Line Following Robot

GOKARAJU RANGARAJU INSTITUTE OFENGINEERING AND TECHNOLOGY (G.R.I.E.T)

LINE FOLLOWING ROBOT

MINIPROJECT DOCUMENTATION

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TABLE OF CONTENTS

1. PROJECT INTRODUCTION

1.1 Introduction/Application areas

1.2 Required Components and Equipments.

2. DESIGN

2.1 Block Diagram and Description

2.2 Schematic

2.3 Board File

3. PROGRAMMING

3.1 Explanation of special pur pose registers

3.2 Code

4. TOOLS USED

4.1 AVR studio/Win AVR/AVRGCC

4.2 C Code

5. CONCLUSION

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1. PROJECT INTRODUCTION

1.1 INTRODUCTION

What is a line follower?Line follower is a machine that can follow a path. The path can be visiblelike a black line on a white surface (or vice-versa) or it can be invisib le likea magnetic field.

Why build a line follower?Sensing a line and maneuvering the robot to stay on course, while constantlycorrecting wrong moves using feedback mechanism forms a simple yeteffective closed loop system. As a programmer you get an opportunity to‘teach’ the robot how to follow the line thus giving it a human-like propertyof responding to stimuli.

APPLICATION AREAS:

Practical applications of a line follower :1.Automated cars running o n roads with embedded magnets2.Guidance system for industrial robots moving on shop floor

PREREQUISITES:

Knowledge o f basic digital and analog electronics.(A course on Digital Design and Electro nic Devices & Circuits would behelpful)C ProgrammingSheer interest, an inno vative brain and perseverance!

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1.2 REQUIRED COMPONENTS AND EQUIPMENTS

The functional requirements o f t he project are:

Microcontroller Atmega 85 15

Roboco n Kit.

IR Sensors

RS-232 Cable.

Win AVR and AVR Studio software.

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2. DESIGN

2.1 BLOCK DIAGRAM

SAMPLE TRACK

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DESCRIPTION

INPUT SYSTEM:

Sensor Circuit:

General Description:

The TSOP-OBSD–Single is a general purpose proximit y sensor.Here we use it for following a line. The module consist of a IRemitter and TSOP receiver pair. The high precision TSO receiveralways detects a signal of fixed freq uency. Due to this, errors due tofalse detectio n of ambient light are significantly reduced.The mod ule consists of 555 IC, working in astable multivibratorconfiguration. The output of TSOP is high whenever it receives a

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fixed frequency and low otherwise. The on-board LED indicatorhelps user to check status of the sensor without using any additionalhardware.The power consu mption of this module is low. It gives a digitaloutput and false detectio n due ambient light is low.

Functional Block Diagram /Schematic Diagram:

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Overview of Schematic:

The 555 is used as a astable multivibrator. The frequency of the 555 is tunedusing the potentiometer. The outputof 555 is given to the IR transmitter.TSOP detects a freq uency o f 38 KHz. The output of TSOP goes low when itreceives this frequency. Hence t he output pin is normally high because,

though the IR LED is co ntinuouslytransmitting, due to no white line,nothing is reflected back to the TSOP. The indication LED is off.When anwhite line is encountered, the output o f TSOP goes low, as the requiredfrequency is reflected fro m the white line. This o utput is connected to thecathode of the LED, which then t urns ON.

INFRA-RED SENSOR

Introduction

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An LED is usually a small area source, often with extra optics added

to the chip that shapes its radiation pattern. LED's are often used as small

indicator lights on electro nic devices and increasingly in higher power

applicatio ns such as flashlights and area lighting. The color of t he emitted

light depends o n the composition and condition of t he semiconducting

material used, and can be infrared (IR LED), visible, or near-ultraviolet. An

LED can be used as a regular household light source.

Use of 555 Timer:

The 555 timer is used as an astable multivibrator t hat generates a

pulse o utput with time period ‘T’.

Frequency, f = 1/(.693 x C1 x (R1 + 2 x R2))

Example:

R1 = 10K

R2 = 10k

C1 = 100uF

F = ~ 0.48 Hz

T= ~ 2 sec

This generates an outp ut pulse with a time period 2sec.

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555IC as an AstableMultivibrator

TSOP Module

Pin Diagram of a TSOP Module

Description

The TSOP17.. – series are miniaturized receivers for infrared remote

control systems. PIN diode and preamplifier are assembled on lead frame,

the epoxy package is designed as IR filter. The demodulated output signal

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can directly be decoded by a microprocessor. TSOP17..is the standard IR

remote contro l receiver series, supporting all major transmission codes.

Block Diagram

Block Diagram of TSOP Module

Circuit Diagram of IR Sensor

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Working of IR Sensor

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PROCESSING SYSTEM:

Micro Controller:

Micro-contro ller kit is constructed with ATMEGA 8515 Micro -

controller chip. The ATMEGA 8515 is a low power, high performance

CMOS 8-bit microco ntroller with 8 K bytes of flash memory. Its high density

non-volatile memory compatible with standard AVR instruction set makes

it a powerful controller that pro vides highly flexible and cost effective

solutio n to contro l app licatio ns.Micro -cont roller wo rks according to the

program written in it. Micro-contro llers are “embedded” inside some other

device so that they can control the features or actions of the prod uct.

Anot her name for a micro -controller therefore is “embedded controller”.

Micro-co ntrollers are dedicated to o ne task and run one specific pro gram.

Pin config uration of Atmega8515

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Features

• High-performance, Low-p ower AVR® 8-bit Microcontroller

• RISC Architecture– 130 Powerful Instructions – Most Single Clock Cycle Execution– 32 x 8 General Purp ose Working Registers

– Fully Static Operation– Up to 16 MIPS Throughput at 16 MHz– On-chip 2-cycle Multiplier

• Nonvolatile Program and Data Memories– 8K Bytes of In-System Self-programmable FlashEndurance: 10,000 Write/Erase Cycles– Optional Boot Code Section with Independent Lock bitsIn-System Programming by On-chip Boot ProgramTrue Read-While-Write Operation– 512 Bytes EEPROMEndurance: 100,000 Write/Erase Cycles– 512 Bytes Internal SRAM– Up to 64K Bytes Optional External Memory Space– Pro gramming Lock for Software Security

• Peripheral Features– One 8-bit Timer/Counter with Separate Prescaler and Compare Mode– One 16-bit Timer/Counter with Separate Prescaler, Compare Mode, andCapture mode– Three PWM Channels– Pro grammable Serial USART– Master/Slave SPI Serial Interface– Pro grammable Watchdog Timer with Separate On-chip Oscillator– On-chip Analo g Comparator

• Special Microcontro ller Features– Power-on Reset and Pro grammable Brown-out Detection– Internal Calibrated RC Oscillator– External and Internal Interrup t Sources– Three Sleep Modes: Idle, Power-down and Standby• I/O and Packages

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– 35 Programmable I/O Lines– 40-pin PDIP, 44-lead TQFP, 44-lead PLCC, and 44-pad QFN/MLF

• Operating Voltages– 4.5 - 5.5V for ATmega8515

• Speed Grades– 0 - 16 MHz for ATmega8515

MOTOR OUTPUT SYSTEM :

Introduction

Motor Drivers are the ICs used to drive motors when interfaced with

Microcontrollers. These ICs give a higher voltage output ranging from 4.5V

to 36V for logic 1 input. The mo tor driver ICs generally used L293D,

ULN2003 series, etc.

These ICs are used to drive bot h DC mo tors and stepp er motors.

L293D IC

The L293 and L293D are quadrup le high -current half-H drivers. The

L293 is designed to pro vide bidirectio nal drive currents of up to 1 A at

voltages from 4.5 V to 36 V. The L293D is designed to provide bidirectional

drive currents of up to 600-mA at vo ltages from 4.5 V to 36 V. Bot h devices

are designed to drive inductive loads such as relays, solenoids, dc and

bipolar stepping motors, as well as other high -current/high-vo ltage loads in

positive-supply applications.

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All inp uts are TTL compatible. Each output is a complete totem-po le

drive circuit, with a Darlington transistor sink and a pseudo-Darlingto n

source. Drivers are enabled in pairs, with drivers 1 and 2 enabled b y 1,2EN

and drivers 3 and 4 enabled by 3,4EN. When an enable input is high, the

associated drivers are enabled and their outputs are active and in phase with

their inputs. When the enable input is lo w, those drivers are disabled and

their outputs are off and in the high-impedance state. With the proper data

inputs, each pair of drivers forms a full-H (or brid ge) reversible d rive

suitable for solenoid o r moto r applications. On the L293, external high -

speed output clamp diodes should be used for inductive transient

suppression. A VCC1 terminal, separate from VCC2, is provided fo r the

logic inputs to minimize device power dissipation. The L293 and L293D are

characterized for operation from 0°C to 70°C.

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Pin Diagram

Block Diagram

Block Diagram of a Motor Controller

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Circuit Diagram

Circuit Diagram for Motor Controller (L293D

NOTE

Here the inp ut pins 2, 7 and their respective output p ins 3, 6 are enabled by

enabling EN1 i.e. giving vcc to pin 1

Similarly, t he input pins 10, 5 and their respective p ins 11, 4 are enabled by

enabling EN2 i.e. giving vcc to p in 9.

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SERIAL COMMUNICATION:

RS-232 is simp le, universal, well understoo d and supported but it

has some serious shortcomings as a data interface. The standards to 256kbps

or less and line lengths of 15M (50 ft) or less but today we see high speed

ports o n our ho me PC running very high speeds and with high q uality cable

maxim distance has increased greatly. The rule of thumb for the length a

data cable depends on speed o f the data, quality of the cable

This is a standard 9 pin cable layout for async data ona PC AT serial cable

b

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USART:

The Universal Synchronous and Asynchronous serial Receiver and

Transmitter

(USART) is a highly flexib le serial communication device.

The main features are:

•Full Duplex Operation (Independent Serial Receive and Transmit

Registers).

• Asynchronous or Synchronous Operation.

• Master or Slave Clocked Synchro nous Operatio n.

• High Resolution Baud Rate Generator.

• Suppo rts Serial Frames with 5, 6, 7, 8, or 9 Data Bits and 1 or 2 Stop Bits.

• Odd or Even Parity Generation and Parit y Check Supported by Hardware.

• Data Overrun Detection.

• Framing Error Detection.

• Noise Filtering Includes False Start Bit Detection and Digital Low Pass

Filter.

• Three Separate Interrupts on TX Complete, TX Data Register Empty, and

RX

Complete.

• Multi-p rocessor Communication Mode.

• Double Speed Asynchro no us Communication Mode.

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AVR USART vs. AVR UART –Compatibility:

The USART is fully compatible with t he AVR UART regarding:

• Bit locatio ns inside all USART Registers

• Baud Rate Generation

• Transmitter Operatio n

• Transmit Buffer Functio nalit y

• Receiver Operation

However, the receive buffering has two impro vements that will affect

the compatibility in some special cases like

•A second Buffer Register has been added. The two Buffer Registers

operate as acircular FIFO b uffer. Therefore the UDR must o nly be read once

for eachincoming data. More important is the fact that the Error Flags (FE

and DOR) and the ninth data bit (RXB8 ) are buffered wit h t he data in the

receive b uffer. Therefore the status b its must always be read before the UDR

Register is read. Otherwise the erro r status will be lost since the buffer state

is lost.

•The Receiver Shift Register can now act as a third b uffer level. This is done

byallowing the received data to remain in t he serial Shift Register (see

Figure 64) if the Buffer Registers are full, until a new start bit is detected.

The USART is therefore more resistant to Data Overrun (DOR) error

cond itions.

The following control bits have changed name, but have same functionality

and register location:

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• CHR9 is changed to UCSZ2

• OR is changed to DOR

Internal Clock Generation – The Ba ud Rate Generator:

Internal clock generation is used fo r the asynchronous and the

synchronous master modes o f operation. The USART Baud Rate Register

(UBRR) and the down-co unter connected to it function as a programmable

presale or baud rate generator. The down-counter, running at system clock

(FOSC), is loaded with the UBRR value each time the counter has counted

down to zero o r when the UBRRL Register is written. A clock is generated

each time the counter reaches zero. This clock is the baud rate generator

clock output (= FOSC/(UBRR+1)) . The Transmitter divides the baud rate

generator clock output b y 2, 8, or 16 depend ing on mode. The baud rate

generator output is used direct ly by the Receiver’s clock and data recovery

units. However, the recovery units use a state machine t hat uses 2, 8, or 16

states depending o n mode set by the state of the UMSEL , U2X , and

DDR_XCK bits.

Table: 2.5.2 Calculation of baud rate and UBRR value as per Operating modes

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Note: 1. The baud rate is defined to be the transfer rate in bit per second

(bps).

BAUD Baud rate (in bits per second, bps)

fOSC System Oscillator clock frequency

UBRR Co ntents of the UBRRH and UBRRL Registers, (0 -4095)

POWER SUPPLY UNIT:

The req uired dc power supply for the proper operat io n o f

microcontroller and its circuitry is derived from the power supply module.

This power supply unit consists of a adapter fo r the step -down o f voltage to

12V from 230 vo lts. Rectifier circuit is used for converting this 12 V AC

into 12 V DC. Regulator circuit is used fro regulating the obtained DC. Input

to this b lock is fed fro m one phase 230V AC 50 Hz mains line.

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BOARD DIAGRAM:

Block Diagram of 8515 Microcontroller Board

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2.2 SCHEMATIC:

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2.3 BOARD:

Board Diagram of the designed 8515 Microcontroller board

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3. SOFTWARE DETAILS

3.1 EXPLANATION OF SPECIAL PURPOSE REGISTERS :

USART Control a nd Status Register A - UCSRA

Bit 7 RXC : receive comp lete ; bit is set when unread data is in receiverbufferBit 5 UDRE: UART Data Register Empty

USART Control a nd Status Register A – UCSRB

Bit 4 RXEN : Receiver Enable bit

Bit 3 TXEN : Transmitter Enable bit

USART Control a nd Status Register A – UCSRC

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The UCSRC Register shares the same I/O locatio n as the UBRRH Register.

3.2 AT90S8515(AVR) Instruction set:

The Assembler accepts mnemonic

instruct ions fro m the instruction set Asummary of the instruction set mnemonicsand their parameters is given here. For adetailed description of the instruction set,refer to the AVR Data Book.

Arithmetic and Logic Instructions

Mnemonic Operands Description Operation Flags Cycles

ADD Rd,Rr Add without Carry Rd = Rd + Rr Z,C,N,V,H,S 1

ADC Rd,Rr Add with Carry Rd = Rd + Rr + C Z,C,N,V,H,S 1

Rd+1:Rd,KADIW Rd, K Add Immediate To Word Z,C,N,V,S 2

SUB Rd,Rr Subtract without Carry Rd = Rd - Rr Z,C,N,V,H,S 1

SUBI Rd,K8 Subtract Immediate Rd = Rd - K8 Z,C,N,V,H,S 1

SBC Rd,Rr Subtract with Carry Rd = Rd - Rr - C Z,C,N,V,H,S 1

SBCI Rd,K8 Subtract with Carry Immedtiate Rd = Rd - K8 - C Z,C,N,V,H,S 1

AND Rd,Rr Logical AND Rd = Rd · Rr Z,N,V,S 1

ANDI Rd,K8 Logical AND with Immediate Rd = Rd · K8 Z,N,V,S 1

OR Rd,Rr Logical OR Rd = Rd V Rr Z,N,V,S 1

ORI Rd,K8 Logical OR with Immediate Rd = Rd V K8 Z,N,V,S 1

EOR Rd,Rr Logical Exclusive OR Rd = Rd EOR Rr Z,N,V,S 1

COM Rd One's Complement Rd = $FF - Rd Z,C,N,V,S 1

NEG Rd Two's Complement Rd = $00 - Rd Z,C,N,V,H,S 1

SBR Rd,K8 Set Bit(s) in Register Rd = Rd V K8 Z,C,N,V,S 1

CBR Rd,K8 Clear Bit(s) in Register Rd = Rd · ($FF - K8) Z,C,N,V,S 1

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INC Rd Increment Register Rd = Rd + 1 Z,N,V,S 1

DEC Rd Decrement Register Rd = Rd -1 Z,N,V,S 1

TST Rd Test for Zero or Negative Rd = Rd · Rd Z,C,N,V,S 1

CLR Rd Clear Register Rd = 0 Z,C,N,V,S 1

SER Rd Set Register Rd = $FF None 1

SBIW Rdl,K6 Subtract Immediate from Word Rdh:Rdl = Rdh:Rdl - K 6 Z,C,N,V,S 2

Branch Instructions:

Mnemonic Operands Description Operation Flags Cycles

RJMP k Relative Jump PC = PC + k +1 None 2

IJMP None Indirect Jump to (Z) PC = Z None 2

STACK = PC+1, PC = PC +RCALL k Relative Call Subroutine None 3/4*

k + 1

ICALL None Indirect Call to (Z) STACK = PC+1, PC = Z None 3/4*

RET None Subroutine Return PC = STACK None 4/5*

RETI None Interrupt Return PC = STACK I 4/5*

CPSE Rd,Rr Compare, Skip if equal if (Rd ==Rr) PC = PC 2 or 3 None 1/2/3

CP Rd,Rr Compare Rd -Rr Z,C,N,V,H,S 1

CPC Rd,Rr Compare with Carry Rd - Rr - C Z,C,N,V,H,S 1

CPI Rd,K8 Compare with Immediate Rd - K Z,C,N,V,H,S 1

if(Rr(b)==0) PC = PC + 2 orSBRC Rr,b Skip if bit in register cleared None 1/2/33

if(Rr(b)==1) PC = PC + 2 orSBRS Rr,b Skip if bit in register set None 1/2/3

3

Skip if bit in I/O register if(I/O(P,b)==0) PC = PC + 2SBIC P,b None 1/2/3cleared or 3

if(I/O(P,b)==1) PC = PC + 2SBIS P,b Skip if bit in I/O register set None 1/2/3

or 3

if(SREG(s)==0) PC = PC +BRBC s,k Branch if Status flag cleared None ½k + 1

if(SREG(s)==1) PC = PC +BRBS s,k Branch if Status flag set None ½

k + 1

BREQ k Branch if equal if(Z==1) PC = PC + k + 1 None ½

BRNE k Branch if not equal if(Z==0) PC = PC + k + 1 None ½

BRCS k Branch if carry set if(C==1) PC = PC + k + 1 None ½

BRCC k Branch if carry cleared if(C==0) PC = PC + k + 1 None ½

BRSH k Branch if same or higher if(C==0) PC = PC + k + 1 None ½

BRLO k Branch if lower if(C==1) PC = PC + k + 1 None ½

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BRMI k Branch if minus if(N==1) PC = PC + k + 1 None ½

BRPL k Branch if plus if(N==0) PC = PC + k + 1 None ½

Branch if greater than or equalBRGE k if(S==0) PC = PC + k + 1 None ½

(signed)

BRLT k Branch if less than (signed) if(S==1) PC = PC + k + 1 None ½

BRHS k Branch if half carry flag set if(H==1) PC = PC + k + 1 None ½

Branch if half carry flagBRHC k if(H==0) PC = PC + k + 1 None 1/2cleared

BRTS k Branch if T flag set if(T==1) PC = PC + k + 1 None ½

BRTC k Branch if T flag cleared if(T==0) PC = PC + k + 1 None ½

BRVS k Branch if overflow flag set if(V==1) PC = PC + k + 1 None ½

Branch if overflow flagBRVC k if(V==0) PC = PC + k + 1 None ½

cleared

BRIE k Branch if interrupt enabled if(I==1) PC = PC + k + 1 None ½

BRID k Branch if interrupt disabled if(I==0) PC = PC + k + 1 None ½

Data Transfer Instructions:

Mnemonic Operands Description Operation Flags Cycles

MOV Rd,Rr Copy register Rd = Rr None 1

LDI Rd,K8 Load Immediate Rd = K None 1

LDS Rd,k Load Direct Rd = (k) None 2*

LD Rd,X Load Indirect Rd = (X) None 2*

LD Rd,X+ Load Indirect and Post-Increment Rd = (X), X=X+1 None 2*

LD Rd,-X Load Indirect and Pre-Decrement X=X-1, Rd = (X) None 2*

LD Rd,Y Load Indirect Rd = (Y) None 2*

LD Rd,Y+ Load Indirect and Post-Increment Rd = (Y), Y=Y+1 None 2*

LD Rd,-Y Load Indirect and Pre-Decrement Y=Y-1, Rd = (Y) None 2*

LDD Rd,Y+q Load Indirect with displacement Rd = (Y+q) None 2*

LD Rd,Z Load Indirect Rd = (Z) None 2*

LD Rd,Z+ Load Indirect and Post-Increment Rd = (Z), Z=Z+1 None 2*

LD Rd,-Z Load Indirect and Pre-Decrement Z=Z-1, Rd = (Z) None 2*

LDD Rd,Z+q Load Indirect with displacement Rd = (Z+q) None 2*

STS k,Rr Store Direct (k) = Rr None 2*

ST X,Rr Store Indirect (X) = Rr None 2*

ST X+,Rr Store Indirect and Post-Increment (X) = Rr, X=X+1 None 2*

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ST -X,Rr Store Indirect and Pre-Decrement X=X-1, (X)=Rr None 2*

ST Y,Rr Store Indirect (Y) = Rr None 2*

ST Y+,Rr Store Indirect and Post-Increment (Y) = Rr, Y=Y+1 None 2

ST -Y,Rr Store Indirect and Pre-Decrement Y=Y-1, (Y) = Rr None 2

ST Y+q,Rr Store Indirect with displacement (Y+q) = Rr None 2

ST Z,Rr Store Indirect (Z) = Rr None 2

ST Z+,Rr Store Indirect and Post-Increment (Z) = Rr, Z=Z+1 None 2

ST -Z,Rr Store Indirect and Pre-Decrement Z=Z-1, (Z) = Rr None 2

ST Z+q,Rr Store Indirect with displacement (Z+q) = Rr None 2

LPM None Load Program Memory R0 = (Z) None 3

IN Rd,P In Port Rd = P None 1

OUT P,Rr Out Port P = Rr None 1

PUSH Rr Push register on Stack STACK = Rr None 2

POP Rd Pop register from Stack Rd = STACK None 2

Bit and Bit-test Instructions:

Mnemonic Operands Description Operation Flags Cycles

LSL Rd Logical shift left Rd(n+1)=Rd(n), Rd(0)=0, C=Rd(7) Z,C,N,V,H,S 1

LSR Rd Logical shift right Rd(n)=Rd(n+1), Rd(7)=0, C=Rd(0) Z,C,N,V,S 1

Rotate left through Rd(0)=C, Rd(n+1)=Rd(n),ROL Rd Z,C,N,V,H,S 1carry C=Rd(7)

Rotate right through Rd(7)=C, Rd(n)=Rd(n+1),ROR Rd Z,C,N,V,S 1

carry C=Rd(0)

ASR Rd Arithmetic shift right Rd(n)=Rd(n+1), n=0,...,6 Z,C,N,V,S 1

Rd(3..0) = Rd(7..4), Rd(7..4) =SWAP Rd Swap nibbles None 1Rd(3..0)

BSET s Set flag SREG(s) = 1 SREG(s) 1

BCLR s Clear flag SREG(s) = 0 SREG(s) 1

SBI P,b Set bit in I/O register I/O(P,b) = 1 None 2

CBI P,b Clear bit in I/O register I/O(P,b) = 0 None 2

Bit store from registerBST Rr,b T = Rr(b) T 1

to T

Bit load from register toBLD Rd,b Rd(b) = T None 1T

SEC None Set carry flag C =1 C 1

CLC None Clear carry flag C = 0 C 1

SEN None Set negative flag N = 1 N 1

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CLN None Clear negative flag N = 0 N 1

SEZ None Set zero flag Z = 1 Z 1

CLZ None Clear zero flag Z = 0 Z 1

SEI None Set interrupt flag I = 1 I 1

CLI None Clear interrupt flag I = 0 I 1

SES None Set signed flag S = 1 S 1

CLN None Clear signed flag S = 0 S 1

SEV None Set overflow flag V = 1 V 1

CLV None Clear overflow flag V = 0 V 1

SET None Set T-flag T = 1 T 1

CLT None Clear T-flag T = 0 T 1

SEH None Set half carry flag H = 1 H 1

CLH None Clear half carry flag H = 0 H 1

NOP None No operation None None 1

SLEEP None Sleep See instruction manual None 1

WDR None Watchdog Reset See instruction manual None 1

The Assembler is not case sensitive.

The operands have the following forms:

Rd: Destination (and source) register in the register file.

Rr: Source register in the register file.

b:Constant (0-7), can be a constant expression.

s:Constant (0-7), can be a constant expression.

P:Constant (0-31/63 ), can be a constant expressio n.

K6: Constant (0 -63), can be a constant expression.

K8: Constant (0 -255), can be a constant expression.

k:Constant, value range depending on instructio n .Can be a constant

exp ression.

q: Constant (0-63), can be a constant expression.

Rdl: R24, R26, R28, R30. For ADIW and SBIW instructions.

X,Y,Z: Indirect address registers (X=R27 :R26, Y=R29:R28, Z=R31:R30).

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4.TOOLS USED:

4.1 AVR studio/Win AVR/AVRGCC

Introduction to AVR

AVR studio is an Integrated Develop ment Enviro nment (IDE) fo r

writing and deb ugging AVR applications. Currently as a code writing

environment, it sup ports the included AVR Assembler and any external

AVR GCC compiler in a complete IDE environment. AVR Studio supports

the complete range of ATMEL AVR too ls and each release will always

contain the latest updates for both the tools and supp ort o f new AVR

devices. AVR Studio 4 has a modular architecture which allows even more

interaction wit h 3rd party software vendors.

ATMEL , the company that makes the AVR microcontrollers also

provides a utility called AVR Studio which will help you to d o all these

tasks.

Using AVR Studio as an IDE gives you 2 main advantages:

1. Edit and debug in the same application windows. Faster error

track ing.

2. Breakpoints are saved and restored between sessio ns, even if

code are edited

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Save and Open Projects

All projects are saved with yo ur selected name with the ending APS .

When the user wants to reopen a pro ject, this can be done under the file

menu and the recent ly used file list, or under the project menu, open project.

Project output view

After build ing, assembling o r compiling the project, the build output

window prompts with messages. If any errors occur, the user can double-

click on the message, and the marker will show correct position in the source

window.

Startup wizard

The startup wizard is displayed every t ime yo u start AVR Studio 4.

Fro m within this dialog you can quickly reopen the latest used projects,

change debug platform/device setup or create a new pro ject. Just double-

click on the wanted project and it will automatically open and restore to its

last settings.

New project

Doub le-click on the AVR Studio icon on your Desktop

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The following screen opens up:

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Click on New Project tab in the pop-up windo w and the following screen

opens up.

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Click on AVR GCC inProject .

The following screen opens up. Type in the name of your project –

myleds. Check the boxes ‘Create file’ and ‘Create Folder’. Creating

separate folders for d ifferent pro jects will help you maintain them properly.

Since the folder does not exist, AVR Studio will pro mpt you saying, the

folder does not exist and it will create a new folder. Say ‘yes’ to this prompt.

Click on Finish .

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Device selection

We have to select which device we are going to use , in this project

we use AVR Simulator as debug platform and AT mega 8515 as device.

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AVR Stud io creates a folder called myleds in the path specified by

you and a project named myleds.aps and a source file named myleds.c

Key in t he blinking.c program. Click o n the File Save icon. Now you

have written Ccode, you need to compile the p rogram. For this, you need to

select the microcontroller and the sp eed at which it works. The

microcontroller we are using is ATmega8515 and the speed at which it is

working is 8MHz .These two parameters are set as follows in the Project

Options in Device and Frequency optio ns.

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The Project Options screen opens up by clicking on the Edit Current

ConfigurationOptions ico n.

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Now, that we have set the Project Options, we will comp ile it. This can be

done by clicking on the Build Active Configuration icon.

Or yo u can go t he Build option under the Build tab.

When the Build is successful, you are intimated that the Build has gone

through with 0 warnings. This display will be in the Build Window.

42

If there are errors, you will need to correct those and do a Build again. The

Build will create many files, but the one we are interested in will be the

.hex file. This is a file whichcan be downloaded to the GRIET trainer kit and

executed

Generally the program for the required application is written in edit plus and

stored with ‘.c’ extension. The WINAVR cd provides some example

programs. Fro m that copy any one o f the bat file (generally they are with

.bat extension).

Let the program written by us be name.c .Now copy any one of bat file

provided in WINAVR cd and replace its name by name.bat. Now editing has

to be done by rep lacing led by name and now the batch file looks like

AVR-gcc-g-oc-mmcu=atmega85 15 -c-name.c

AVR-gcc-g--mmcu=atmega8515-c-o name.out,name.o

AVR-objcopy-j.text-O ihex name.outname.hex

The batch file created can be run by doub le clicking it and thereb y we find

3 files name.hex,name.out,name.o. Now o pen the AVRstudio software and

click o n the tools b utton as shown in the figure above (only after connecting

the b oard to the cpu). The AVRPROG soft ware comes with one o f the tools

supplied with AVRstud io.

If the board is

not connected

properly we wil

receive a

message as

follows:

43

This message ind icates

that the board is not

detected. Check once

again the connector and

reset the IC properly (the

IC can be reset by

click ing simultaneously

SW1 switch and power

slid ing switch). Next

click the AVRPROG

executable file, now we

can see the window as

shows:

Click on the Browse

button and select the hex

file name.hex. Click the

program button to load the program onto the target device box shows the

target controller to which the AVRPROG selected to advanced optio ns can

be viewed but the user is not allowed to change the settings, which damage

the Boot loader.

Now the pro gram is loaded in to the target.

To run the program in the contro ller, power off the controller and switch it

on after some seconds (say 2 seconds) and hence after the microcontroller

works on t he required app lication present in name.c.

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Program to toggle the LEDs

/* Program to toggle the LEDs

The two LEDs are connected to portd pins pd6 and pd7

The LED1 is switched on first and after sometime LED2 is switched on */

#include<avr/io.h>

void main()

{

inti,j;

DDRD=0xff; //to make port d o utput for LEDs

PORTD=0xff; //making all LEDs Off

while(1)

{

PORTD=0x7f; //LED1 is switched on and LED2 o ff

for(i=0;i<500;i++)

for(j=0;j<2500;j++); //delay

PORTD=0xbf; //LED1 is o ff and LED2 is on

for(i=0;i<500;i++)

for(j=0;j<2500;j++);

}

}

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Program for Buzzer

/* pro gram to so und the b uzzer

buzzer is connected to p in pd4 of po rtd*/

#include<avr/io.h>

void main()

{

unsigned char status;

inti,j;

DDRD=0xff; //making as output for buzzer

PORTD=0Xff; //internal pull ups

while(1)

{

PORTD=0xef; //buzzer switched off

for(i=0;i<200;i++)

for(j=0;j<200;j++);// delay

PORTD=0xff; //buzzer on

for(i=0;i<200;i++)

for(j=0;j<200;j++);

}

}

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Program for Motor

/* pro gram for driving the motor in forward and reverse directions

motor1 are connected to portb p ins 0 and 1

differential input to the pins causes the motor to rotate*/

#include<avr/io.h>

void main()

{

inti,j;

DDRB=0xff; //for driving the motors making the portb as outp ut.

PORTB=0xff; //internal pull ups

while(1)

{

PORTB=0 xaa; //mak ing motor turn in forward directio n

for (i=0; i<10000;i++)

for(j=0;j<10000;j++); //delay

PORTB=0 x55; //making motor turn in reverse direction

for (i=0; i<10000;i++)

for(j=0;j<10000;j++);

}

}

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Program for Sensors

Program for IR Sensor

/* IR sensor interfacing with LEDs

IR sensor ret urns logic 0 when obstacle is detected

Program t o switch on the LEDs if anything is detected by the IR senso r

sensors are connected to port a and leds are connected to portd pins pd6

adn pd7 */

#include<avr/io.h>

void main()

{

unsigned char status;

DDRA=0x00; // making port a inp ut for taking sensor status

DDRD=0xff; //making portd output to switch o n the leds

PORTD=0xff; //making all leds off

PORTA=0xff; //for internal pullups

while(1)

{

status=PINA;

PORTD=0xff; //making LEDs off

if((status&(0x07))==0x00)

PORTD=0x3f; //making LEDs on

}

}

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Programs to interface sensor and motors

/* pro gram to interface sensors and to drive motors depending on sensor

status

Port a is used to interface sensors and port b to drive the motors */

#include<avr/io.h>

#include<avr/delay.h>

void delay();

void main()

{

DDRB=0xff;

DDRA=0x00;

DDRD=0xff; //making portd as output to glow LEDs and

buzzer

PORTA=0xff;

PORTB=0xaa;

delay();

while(1)

{

if((PINA&0x01)==0x00)

{

PORTD=0x3f;//leds and buzzer on

PORTB=0 x11;//left

delay();

PORTB=0xaa;//forward

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delay();

PORTB=0 x22;//right

delay();

PORTB=0 xaa;//forward

delay();

PORTD=0xef;//leds and b uzzer off

}

else PORTB = 0xaa;

}

}

void delay()

{

int i,j;

for(i=0;i<6000;i++)

for(j=0;j<6000;j++);

}

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4.2 C CODE:

/* LINE FOLLOWING ROBOT

PortA : 0 0 0 0 0 0 s2 s1

PortB : R R L L 0 0 0 0

PortC : Switch Pin2

PortD : L1 L2 0 B 0 0 0 0 */

#include<avr/io.h>

int main()

{

DDRA=0x00; //Sensor Input

DDRB=0xff; //Motor Output

DDRC=0x00; //Switches Input

DDRD=0xff; //Leds,Buzzer Output

PORTA=0xff;

PORTC=0xff;

while(1)

{

if(!(PINC&0x02))

{

51

goto x;

}

}

x: while(1)

{

while((PINA&0x03)==0x03) //STRAIGHT

{

{

PORTB=0x50;

}

}

while((PINA&0x03)==0x00) //STOP

{

{

PORTB=0x00;

}

}

if((PINA&0x03)==0x01) //RIGHT

{

PORTD=0x10; //Buzzer ON

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while((PINA&0x03)==0x01)

{

PORTB=0x40;

}

PORTD=0xC0; //Buzzer OFF

}

if((PINA&0x03)==0x02) //LEFT

{

PORTD=0x10; //Buzzer ON

while((PINA&0x03)==0x02)

{

PORTB=0x10;

}

PORTD=0xC0; //Buzzer OFF

}

}

}

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CONCLUSION:

It has been a great learning experience working o n our project - The LineFollower. In this new age where the effort o f man is min imized by usingmachines, the emergence of robo ts has helped improve many facets of life.The line follower is one of those simpleyet efficient robots which are extensively used in developed industries intransporting goods to and fro along a specific path which inturn lessens theburden of the workers and improves the working of the ind ustry.

The main aim of o ur project was todevelo p a miniature linefollower in which we have succeeded. We lookforward to develop an industry oriented line follower where it can helpincrease the efficiency of the industry.

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