example, there is still a need for better specification

languages, tools generating implementations from specifications, timing verifiers, real-

time operating systems, low-power design techniques, and design techniques for

dependable systems.

Now a days electronics have developed at very fast rate. It plays a major role in the life

of human being and makes it very easy and comfortable. Electronics circuits are designed

to obtain a particular function. For this purpose a no of electronic component are suitably

connected. Embedded systems have proved changing face of today's industrial scenario.

An embedded system is a system is a special-purposecomputer system designed to

perform one or a few dedicated functions often withreal-time computing constraints. It is

usually embedded as part of a complete device including hardware and mechanical parts.

In contrast, a general-purpose computer, such as apersonal computer, can do many

different tasks depending on programming.

Embedded systems control many of the common devices in use today. Fuelling in

unbridled power into industrial computers to tackle the most complex applications, they

have made quite an impression with a lot of the leading industrial sectors. Backed with

the most durable components and peripherals sticking to the highest quality standards, the

next generation embedded computers have what it takes to endure highly trying and harsh

work environments. Multifunctional ability is the highlight of these systems even as they

comprise a uniquely designed combination of software and hardware to perform highly

challenging tasks that are a far cry for the common personal computers. This combination

happens to be a programmed platform that is assigned with specific applications for the

task and goes through various tests to make sure the systems offer long-life performance.

Embedded systems range from portable devices such as digital watches and MP3 players,

to large stationary installations like traffic lights, factory controllers, or be a crucial
http://en.wikipedia.org/wiki/Computerhttp://en.wikipedia.org/wiki/Real-time_computinghttp://en.wikipedia.org/wiki/Personal_computerhttp://en.wikipedia.org/wiki/Personal_computerhttp://en.wikipedia.org/wiki/Real-time_computinghttp://en.wikipedia.org/wiki/Computer


16/56

16

contributor systems controlling nuclear power plants. Complexity varies from low, with

a single microcontroller chip, to very high with multiple units, peripherals and networks

mounted inside a large chassis or enclosure. Embedded computers serve their purpose in

a variety of areas, like the gaming industry, military, security and surveillance, and

infotainment. Talking of their abilities and efficiency, a look into the highly popular

CorBrick855E embedded computer will offer a good insight into what is possible at their

behest

EXAMPLES OF EMBEDDED SYSTEM:

Automated tiller machines (ATMS).

Cellular telephones and telephonic switches.

Computer network equipment, including routers timeservers and firewalls

Computer printers, Copiers.

Disk drives (floppy disk drive and hard disk drive)

Engine controllers and antilock brake controllers for automobiles.

Home automation products like thermostat, air conditioners sprinkles and security

monitoring system.

House hold appliances including microwave ovens, washing machines, TV sets

DVD players/recorders.

Medical equipment.

Measurement equipment such as digital storage oscilloscopes, logic analyzers and

spectrum analyzers.

Multimedia appliances: internet radio receivers, TV set top boxes.

Stationary video game controllers.


17/56

17

Chapter 2ATMEL AVR


18/56

18

2.1 Introduction

The AVRis amodified Harvard architecture8-bitRISC single

chipmicrocontroller which was developed byAtmel in 1996. The AVR was one of the

first microcontroller families to use on-chipflash memory for program storage, as

opposed toone-time programmable ROM,EPROM,orEEPROM used by other

microcontrollers at the time.

2.2 Brief history

The AVR architecture was conceived by two students at theNorwegian Institute of

Technology (NTH) Alf-Egil BogenBlog (www.alfbogen.com) and Vegard Wollan.

The original AVR MCU was developed at a localASIC house inTrondheim,

Norway called Nordic VLSI at the time, nowNordic Semiconductor,where Bogen and

Wollan were working as students. It was known as a RISC (Micro RISC) and was

available as silicon IP/building block from Nordic VLSI. When the technology was sold

to Atmel from Nordic VLSI, the internal architecture was further developed by Bogen

and Wollan at Atmel Norway, a subsidiary of Atmel. The designers worked closely with

compiler writers atIAR Systems to ensure that the instruction set provided for moreefficientcompilation ofhigh-level languages.Atmel says that the name AVR is not an

acronym and does not stand for anything in particular. The creators of the AVR give no

definitive answer as to what the term "AVR" stands for. However, it is commonly

accepted that AVR stands for Alf (Egil Bogen) andVegard (Wollan)'s RISC processor.

Note that the use of "AVR" in this article generally refers to the 8-bit RISC line of Atmel

AVR Microcontrollers.

Among the first of the AVR line was the AT90S8515, which in a 40-pin DIP package has

the same pinout as an8051 microcontroller, including the external multiplexed address

and data bus. The polarity of the RESET line was opposite (8051's having an active-high

RESET, while the AVR has an active-low RESET), but other than that, the pinout was

identical.
http://en.wikipedia.org/wiki/Modified_Harvard_architecturehttp://en.wikipedia.org/wiki/8-bithttp://en.wikipedia.org/wiki/Reduced_instruction_set_computerhttp://en.wikipedia.org/wiki/Microcontrollerhttp://en.wikipedia.org/wiki/Atmelhttp://en.wikipedia.org/wiki/Flash_memoryhttp://en.wikipedia.org/wiki/Programmable_read-only_memoryhttp://en.wikipedia.org/wiki/EPROMhttp://en.wikipedia.org/wiki/EEPROMhttp://en.wikipedia.org/wiki/Norwegian_Institute_of_Technologyhttp://en.wikipedia.org/wiki/Norwegian_Institute_of_Technologyhttp://www.alfbogen.com/http://en.wikipedia.org/wiki/Application-specific_integrated_circuithttp://en.wikipedia.org/wiki/Trondheim,_Norwayhttp://en.wikipedia.org/wiki/Trondheim,_Norwayhttp://en.wikipedia.org/wiki/Nordic_Semiconductorhttp://en.wikipedia.org/wiki/IAR_Systemshttp://en.wikipedia.org/wiki/Compilerhttp://en.wikipedia.org/wiki/High-level_programming_languagehttp://en.wikipedia.org/wiki/Intel_8051http://en.wikipedia.org/wiki/Intel_8051http://en.wikipedia.org/wiki/High-level_programming_languagehttp://en.wikipedia.org/wiki/Compilerhttp://en.wikipedia.org/wiki/IAR_Systemshttp://en.wikipedia.org/wiki/Nordic_Semiconductorhttp://en.wikipedia.org/wiki/Trondheim,_Norwayhttp://en.wikipedia.org/wiki/Trondheim,_Norwayhttp://en.wikipedia.org/wiki/Application-specific_integrated_circuithttp://www.alfbogen.com/http://en.wikipedia.org/wiki/Norwegian_Institute_of_Technologyhttp://en.wikipedia.org/wiki/Norwegian_Institute_of_Technologyhttp://en.wikipedia.org/wiki/EEPROMhttp://en.wikipedia.org/wiki/EPROMhttp://en.wikipedia.org/wiki/Programmable_read-only_memoryhttp://en.wikipedia.org/wiki/Flash_memoryhttp://en.wikipedia.org/wiki/Atmelhttp://en.wikipedia.org/wiki/Microcontrollerhttp://en.wikipedia.org/wiki/Reduced_instruction_set_computerhttp://en.wikipedia.org/wiki/8-bithttp://en.wikipedia.org/wiki/Modified_Harvard_architecture


19/56

19

2.3 Device overview

The AVR is a modifiedHarvard architecture machine where program and data are stored

in separate physical memory systems that appear in different address spaces, but having

the ability to read data items from program memory using special instructions.

2.4 Basic families

AVRs are generally classified into six broad groups:

tinyAVRtheATtiny series

0.516 kB program memory

632-pin package

Limited peripheral set

megaAVRthe ATmega series

4512 kB program memory

28100-pin package

Extended instruction set (multiply instructions and instructions for handling

larger program memories)

Extensive peripheral set

XMEGAthe ATxmega series

16384 kB program memory

4464100-pin package (A4, A3, A1)

Extended performance features, such as DMA, "Event System", and

cryptography support.

Extensive peripheral set withADCs

Application-specific AVR

megaAVRs with special features not found on the other members of the AVR

family, such as LCD controller,USB controller, advanced PWM, CAN, etc.

FPSLIC (AVR with FPGA)

FPGA 5K to 40K gates
http://en.wikipedia.org/wiki/Harvard_architecturehttp://en.wikipedia.org/wiki/Atmel_AVR_ATtiny_comparison_charthttp://en.wikipedia.org/wiki/Analog-to-digital_converterhttp://en.wikipedia.org/wiki/Universal_Serial_Bushttp://en.wikipedia.org/wiki/Field-programmable_gate_arrayhttp://en.wikipedia.org/wiki/Field-programmable_gate_arrayhttp://en.wikipedia.org/wiki/Universal_Serial_Bushttp://en.wikipedia.org/wiki/Analog-to-digital_converterhttp://en.wikipedia.org/wiki/Atmel_AVR_ATtiny_comparison_charthttp://en.wikipedia.org/wiki/Harvard_architecture


20/56

20

SRAM for the AVR program code, unlike all other AVRs

AVR core can run at up to 50 MHz

32-bit AVRs

In 2006 Atmel released microcontrollers based on the new, 32-

bit,AVR32 architecture. They includeSIMD andDSP instructions, along with

other audio and video processing features. This 32-bit family of devices is

intended to compete with theARMbased processors. The instruction set is

similar to other RISC cores, but it is not compatible with the original AVR or any

of the various ARM cores.

2.5 Device architecture

Flash,EEPROM,andSRAM are all integrated onto a single chip, removing the need

for external memory in most applications. Some devices have a parallel external bus

option to allow adding additional data memory or memory-mapped devices. Almost

all devices (except the smallest TinyAVR chips) have serial interfaces, which can be

used to connect larger serial EEPROMs or flash chips.

2.6 Program memory

Program instructions are stored innon-volatileflash memory.Although the MCUs

are 8-bit, each instruction takes one or two 16-bit words.

The size of the program memory is usually indicated in the naming of the device

itself (e.g., the ATmega64x line has 64 kB of flash while the ATmega32x line has

32 kB).

There is no provision for off-chip program memory; all code executed by the AVR

core must reside in the on-chip flash. However, this limitation does not apply to the

AT94 FPSLIC AVR/FPGA chips.
http://en.wikipedia.org/wiki/AVR32http://en.wikipedia.org/wiki/SIMDhttp://en.wikipedia.org/wiki/Digital_signal_processorhttp://en.wikipedia.org/wiki/ARM_architecturehttp://en.wikipedia.org/wiki/Flash_memoryhttp://en.wikipedia.org/wiki/EEPROMhttp://en.wikipedia.org/wiki/Static_random-access_memoryhttp://en.wikipedia.org/wiki/Non-volatilehttp://en.wikipedia.org/wiki/Flash_memoryhttp://en.wikipedia.org/wiki/Flash_memoryhttp://en.wikipedia.org/wiki/Non-volatilehttp://en.wikipedia.org/wiki/Static_random-access_memoryhttp://en.wikipedia.org/wiki/EEPROMhttp://en.wikipedia.org/wiki/Flash_memoryhttp://en.wikipedia.org/wiki/ARM_architecturehttp://en.wikipedia.org/wiki/Digital_signal_processorhttp://en.wikipedia.org/wiki/SIMDhttp://en.wikipedia.org/wiki/AVR32


21/56

21

2.7 Internal data memory

The dataaddress space consists of theregister file,I/O registers, andSRAM.

The AVRs have 32single-byteregisters and are classified as 8-bit RISC devices.

In most variants of the AVR architecture, the working registers are mapped in as the

first 32 memory addresses (000016001F16) followed by the 64 I/O registers (002016

005F16).

Actual SRAM starts after these register sections (address 006016). (Note that the I/O

register space may be larger on some more extensive devices, in which casethememory mapped I/O registers will occupy a portion of the SRAM address space.)

Even though there are separate addressing schemes and optimized opcodes for

register file and I/O register access, all can still be addressed and manipulated as if

they were in SRAM.

In the XMEGA variant, the working register file is not mapped into the data address

space; as such, it is not possible to treat any of the XMEGA's working registers as

though they were SRAM. Instead, the I/O registers are mapped into the data address

space starting at the very beginning of the address space. Additionally, the amount ofdata address space dedicated to I/O registers has grown substantially to 4096 bytes

(0000160FFF16). As with previous generations, however, the fast I/O manipulation

instructions can only reach the first 64 I/O register locations (the first 32 locations for

bitwise instructions). Following the I/O registers, the XMEGA series sets aside a

4096 byte range of the data address space which can be used optionally for mapping

the internal EEPROM to the data address space (1000161FFF16). The actual SRAM

is located after these ranges, starting at 200016.

2.8 EEPROM

Almost all AVR microcontrollers have internalEEPROM for semi-permanent data

storage. Like flash memory, EEPROM can maintain its contents when electrical

power is removed.
http://en.wikipedia.org/wiki/Address_spacehttp://en.wikipedia.org/wiki/Register_filehttp://en.wikipedia.org/wiki/Static_random-access_memoryhttp://en.wikipedia.org/wiki/Bytehttp://en.wikipedia.org/wiki/Processor_registerhttp://en.wikipedia.org/wiki/Memory-mapped_I/Ohttp://en.wikipedia.org/wiki/EEPROMhttp://en.wikipedia.org/wiki/EEPROMhttp://en.wikipedia.org/wiki/Memory-mapped_I/Ohttp://en.wikipedia.org/wiki/Processor_registerhttp://en.wikipedia.org/wiki/Bytehttp://en.wikipedia.org/wiki/Static_random-access_memoryhttp://en.wikipedia.org/wiki/Register_filehttp://en.wikipedia.org/wiki/Address_space


22/56

22

In most variants of the AVR architecture, this internal EEPROM memory is not

mapped into the MCU's addressable memory space. It can only be accessed the same

way an external peripheral device is, using special pointer registers and read/write

instructions which makes EEPROM access much slower than other internal RAM.

However, some devices in the SecureAVR (AT90SC) family use a special EEPROM

mapping to the data or program memory depending on the configuration. The

XMEGA family also allows the EEPROM to be mapped into the data address space.

Since the number of writes to EEPROM is not unlimitedAtmel specifies 100,000

write cycles in their datasheetsa well designed EEPROM write routine should

compare the contents of an EEPROM address with desired contents and only perform

an actual write if the contents need to be changed.

Note that erase and write can be performed separately in many cases, byte-by-byte,which may also help prolong life when bits only need to be set to all 1s (erase) or

selectively cleared to 0s (write).

2.9 Program execution

Atmel's AVRs have a two stage, single levelpipeline design. This means the next

machine instruction is fetched as the current one is executing. Most instructions take

just one or two clock cycles, making AVRs relatively fast among theeight-

bit microcontrollers.

The AVR processors were designed with the efficient execution ofcompiledC code

in mind and have several built-in pointers for the task.

2.10 Instruction set

TheAVR instruction set is moreorthogonal than those of most eight-bit

microcontrollers, in particular the8051 clones andPIC microcontrollers with which

AVR competes today. However, it is not completely regular:

Pointer registers X, Y, and Z have addressing capabilities that are different from

each other.
http://en.wikipedia.org/wiki/Pipeline_(computing)http://en.wikipedia.org/wiki/Eight-bithttp://en.wikipedia.org/wiki/Eight-bithttp://en.wikipedia.org/wiki/Compilerhttp://en.wikipedia.org/wiki/C_(programming_language)http://en.wikipedia.org/wiki/Atmel_AVR_instruction_sethttp://en.wikipedia.org/wiki/Orthogonal_instruction_sethttp://en.wikipedia.org/wiki/Intel_8051http://en.wikipedia.org/wiki/PIC_microcontrollerhttp://en.wikipedia.org/wiki/Pointer_registerhttp://en.wikipedia.org/wiki/Pointer_registerhttp://en.wikipedia.org/wiki/PIC_microcontrollerhttp://en.wikipedia.org/wiki/Intel_8051http://en.wikipedia.org/wiki/Orthogonal_instruction_sethttp://en.wikipedia.org/wiki/Atmel_AVR_instruction_sethttp://en.wikipedia.org/wiki/C_(programming_language)http://en.wikipedia.org/wiki/Compilerhttp://en.wikipedia.org/wiki/Eight-bithttp://en.wikipedia.org/wiki/Eight-bithttp://en.wikipedia.org/wiki/Pipeline_(computing)


23/56

23

Register locations R0 to R15 have different addressing capabilities than register

locations R16 to R31.

I/O ports 0 to 31 have different addressing capabilities than I/O ports 32 to 63.

CLR affects flags, while SER does not, even though they are complementary

instructions. CLR set all bits to zero and SER sets them to one. (Note that CLR is

pseudo-op for EOR R, R; and SER is short for LDI R,$FF. Math operations such

as EOR modify flags while moves/loads/stores/branches such as LDI do not.)

Accessing read-only data stored in the program memory (flash) requires special

LPM instructions; the flash bus is otherwise reserved for instruction memory.

Additionally, some chip-specific differences affect code generation. Code pointers

(including return addresses on the stack) are two bytes long on chips with up to 128

kBytes of flash memory, but three bytes long on larger chips; not all chips have

hardware multipliers; chips with over 8 kBytes of flash have branch and call

instructions with longer ranges; and so forth.

The mostly regular instruction set makes programming it using C (or even Ada)

compilers fairly straightforward.GCC has included AVR support for quite some

time, and that support is widely used. In fact, Atmel solicited input from major

developers of compilers for small microcontrollers, to determine the instruction set

features that were most useful in a compiler for high-level languages.

2.11 MCU speed

The AVR line can normally support clock speeds from 0 to 20 MHz, with some

devices reaching 32 MHz. Lower powered operation usually requires a reduced clock

speed. All recent (Tiny, Mega, and Xmega, but not 90S) AVRs feature an on-chip

oscillator, removing the need for external clocks or resonator circuitry. Some AVRs

also have a system clock prescaler that can divide down the system clock by up to

1024. This prescaler can be reconfigured by software during run-time, allowing the

clock speed to be optimized.

Since all operations (excluding literals) on registers R0 - R31 are single cycle, the

AVR can achieve up to 1MIPSper MHz, i.e. an 8 MHz processor can achieve up to

8 MIPS. Loads and stores to/from memory take two cycles, branching takes two
http://en.wikipedia.org/wiki/Processor_registerhttp://en.wikipedia.org/wiki/GNU_Compiler_Collectionhttp://en.wikipedia.org/wiki/Million_instructions_per_secondhttp://en.wikipedia.org/wiki/Million_instructions_per_secondhttp://en.wikipedia.org/wiki/GNU_Compiler_Collectionhttp://en.wikipedia.org/wiki/Processor_register


24/56

24

cycles. Branches in the latest "3-byte PC" parts such as ATmega2560 are one cycle

slower than on previous devices.

2.12 Development

AVRs have a large following due to the free and inexpensive development tools

available, including reasonably priced development boards and free development

software. The AVRs are sold under various names that share the same basic core, but

with different peripheral and memory combinations. Compatibility between chips in

each family is fairly good, although I/O controller features may vary.

Seeexternal links for sites relating to AVR development.

2.13 Features

CurrentAVRs offer a wide range of features:

Multifunction, bi-directional general-purpose I/O ports with configurable, built-

inpull-up resistors

Multiple internal oscillators, including RC oscillator without external parts

Internal, self-programmable instructionflash memory up to 256 kB (384 kB on

XMega)

In-system programmable using serial/parallel low-voltage proprietary

interfaces orJTAG

Optional boot code section with independent lock bits for protection

On-chip debugging (OCD) support through JTAG ordebugWIRE on most

devices

The JTAG signals (TMS, TDI, TDO, and TCK) are multiplexed on GPIOs.

These pins can be configured to function as JTAG or GPIO depending on the

setting of a fuse bit, which can be programmed via ISP or HVSP. By default,

AVRs with JTAG come with the JTAG interface enabled.

debugWIRE uses the /RESET pin as a bi-directional communication channel

to access on-chip debug circuitry. It is present on devices with lower pin

counts, as it only requires one pin.
http://en.wikipedia.org/wiki/Atmel_AVR#External_linkshttp://en.wikipedia.org/wiki/Pull-up_resistorhttp://en.wikipedia.org/wiki/Flash_memoryhttp://en.wikipedia.org/wiki/In-system_programminghttp://en.wikipedia.org/wiki/JTAGhttp://en.wikipedia.org/wiki/DebugWIREhttp://en.wikipedia.org/wiki/General_Purpose_Input/Outputhttp://en.wikipedia.org/wiki/DebugWIREhttp://en.wikipedia.org/wiki/DebugWIREhttp://en.wikipedia.org/wiki/General_Purpose_Input/Outputhttp://en.wikipedia.org/wiki/DebugWIREhttp://en.wikipedia.org/wiki/JTAGhttp://en.wikipedia.org/wiki/In-system_programminghttp://en.wikipedia.org/wiki/Flash_memoryhttp://en.wikipedia.org/wiki/Pull-up_resistorhttp://en.wikipedia.org/wiki/Atmel_AVR#External_links


25/56

25

Internal dataEEPROM up to 4 kB

InternalSRAM up to 16 kB (32 kB on XMega)

External 64 kB little endian data space on certain models, including the

Mega8515 and Mega162.

The external data space is overlaid with the internal data space, such that the

full 64 kB address space does not appear on the external bus and accesses to

e.g. address 010016will access internal RAM, not the external bus.

In certain members of the XMega series, the external data space has been

enhanced to support both SRAM and SDRAM. As well, the data addressing

modes have been expanded to allow up to 16 MB of data memory to be

directly addressed.

AVRs generally do not support executing code from external memory.

SomeASSPs using the AVR core do support external program memory.

8-bit and 16-bit timers

PWM output (some devices have an enhanced PWM peripheral which

includes a dead-time generator)

Input capture that record a time stamp triggered by a signal edge

Analog comparator

10 or 12-bitA/D converters,with multiplex of up to 16 channels

12-bitD/A converters

A variety of serial interfaces, including IC compatible Two-Wire Interface (TWI)

Synchronous/asynchronous serial peripherals (UART/USART) (used

withRS-232,RS-485,and more)

Serial Peripheral Interface Bus (SPI)

Universal Serial Interface (USI) for two or three-wire synchronous data

transfer

Brownout detection

Watchdog timer (WDT) Multiple power-saving sleep modes

Lighting and motor control (PWM-specific) controller models

CAN controller support

USB controller support
http://en.wikipedia.org/wiki/EEPROMhttp://en.wikipedia.org/wiki/Static_random-access_memoryhttp://en.wikipedia.org/wiki/Application-specific_standard_producthttp://en.wikipedia.org/wiki/Pulse-width_modulationhttp://en.wikipedia.org/wiki/Input_capturehttp://en.wikipedia.org/wiki/Analog-to-digital_converterhttp://en.wikipedia.org/wiki/Digital-to-analog_converterhttp://en.wikipedia.org/wiki/I%C2%B2Chttp://en.wikipedia.org/wiki/Universal_asynchronous_receiver/transmitterhttp://en.wikipedia.org/wiki/RS-232http://en.wikipedia.org/wiki/RS-485http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bushttp://en.wikipedia.org/wiki/Brownout_(electricity)http://en.wikipedia.org/wiki/Watchdog_timerhttp://en.wikipedia.org/wiki/Pulse-width_modulationhttp://en.wikipedia.org/wiki/Controller_area_networkhttp://en.wikipedia.org/wiki/Universal_Serial_Bushttp://en.wikipedia.org/wiki/Universal_Serial_Bushttp://en.wikipedia.org/wiki/Controller_area_networkhttp://en.wikipedia.org/wiki/Pulse-width_modulationhttp://en.wikipedia.org/wiki/Watchdog_timerhttp://en.wikipedia.org/wiki/Brownout_(electricity)http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bushttp://en.wikipedia.org/wiki/RS-485http://en.wikipedia.org/wiki/RS-232http://en.wikipedia.org/wiki/Universal_asynchronous_receiver/transmitterhttp://en.wikipedia.org/wiki/I%C2%B2Chttp://en.wikipedia.org/wiki/Digital-to-analog_converterhttp://en.wikipedia.org/wiki/Analog-to-digital_converterhttp://en.wikipedia.org/wiki/Input_capturehttp://en.wikipedia.org/wiki/Pulse-width_modulationhttp://en.wikipedia.org/wiki/Application-specific_standard_producthttp://en.wikipedia.org/wiki/Static_random-access_memoryhttp://en.wikipedia.org/wiki/EEPROM


26/56

26

Proper full-speed (12 Mbit/s) hardware & Hub controller with embedded

AVR.

Also freely available low-speed (1.5 Mbit/s) (HID)bitbanging software

emulations

Ethernet controller support

LCD controller support

Low-voltage devices operating down to 1.8 V (to 0.7 V for parts with built-in

DCDC upconverter)

picoPower devices

DMA controllers and "event system" peripheral communication.

Fast cryptography support forAES andDES
http://en.wikipedia.org/wiki/Human_interface_devicehttp://en.wikipedia.org/wiki/Bit-banginghttp://en.wikipedia.org/wiki/Ethernethttp://en.wikipedia.org/wiki/Liquid_crystal_displayhttp://en.wikipedia.org/wiki/Direct_memory_accesshttp://en.wikipedia.org/wiki/Advanced_Encryption_Standardhttp://en.wikipedia.org/wiki/Data_Encryption_Standardhttp://en.wikipedia.org/wiki/Data_Encryption_Standardhttp://en.wikipedia.org/wiki/Advanced_Encryption_Standardhttp://en.wikipedia.org/wiki/Direct_memory_accesshttp://en.wikipedia.org/wiki/Liquid_crystal_displayhttp://en.wikipedia.org/wiki/Ethernethttp://en.wikipedia.org/wiki/Bit-banginghttp://en.wikipedia.org/wiki/Human_interface_device


27/56

27

2.14 Advantages

The Performance, Features, and Tools You Need to Succeed Maximizing Power

EfficiencyTo meet the tough requirements of today's applications, Atmel has built upon more than adecade of low power research to develop Atmel picoPower technology. picoPowerenables AVR microcontrollers to reduce power consumption in both sleep and activemode, and achieve the industry's lowest power consumption, with 500nA @ 1.8V withRTC running and 9 nA in power-down sleep mode.

A Complete Set of Tools to Streamline DevelopmentAtmel offers a high quality, easy-to-use tool chain for the full range of AVR families.Available for free, the Atmel AVR Studio development environment enables codedevelopment in C or assembly, simulation, and integrates seamlessly with Atmel starter

kits, programmers, debuggers, evaluation kits, and reference designs. The result is fasterdevelopment, a more productive development team, and rapid time to market.

Software Made EasyAtmel offers AVR software framework, a complete library of drivers and middlewareneeded to build an application. A common Application Protocol Interface (API) isprovided making it easy to port your software between different AVR microcontrollers.In addition, a large collection of application notes explains how to use all on-chipperipherals in an application.

Capacitive Touch

Atmel QTouch Library makes it simple for developers to embed capacitive-touchbutton, slider, and wheel functionality into general-purpose AVR microcontrollerapplications. The royalty-free QTouch Library provides several library files for eachdevice and supports different numbers of touch channels, enabling both flexibility andefficiency in touch applications. By selecting the library file supporting the exact numberof channels needed, developers can achieve a more compact and efficient code using lessRAM.

A Perfect Fit for Your ApplicationAtmel compliments its broad range of standard AVR microcontrollers with a growingportfolio of derivatives tailored to specific applications. Our expanding portfolio enables

you to support a wide range of applications and functions, including automotive, LCDdrivers, CAN networking, USB connectivity, motor control, lighting applications, batterymanagement single-chip, IEEE 802.15.4, ZigBee, Remote Access Control and more.

Removing Data Transfer BottlenecksThe DMA controller found in Atmel AVR XMEGA and Atmel AVR UC3 sets a newstandard for data transfer efficiency in microcontrollers. It allows efficient data transfersbetween peripherals and memories with minimal CPU intervention. The result is data


28/56

28

transfer rates of up to 33MBit/s per SPI and USART portwith only a 15% load on theCPU.

Peripheral IntelligenceAtmel SleepWalking technology in AVR XMEGA, AVR UC3, and Atmel megaAVR

devices adds intelligence to peripherals, enabling them to perform a basic range checkbefore they generate an interrupt to the CPU. Combined with power save modes, theautomatic range check can be applied to remove the need to wake up the CPU at regularintervals to check the environment. The intelligent peripherals will monitor theenvironment on their own, and only wake the CPU when there is a need for action.Because the CPU draws far more energy than a single peripheral, SleepWalking candramatically reduce power consumption.

Peripheral CooperationInefficient peripheral management can impact performance and increase powerconsumption. To overcome these issues, our peripheral event system lets peripherals send

signals (events) directly to other peripherals, bypassing the CPU. The result is short,predictable response times, reduced number of wakeups from sleep, and CPU resourcesfreed up for other tasks. The peripheral event system can also replace interrupt-drivendata transfer with event-triggered data transfer, to help reduce application powerconsumption and increase system performance.

Advanced Arithmetic PerformanceFor applications that demand high-end arithmetic performance, selected AVRmicrocontrollers feature an IEEE754 compliant Floating Point Unit (FPU). Thisintegrated component lets the microcontrollers perform arithmetic calculations ondecimal numbers in fewer clock cycles, with higher precision. The FPU helps enhance awide range of applications. Sensor data can be filtered or analyzed to suppress noise andcapture better-quality information, and audio data processed without loss of fidelity.

Integrated SecurityTo help safeguard sensitive information, some AVR microcontrollers include a high-performance encryption and decryption engine that supports 128-, 192- and 256-bit keylengths for AES and 56-bit key lengths for DES. These products are ideal for applicationsthat require on-the-fly encryption of high-speed communication streams.

Flash SecurityTo safeguard sensitive data, Atmel FlashVault code protection enables on-chip flash to bepartially programmed and locked, for secure on-chip storage of software intellectualproperty. FlashVault code protection can carry software such as a math library or anencryption algorithm to potentially untrustworthy environments where the rest of thesource code can be developed and debugged. All AVR microcontrollers contain lockmechanisms to prevent reading and copying the program stored in on-chip Flash.

The Power of Self-Programming FlashFor flexibility and scalability, support for self-programming Flash enables field upgrades


29/56

29

via any communication interface. It also lets customers perform encrypted fieldprogramming, reducing or completely eliminating risk of programming the wrong binary.Read-while-Write Flash support lets customers continue to run applications while anupgrade is in progress, to minimize downtime.


30/56

30

Chapter 3Interfacing


31/56

31

3.1 Interfacing With The Real World Devices

(Computer Science) a program that controls a display for the user (usually on a computer)

and that allows the user to interact with the system part of a system exposed to a user. In

general, the system can be any kind of system with which a user may interact at will,such as a mechanical system or a computer system. (Fluid, Electronic, Optic) One of

the important issues in micro-fluidics is the interfacing of all the elements. How to align

optical fibers? How to connect wires to the micro-device? How to introduce a sample into

the fluid channel? These are some of the questions, which have to be solved.

An interface is a set of commands or menus through which a user Communicates

with a program. A command-driven interface is one in which you enter commands. A

menu-driven interface is one in which you select command choices from various menus

displayed on the screen.

Interfacing is a common term for a variety of materials used on the unseen or "wrong"

side of fabrics in sewing. Interfacings can be used to stiffen or add body to fabric,

such as the interfacing used in shirt collars; to strengthen a certain area of the fabric,

for instance where buttonholes will be sewn; or to keep fabrics, particularly knit fabrics,

from stretching out of shape. Interfacings come in a variety of weights and stiffnesses

to suit different purposes.

3.2 User Interface

The user interface is the aggregate of means by which people (the users) Interact with a

particular machine, device, computer program or other complex tool (the system). The

user interface provides means of: * Input, allowing the users to control the system* &

Output, allowing the system to inform the users (also referred to as feedback). A good

user interface makes it easy for users to do what they want to do.

The junction between a user and a computer program. An interface is a set of

commands or menus through which a user communicates with a program. A

command driven interface is one in which you enter commands. A menu-driven interface

is one in which you select command choices from various menus displayed on the screen.

The user interface is one of the most important parts of any program because it


32/56

32

determines how easily you can make the program do what we want to. It is widely

accepted that the user interface can make a critical difference in the perceived utility

of a system regardless of the system's performance.

In other words, the physical means of communication between a person and a software

program or operating system. At its most basic, this is the exchange of typed statements

in English or a program-like set of commands. It is the method by which the human

operator communicates with the various database, system, and applications modules.

3.3 Efficiency of User Interface Design

Many technological innovations rely upon User Interface Design to elevate their

technical complexity to a usable product. Technology alone may not win user

acceptance and subsequent marketability. The User Experience, or how the user

experiences the end product, is the key to acceptance. And at is where User Interface

Design enters the design the process. While product engineers focus on the technology,

usability specialists focus on the user interface. For greatest efficiency and cost

effectiveness, this working relationship should be maintained from the start of a project to

its rollout.

When applied to computer software, User Interface Design is also known asHuman-Computer Interaction or HCI. While people often think of Interface Design in

terms of computers, it also refers to many products where the user interacts with controls

or displays. Military aircraft, vehicles, airports, audio equipment, and computer

peripherals, are a few products that extensively apply User Interface Design.

Optimized User Interface Design requires a systematic approach to the design process.

But, to ensure optimum performance, Usability testing is required. This empirical

testing permits nave users to provide data about what does work as anticipated and

what does not work. Only after the resulting repairs are made can a product be

deemed to have a user optimized interface. The importance of good User Interface

Design can be the difference between product acceptance and rejection in the

marketplace. If end-users feel it is not easy to learn, not easy to use, or too

cumbersome, an otherwise excellent product could fail. Good User Interface Design


33/56

33

can make a product easy to understand and use, which results in greater user

acceptance.

3.4 Interfacing LED With AVR

This AVR tutorial will discuss interfacing Light Emitting Diodes with Atmel's AVR

series of Microcontrollers. A LEDis an acronym for Light Emitting Diodeand is

basically a electronic device which emits light when an electric current flows through it.

General purpose LEDs used in digital circuits require around 75mA or less and so we

usually use resistors to limit the current flowing through the LED when it is connected

within a circuit as shown below. The resistance of the resistor is calculated using the well

known formula V=IR.

Interfacing a LED with a Microcontroller

AVR microcontrollers such as the ATMega8515 only supply a current of about 20mA

and so we can drive an LED directly from the microcontroller port eliminating the

resistor. In fact if a resistor is added the intensity of the LED will be low.

The figure below shows 8-LEDs connected to an ATMega8515 microcontroller. The

code that follows if downloaded to the microcontroller will blink the LEDs continuously.

Note that this code could work with other AVR microcontrollers such as the ATMega16,

ATmega32, ATTiny2313, etc.

Note:In order for the circuit to operate as describe the internal oscillator of the

ATMega8515 microcontroller must be program to run at 4MHz.

/*

* Written in AVR Studio 5* Compiler: AVR GNU C Compiler (GCC)* Author: AVR Tutorials* Website: www.AVR-Tutorials.com*/

#include
http://www.avr-tutorials.com/http://www.avr-tutorials.com/


34/56

34

#define F_CPU 4000000UL#include

int main(){

DDRC = 0xFF; // Configure port C as output

while(1){

PORTC = 0xFF; // Turn ON LEDs_delay_ms(250); // Wait 250msPORTC = 0x00; // Turn OFF LEDs_delay_ms(250); // Wail 250ms

}

return 0;}

3.5 SEVEN SEGMENT DISPLAY:

The Light Emitting Diode (LED), finds its place in many applications in this modern

electronic fields. One of them is the Seven Segment Display. Seven-segment displays

contains the arrangement of the LEDs in Eight (8) passion, and a Dot (.) with a

common electrode, lead (Anode or Cathode). The purpose of arranging it in that passion

is that we can make any number out of that by switching ON and OFF the particular

LED's. Here is the block diagram of the Seven Segment LED arrangement.


35/56

35

LEDs are basically of two types:

Common Cathode (CC):

All the 8 anode legs uses only one cathode, which is common.

Common Anode (CA):

The common leg for all the cathode is of Anode type.We are using common

anode(CA) 7-segment display.

Input: Common anode is connected to the high voltage = 5 VoltsThis AVR tutorial will discuss interfacing a Seven Segment Displaywith the

AVR 8-bits microcontrollers . A Seven Segment Display is just seven LEDs

arranged and packaged in a configuration shown in Fig 1and it is therefore

recommended to complete the tutorial onInterfacing LEDs with the AVR

Microcontrollers before going through this tutorial.

The seven LEDs in the seven segment display are labelled with the letters A, B,

C, D, E. Fand Gas indicated in Fig 2below. Some seven segment display may

include 1 or 2 additional LEDs which are used as decimal point(s).
http://www.avr-tutorials.com/interfacing/interfacing-leds-avr-microcontrollerhttp://www.avr-tutorials.com/interfacing/interfacing-leds-avr-microcontrollerhttp://www.avr-tutorials.com/interfacing/interfacing-leds-avr-microcontrollerhttp://www.avr-tutorials.com/interfacing/interfacing-leds-avr-microcontroller


36/56

36

Seven Segment Displays are mainly used to display numerical digits. The figure

below shows which LEDs to turn ONto display the digits 1, 2, 3, 4, 5 and 6. Other

numbers can be displayed by turning ON the appropriate LEDs.

A Seven Segment Display can also be used to display certain letters of thealphabet. The figure below gives the LEDs to turn ONto display A, F, H, L and P.

Interfacing a Seven Segment Display with a Microcontroller

The figure below shows a Seven Segment Display (LDS-C305RI) connected to

an ATMega16 microcontroller. Since the seven segment display consists of

LEDs it can be connected directly to the ATMega16 or other AVR

microcontrollers as shown in the schematic below and as discussed in

theInterfacing LEDs with the AVR Microcontrollers tutorial.

Important Note:In order for the circuit to operate as describe the internal

oscillator of the microcontroller must be program to run at 4MHz.

The code that follows if downloaded to the microcontroller will display

continuously the sequence 1, 2, 3, 4, A, C, E, F. Note that other microcontrollers

such as the ATMega8515 can be used to replace the ATMega16 but the

connections would have to be adjusted. For connection information for this seven

segment display please see theLDS-C305RI DataSheet.The video at the end ofthis page shows the circuit in operation when the code is downloaded to the

ATMega16 microcontroller.

/** numbers_letters.c* Written in AVR Studio 5* Compiler: AVR GNU C Compiler (GCC)** Created: 10/06/2011 05:31:57 PM* Author: AVR Tutorials

* Website: www.AVR-Tutorials.com*/

#include

#define F_CPU 4000000UL#include
http://www.avr-tutorials.com/interfacing/interfacing-leds-avr-microcontrollerhttp://www.avr-tutorials.com/sites/default/files/LDS-C305RI.pdfhttp://www.avr-tutorials.com/http://www.avr-tutorials.com/http://www.avr-tutorials.com/sites/default/files/LDS-C305RI.pdfhttp://www.avr-tutorials.com/interfacing/interfacing-leds-avr-microcontroller


37/56

37

int main(void){

DDRA = 0xFF; // Configure port B as output

while(1)

{ //TODO:: Please write your application code

PORTA = 0b00110000; // Display Number 1_delay_ms(1000); // Wait for 1sPORTA = 0b01011011; // Display Number 2_delay_ms(1000); // Wait for 1sPORTA = 0b01001111; // Display Number 3_delay_ms(1000); // Wait for 1sPORTA = 0b01100110; // Display Number 4_delay_ms(1000); // Wait for 1s

PORTA = 0b01110111; // Display Letter A_delay_ms(1000); // Wait for 1sPORTA = 0b00111001; // Display Letter C_delay_ms(1000); // Wait for 1sPORTA = 0b01111001; // Display Letter E_delay_ms(1000); // Wait for 1sPORTA = 0b01110001; // Display Letter F_delay_ms(1000); // Wait for 1s

}

return 0;}

3.6 Interfacing LCD with AVR

A liquid crystal display (LCD) is a thin, flat panel used for electronically displaying

information such as text, images, and moving pictures. Its uses include monitors for

computers, televisions, instrument panels, and other devices ranging from aircraft

cockpit displays, to every-day consumer devices such as video players, gaming

devices, clocks, watches, calculators, and telephones. Among its major features are its


38/56

38

lightweight construction, its portability, and its ability to be produced in much larger

screen sizes than are practical for the construction of cathode ray tube (CRT) display

technology. Its low electrical power consumption enables it to be used in battery-

powered electronic equipment. It is an electronically-modulated optical device made

up of any number of pixels filled with liquid crystals and arrayed in front of a light

source (backlight) orreflector to produce images in color or monochrome. The earliest

discoveries leading to the development of LCD technology date from 1888. By 2008,

worldwide sales of televisions with LCD screens had surpassed the sale of CRT units.

Fig3.1.2 Liquid crystal display (LCD)

The most commonly used LCDs found in the market today are 1 line,2 lines or 4

lines LCDs which have only one controller and support at most 80 characters ,

whereas LCDs supporting more than 80 characters make use of 2 HD44780

controllers. Most LCDs with 1 controller has 14 pins and LCDs with 2 controllers

have 16 pins.

LCD pin descriptions:

The LCD discussed in this section has 14 pins. The function of each pin is given in

table.
http://en.wikipedia.org/wiki/Battery_%28electricity%29http://en.wikipedia.org/wiki/Reflectorhttp://en.wikipedia.org/wiki/Reflectorhttp://en.wikipedia.org/wiki/Battery_%28electricity%29


39/56

39

Figure3.1.3 Pin description

1) Vcc & VEE: While Vcc provide +5V and ground, respectively, VEE is usedfor controlling LCD contrast.

2) RS register select: There are two very important registers inside the LCD.

The RS pin is used for their selection as follows:

If RS = 0, the instruction command code register is selected, allowing the

user to send a command such as clear display, cursor at home, etc.

If RS = 1 the data register is selected, allowing the user to send data to be

displayed on the LCD.

3) R/W input allows the user to write information to the LCD or read

information from it. R/W = 1 when reading; R/W =0 when writing.

4) EEnable: The enable pin is used by the LCD to latch information presented

to its data pins. When data is supplied to data pins, a high to low pulse must

be applied to this pin in order for the LCD to latch in the data present at the

data pins. This pulse must be a minimum of 450 ns wide.

5) D0 D7: The 8 bit data pins, D0 D7, are used to send information to the

LCD or read the contents of the LCDs internal registers.To display letters

and numbers, we send ASCII codes for the letters AZ, az, and numbers 0

9 to these pins while making RS = 1.There are also instructions command

codes that can be sent to the LCD to clear the display or force the cursor to

the home position or blink the cursor.


40/56

40

We also use RS = 0 to check the busy flag bit to see if the LCD is ready to receiveinformation. The busy flag is D7 and can be read when R/W =1 and RS = 0, as

follows: if R/W =1, RS =0. When D7 = 1(busy flag = 1), the LCD busy taking care

of internal operations and will not accept any new information. When D7 = 0, the LCD

is ready to receive new information. Note: It is recommended to check the busy flag

before writing any data to the LCD.

Data display: In LCD, one can put data at any location. The following shows address

locations and how they are accessed:

RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0

0 0 1 A A A A A A A

LCD addressing

DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0

Line 1(max.) 1 0 0 0 0 0 0 0

Line 1(min.) 1 0 1 0 0 1 1 1

Line 2(max.) 1 1 0 0 0 0 0 0

Line 2(min.) 1 1 1 0 0 1 1 1

The upper address range can go as high as 0100111 for 40 character-wide LCD

while for the 20 character-wide LCD it goes up to 010011 (19 decimal = 10011

binary). Notice that the upper range 0100111 (binary) = 39 decimal which

corresponds to locations 0 to 39 for the LCDs of 40*2 size.


41/56

41

Program:

#include "mega32.h"

#define rs 2 // defined portc.3 as register select pin

#define en 3 // defined portc.2 as enable pin

void delay(unsigned int ms);

void msdelay(unsigned int ms);

void lcd_cmd(unsigned char cmd);

void lcd_char(unsigned char data);

void lcd_string(unsigned char *dat);

void lcd_init();

void main(void){

DDRC = 0xff;

lcd_init();

lcd_cmd(080);

lcd_string(EmbeddedTutorials);

while (1)

{

}

}

void delay(unsigned int ms) // small delay function

{

unsigned int i,j;

for(i=0;i


42/56

42

}

void lcd_cmd(unsigned char cmd) // command function

{

unsigned char temp;

temp = cmd & 0xF0;

PORTC&=0x0F;

PORTC |= temp;

PORTC &= (~(1


43/56

43

delay(1);

PORTC &= (~(1


44/56

44

3.7 Interfacing of STEPPER MOTOR With AVR

Stepper motorspairs nicely with a smart device like a microcontroller to create precisedigitally controlled movements that has made possible many of modern gizmos around

us. For example a printer, scanner,plotters,fax, floppy drive (not so modern though!),

automatic industrial machines likeCNC (Computer numerically controlled) drills, laser

shows etc. Though to a naked eye the motor of stepper look no other than a DC motor but

the difference is that each step of a stepper motor is in control. For example a high speed

desktop printer when the paper moves forward, to anovice it seems like a motor is just

pushing the paper out but in reality the control board inside the printer request the motor

to move the paper exactly same amount that has been printed. This precise movement

keeps the next printed pixel in alignment with previously printed pixels.

The thing is that the stepper motors have certain amount of steps per full 360 degree

rotation (exact number depends on model) the controller can request the stepper to rotate

any number of steps. For example if you are making a robot, you want it to move exactly

as per your program. Like if you say go forward 100cm then rotate right 45 degrees and

move forward 50 cm. You cannot do this with DC Motors, because for it you need to

calculate the exact speed for DC motor and then use blind timing for movement. Say if

you happen to find out the your robot moves at 5cm per second then to move 100cm it

will require 20 second. So you keep the motor on for 20 second and expect that it has

moved 100cm. But this can prove failure if the speed of robot changes due to drop in

level of battery or some additional weight or simply due to an uneven terrain etc. So thismethod is not so trustworthy.epper motorspairs nicely with a smart device like a

microcontroller to create precise digitally controlled movements that has made possible

many of modern gizmos around us. For example a printer, scanner,plotters,fax, floppy

drive (not so modern though!), automatic industrial machines likeCNC (Computer

numerically controlled) drills, laser shows etc. Though to a naked eye the motor of

stepper look no other than a DC motor but the difference is that each step of a stepper

motor is in control. For example a high speed desktop printer when the paper moves

forward, to anovice it seems like a motor is just pushing the paper out but in reality the

control board inside the printer request the motor to move the paper exactly same amount

that has been printed. This precise movement keeps the next printed pixel in alignmentwith previously printed pixels.





http://store.extremeelectronics.co.in/Stepper-Motors/http://en.wikipedia.org/wiki/Plotterhttp://en.wikipedia.org/wiki/Numerical_controlhttp://en.wikipedia.org/wiki/Novicehttp://store.extremeelectronics.co.in/Stepper-Motors/http://en.wikipedia.org/wiki/Plotterhttp://en.wikipedia.org/wiki/Numerical_controlhttp://en.wikipedia.org/wiki/Novicehttp://en.wikipedia.org/wiki/Novicehttp://en.wikipedia.org/wiki/Numerical_controlhttp://en.wikipedia.org/wiki/Plotterhttp://store.extremeelectronics.co.in/Stepper-Motors/http://en.wikipedia.org/wiki/Novicehttp://en.wikipedia.org/wiki/Numerical_controlhttp://en.wikipedia.org/wiki/Plotterhttp://store.extremeelectronics.co.in/Stepper-Motors/


45/56

45



will require 20 second. So you keep the motor on for 20 second and expect that it has

moved 100cm. But this can prove failure if the speed of robot changes due to drop in

level of battery or some additional weight or simply due to an uneven terrain etc. So this

method is not so trustworthy.

Stepper motorspairs nicely with a smart device like a microcontroller to create precise

digitally controlled movements that has made possible many of modern gizmos around

us. For example a printer, scanner,plotters,fax, floppy drive (not so modern though!),

automatic industrial machines likeCNC (Computer numerically controlled) drills, laser

shows etc. Though to a naked eye the motor of stepper look no other than a DC motor but

the difference is that each step of a stepper motor is in control. For example a high speed

desktop printer when the paper moves forward, to anovice it seems like a motor is just

pushing the paper out but in reality the control board inside the printer request the motorto move the paper exactly same amount that has been printed. This precise movement

keeps the next printed pixel in alignment with previously printed pixels.








will require 20 second. So you keep the motor on for 20 second and expect that it hasmoved 100cm. But this can prove failure if the speed of robot changes due to drop in

level of battery or some additional weight or simply due to an uneven terrain etc. So this

method is not so trustworthy.

The second method is the use of stepper motors. Say you have a stepper motor of 7.5

degree per step (that means it move 7.5 degree for single step or their are 48 step in full

rotation) and their is a gear reduction of ratio of 1:75 then you can control the stepper

with an accuracy of 0.1 degree per steps! wow! that's really precise! Now if we assume

you have attached a wheel of radius 3.5 cm then you can control the liner motor of your

robot with an accuracy of 0.00611 cm (I leave the math on you). That's pretty decent. To

move the motor forward 100cm, you just need to step the motor 100/0.00611 times that is

16,366 times. Instead if you step it 16,202 times it will move 99cm. So now the bot is

pretty much in your control.
http://store.extremeelectronics.co.in/Stepper-Motors/http://en.wikipedia.org/wiki/Plotterhttp://en.wikipedia.org/wiki/Numerical_controlhttp://en.wikipedia.org/wiki/Novicehttp://en.wikipedia.org/wiki/Novicehttp://en.wikipedia.org/wiki/Numerical_controlhttp://en.wikipedia.org/wiki/Plotterhttp://store.extremeelectronics.co.in/Stepper-Motors/


46/56

46

In the same way PCBs are drilled at accurate position, SMT components placed

automatically at their desired location, pixel on a paper are printed. Below are some

videos that may help you get the point.

Types of stepper motor

Their are many types of stepper motors available but the two most common types are

Unipolar Stepper Motor- Has simple driver requirement. Less torque at same size andweight as compared to bipolar type.

Bipolar Stepper Motor- Has slightly complicated driver requirement. More torque atsame size and weight as compared to unipolar type.

Since the Unipolar type is simpler to drive we will start our journey with it.

Driving Stepper Motor with AVR MCU

In the figure below is shown a simplified construction of astepper motor.The center is a

permanent magnet(PM) rotor. Around it are four electromagnets. One end of all four

electromagnet is connected to a point called "common". The common is usually

connected to the stepper supply voltage (eg. 12v). The four coils are named A,B,C and D.

To rotate a stepper motor, coils are excited in turns like A,B,C,D. The rotor will try to

align itself with the currently exited coil. Lets say that the white point shown on rotor is

magnetic north pole. Also assume that when coils are excited, their inner end becomesmagnetic south. So the white point on rotor will try to align with the currently excited

coil.(As the opposite poles attract)

So to drive a stepper motor from AVR MCU you just need to excite the coils A,B,C,D in

turns to rotate the motor in anti clock wire direction. If you want to rotate the motor in

clock wise direction simply excite the coil in reverse order that is D,C,B,A.

As the port of AVR can only sink or source 20mA current approximately, they cannot be

used to drive the the coils directly. So we need some thing that can boost this current. The

part that fit perfectly in this scenario isULN2003A.It is a high voltage, high current

Darlington array. It can be driven directly with a TTL level input and the output cansource up to 500ma. Since it is array of sevendarlington pair,(of which we require only

four) it is much compact.

Program

#include
http://store.extremeelectronics.co.in/Stepper-Motors/http://www.google.co.in/url?sa=t&source=web&cd=1&ved=0CCcQFjAA&url=http%3A%2F%2Ffocus.ti.com%2Flit%2Fds%2Fsymlink%2Fuln2003a.pdf&rct=j&q=uln2003a&ei=PQ7VTaqbGsrRrQe1zenlCw&usg=AFQjCNHPVY6d7GoCKk_HY30XEpiPFh8FEg&cad=rjahttp://en.wikipedia.org/wiki/Darlington_transistorhttp://en.wikipedia.org/wiki/Darlington_transistorhttp://www.google.co.in/url?sa=t&source=web&cd=1&ved=0CCcQFjAA&url=http%3A%2F%2Ffocus.ti.com%2Flit%2Fds%2Fsymlink%2Fuln2003a.pdf&rct=j&q=uln2003a&ei=PQ7VTaqbGsrRrQe1zenlCw&usg=AFQjCNHPVY6d7GoCKk_HY30XEpiPFh8FEg&cad=rjahttp://store.extremeelectronics.co.in/Stepper-Motors/


47/56

47

#include

#include "xstepper.h"

voidmain()

{

//Initialize the stepper library

StepperInit();

_delay_loop_2(10000);

while(1)

{

for(uint16_t i=0;i


48/56

48

As mentioned in my previous blog post, I had recently given a workshop at the AIUB

along with my friend Omee. Due to time shortage, I could not finish my presentation on

ADCs. I wanted to share some of the materials that I studied here in my blog post.

In short the ADC converts the voltage level measured at a ADC channel pin to a

corresponding binary value. The converted value is stored in a 16 bit register ADC which

is divided into two segments: ADCH and ADCL.

Firstly, the ADC of the ATmega32, or most AVR microcontrollers is 10 bit. That means

there are 2^10 or 1024 levels detectable by this ADC which are uniformly spaced over

the region of the maximum and minimum voltage level. The minimum voltage is 0V, and

maximum is either Vcc or internally generated 2.56V.

Before using the ADC it must be preconfigured. The ADC has 8 channels, that can beselected from the ADMUX register. This is the structure of the ADMUX register:

The ADMUX register also has a ADLAR bit, which can Left Adjust or right adjust the

output of the ADC. This shows the effect of changing ADLAR bit value in ADC:

So depending on operation, if the least significant bits can be discarded, and not much

accuracy is needed, ADLAR=1 can be used and ADCH value can just be taken readily.

Also the reference voltage of ADC is selected by the REFS1 and REFS0 bits. It can be

used to select an externally generated Vref, as well as the 2.56V internally generatedvoltage.

For some other control of the ADCs, there are some extra registers: ADC Control and

Status Register. Funny thing is, the register structure is different in ATmega8 and

ATmega32, so while this post highlights only ATmega32 microcontroller, it is suggested

that you should always consult datasheet before writing your code for a specific

microcontroller.

The ADC can be configured to fire up automatically, so that it converts the value and at

the end of conversion, generates an interrupt. These settings are also in the control andstatus register

ADATE - ADC Auto Trigger Enable, if set it will automatically do the conversion based

on the triggering condition (discussed later)

ADIF - ADC Interrupt Flag


49/56

49

ADIE - ADC Interrupt Enable - Triggers Interrupt on completed conversion, works when

global interrupt is enabled.

ADPS2-0 - these select the clock frequency of the trigger after which the ADC is

triggered.

SFIOR Register (Also termed as ADCSRB in some microcontrollers) has the function

of setting the condition on which the ADC is triggered. For free running mode, it always

trigger at the specified clock cycle. For other modes, it can be configured to be triggered

at a particular hardware condition or timer or counter condition.

It is easy to avoid the division in ADC by using the internal 2.56 V. By using this value

we can calculate that

ADC = Vin * 400. So Vin = ADC / 400.

To further illustrate the example, the voltage from a temperature sensor LM35 is sensed

with the ADC. The LM35 gives a voltage of 10mV per degree celsius. So the voltage

output = 0.01 V * temperature.

So if we measure the value of the ADC, we know that Vin = ADC/400, and again Vin =

0.01 * Temp

So 0.01 * Temp = ADC/400, or Temp = ADC / 400 / 0.01 = ADC / 4

So the temperature is just the measured value of the ADC divided by 4. Since division by

4 can be accomplished by a right shift of 2 binary digits, it can be done quite

computationally efficiently.

This is the model of LM35 IC in proteus. The Temperature is set in the model with the up

and down arrows.

Program

#include

#include


50/56

50

#include

/* Code for single pin addressing */

typedef struct

{

unsigned char bit0:1;








}io_reg;

#define D0 ((volatile io_reg*)_SFR_MEM_ADDR(PORTA))-

>bit4

#define D1 ((volatile io_reg*)_SFR_MEM_ADDR(PORTA))-

>bit5

/* Code for 7 seg display */

static unsigned char SEVEN_SEG[] = {

0x3F,

0x06,

0x5B,


51/56

51

0x4F,

0x66,

0x6D,

0x7D,

0x07,

0x7F,

0x6F,

0x77,

0x7C,

0x39,

0x5E,

0x79,

0x71};

volatile int temperature;

volatile char garbage;

ISR(ADC_vect) {

temperature = ADCL>>2; /*collect sample from ADC */

garbage = ADCL;

garbage= ADCH;

}


52/56

52

int main (void) {

int delay = 1000;

int i=0;

DDRB = 0xFF;

DDRA |= 0b11110000;

DDRD &= 0x00;

DDRC = 0xFF;

PORTC = 0x00;

//DDRD = 0x00;

/* adc initialization */

ADCSRA |= (1


53/56

53

// Enable ADC Interrupt

ADCSRA |= (1


54/56

54

D0 = 0;

D1 = 0;

PORTB = SEVEN_SEG[temperature%10];

D0 = 1;

D1 = 0;

while(--i > 0);

}

}


55/56

55

Chapter 4REFERANCES


56/56

WEBSITES

1. www.avrtutorials.com

2. www.engineersgarage.com

3. www.avrbeginners.net

4. www.alldatasheet.com

5. www.books.google.com

6. www.ebooks.com

7. www.wikipedia.org

BOOKS

MUHAMMAD ALI MAZIDI

DHANANJAY V GADREY
http://www.avrtutorials.com/http://www.avrtutorials.com/http://www.engineersgarage.com/http://www.engineersgarage.com/http://www.avrbeginners.net/http://www.avrbeginners.net/http://www.alldatasheet.com/http://www.alldatashee

avr training report

Documents