8051 interfacings presentation from basics to hobby robot by embeddedmarket.com

www.EmbeddedMarket.com

Robot Controls using 8051Presented by: Pratik Deshpande

Microcontroller Kits Available at www.DeccanRobots.com

Microcontroller, Arduino & Embedded Kits available at EmbeddedMarket.com

mWorkshop Objective

Understand the real world development using Microcontrollers

Explore the features of microcontroller and use them in real life applications

Use 89V51RD2 microcontroller to control a Hobby Robot

mDetails of Workshop

Your Basic Preparation

Interface 8051 with various circuits

Use built-in features of 8051

Apply above said learning to control a hobby robot

This workshop is to learn the control techniques. Mechanical aspects will not be discussed.

mMicrocontroller & Computer

Basic Parts of a Computer

Processor

Hard disk

Monitor

Keyboard

mMicrocontroller & Digital Circuits

Microcontroller has built in

Processor

Memory to Store Program

Memory to Store Data

Ports for Input & Outputs

Flexible

Multipurpose

mWhy to use a Microcontroller?

Why use Microcontroller instead of PC?

Why use Microcontroller instead of Digital Circuits?

mProducts using Microcontroller

mEmbedded Vs IT Sector

Microcontroller is entry point to the Embedded Development

Embedded is Hardware + Software

IT is Software only

Recent Global Economic downturn has less effect on Embedded Related companies

mLet’s get prepared

You should know:

Internals of microcontrollers

Writing programs to create application

Programming languages

Bits , Bytes and Address

Binary, Decimal & Hexadecimal Numbers

Details of Interface (Input / Output circuits)

Built-in Features of Microcontroller

8051 Microcontroller

AT89S51

AT89S52

P89V51RD2

Differs in

Program memory Size

Data Memory Size

Certain built-in features

Internals of 89V51RD2

8 Bit processor

64 KB Flash (Memory to store program)

1 KB RAM (Memory to store data)

Special Function Registers (SFR – Used

for Configuration of Built-in Features)

32 I/O Lines

Writing programs to create application Assign value to a Port

Read value from a Port

Process input values

Configure, Enable & disable

Built-in Features

Programming languages For Microcontrollers Human readable programming language

• Assembly Language

• C Language

• Basic Language

Machine Code

• Hex File

Start:

JB P2.0,Start

JB P1.0,MakeItON

SETB P1.0

:1000000020A0FD209004D2908002C290

30A0FD80FC

:01001000EF00

:00000001FF

Assembler Software

Copy Hex File to Microcontroller

Programmer

Device

1 0 1 0 1 0 1 0

0th Bit7th Bit

MSB LSB

1 Byte

Binary = 10101010b

Decimal = 170d

Hexadecimal = AAh

10111001b

128 Byte RAM

LED Interfacing

Seven Segment Interfacing

Reading Input from Switch

Display text to LCD

Drive DC Motor using L293D

Drive Stepper Motor using ULN2803

Driver Relay using ULN2803

Send text to PC using RS232 Serial Communication

Transmit Infrared

Receive Infrared Signal

Counter

Serial Communication

Interrupts

Flash memory & Data memory

Program is written in Assembly Language

“Assembler software” converts it to HEX

Hex File is downloaded to Microcontroller

via “Programming Device”

Hex File is Stored in Microcontroller’s

“Flash memory”

Variables used by this program are stored

in Microcontroller’s Data memory (RAM)

mTime to See a Demo

Running LEDs

Seven Segment Display showing Numbers 0 to 9

mAre you prepared now?

By now you know

Difference between microcontroller, PC and digital

circuit

Internals of microcontrollers

Writing programs to create application

Programming languages

Binary, Decimal & Hexadecimal Numbers

You have seen one demo

Are you prepared to learn “How to write a program in Assembly Language?”

mAssembly Language

We will learn (Limited Scope to fit available time)

Assigning Byte values

Assigning Bit values

Logical Operations on Bytes

Logical Operations on Bits

Rotate Values

Increment & Decrement Values

Direct Jumps

Conditional Jumps For Bytes

Conditional Jumps For Bits

mAssembly Language

Assigning & Copy Byte values

MOV R0, #55h

MOV A, R0

MOV A, #55h

MOV 90h, A

MOV 90h, #33h

mAssembly Language

Assigning Bit values

SETB 00h

CLR 00h

CPL 00h

Copy Bit values

MOV C, 00h

MOV 00h, C

mAssembly Language

Logical operations on Byte

ANL A, R0

ANL A, 90h

ANL A, #55h

ANL 90h, A

ANL 90h, #55h

Same format applies for

mAssembly Language

Logical Operations on Bits

ANL C, 00h

ORL C, 00h

mAssembly Language

Rotate Values

1 0 1 0 1 1 0 0

mAssembly Language

Increment & Decrement values

INC R0

INC 00h

DEC R0

DEC 00h

mAssembly Language

Following types of commands will be covered during further demos

Direct Jumps

Conditional Jumps For Bytes

Conditional Jumps For Bits

mWhy 89V51RD2?

Reasons for selecting 89V51RD2

8051 compatible

No expensive programmer device required

Big Flash memory size to store large

program hex

Easily available

mFree Gift & Purchase

Register yourself to www.EmbeddedMarket.com

Facebook.com/EmbeddedMarket

mPCB Design & Manufacturing

Email your schematics and get the price estimate for PCB Design & manufacturing

Payment by DD

Delivery by courier

Delivery time 6-10 days

Single & Double Side Designs

Email ID: support@deccanrobots.com

mGet, Set, Go…

Let’s begin the real learning

Its time to write your First program

To Glow One LED

• CLR P1.0

To Glow alternate 4 LEDs ON and 4 LEDs OFF

• MOV P1, #55h

Refer next slide for LED circuit.

How to write this code?

Where to write this code?

How to convert it to HEX?

mGet, Set, Go…

LED Circuit on 89V51RD2 Starter Kit

m8051IDE & FlashMagic

89V51RD2

Check this

Select Hex File

Start After

Hardware

Setup is ready

m89V51RD2 Starter Kit

Hardware Setup to Program

Connect Serial

9-12V DC

m89V51RD2 Internals

64KB Flash memory

1KB Data RAM

Special Function Registers

4 Ports

m89V51RD2 Internals

Internal Memory Organization Configuration

Registers,

Port Registers,

Maths registers

Memory to

Store values of

variables.

e.g. Count is 12

Memory from 00h to 07h is

also termed as R0 to R7

m89V51RD2 Internals

List of Special Function Registers (SFR)

Math – A, B

Interrupt – IE

Timer Control – TMOD, TCON

Timer / Counter – TH0, TL0, TH1, TL1

Serial Communication – SCON, SBUF

PORT – P0, P1, P2, P3

m89V51RD2 Pin details

Crystal

mGenerate Delay using Timer

Crystal

11.0592

Crystal Frequency is 11.0592 MHz

1 Machine cycle = Crystal frequency/12

i.e. 12 clocks makes one machine cycle

Machine cycle is time required to

• Fetch instruction from Flash Memory

• Execute the instruction

Every microcontroller has different Machine cycle time

How much time is require to fill this glass?

Depends on Water Speed

& Glass size

89V51RD2 has 3 Timers built-in

They are Timer0, Timer1, Timer2

Let’s use Timer0 to Generate a delay of approximate 1 second

Timer0 is built-in feature of 89V51RD2

SFRs related to Timer0 are:

TH0, TL0 (Call it as T0)

Special Function register TH0 and TL0 is like empty glass

Combined size of TH0 and TL0 is 16 Bits

i.e. T0 is of 16 bit size

Now you know the size of empty Glass

Next Task is to calculate the Time required to fill these 16bits.

1 Machine cycle Frequency

=11.0592MHz /12

= 0.9216 MHz

T=1/ F

T (Time required for 1 machine cycle)

=1/0.9216

=1.0850694

=1.085 Micro Seconds (Round Off)

In other words we can say that with 11.0592 MHZ Crystal Connected, Timer’s value will increment every 1.085 micro seconds.

T0 is of 16 bit size, thus it can store 65536 drops of water.

T0 will take

65536 x 1.085= 71106.56 Micro Sec

Or 71.10 MiliSec to overflow

If we want to count 1 second then we have to overflow timer approximately 14 times.

Because 1 sec = 1000 mili sec

1000 / 71.1 =14.06 = 14 times approx

Now let’s configure the SFRs

Gate C/T M1 M0 Gate C/T M1 M0

7 6 5 4 3 2 1 0

Timer 1 Timer 0

TMOD register is divided into 2 identical parts.

Bit M0 and M1 are used to set Mode of timer

Bit C/T is used to specify if you want a timer or counter

Gate Bit will allow you to use timer as stopwatch, i.e. timer will run only if externally a switch is pressed.

7 6 5 4 3 2 1 0

Timer 1 Timer 0

What will be value of TMOD to generate 1 Second delay?

Gate = 0 (We don’t want a stop watch)

C/T = 0 (We want timer, not counter)

M1=0 (*)

M0=1 (*)

• * M1=0 and M0=1 configures the Timer1 as 16bit timer.

• Other settings are 13 bit timer, 8 Bit timer, Split Timer. The 16 bit timer mode is most suitable for our application.

Now we have configured the Timer0 in 16bit timer mode

We know that Timer0 must overflow 14 times to generate 1 second delay

But how to Start the Timer?

Use SFR named TCON to start timer

TR0 is used to start and stop the Timer0

Let’s see our partial code now

TF1 TR1 TF0 TR0 IE1 IT1 IE0 IT0

7 6 5 4 3 2 1 0

Used for Timer

Control

Partial Code to generate 1 Second delay

MOV TMOD,#00000001b

SETB TR0

Now how to monitor the 14 times overflow?

TF0 is set to 1 automatically as T0 Overflows after 71.1 mili sec

Thus we should count 14 such overflows by monitoring TF0.

See full code on the next page

7 6 5 4 3 2 1 0

Used for Timer

Control

Delay:

MOV R0,#14d

MOV TMOD,#00000001b

Tstart:

SETB TR0

JNB TF0,Loop

CLR TF0

CLR TR0

DJNZ R0,Tstart

Configure TMOD

Start Timer0

Wait for one Overflow

Clear Overflow

Stop Timer

Do it for 14 Times

SETB P1.0

Start:

LCALL Delay

CPL P1.0

SJMP StartDelay:

MOV R0,#14d

MOV TMOD,#00000001b

Tstart:

SETB TR0

JNB TF0,Loop

CLR TF0

CLR TR0

DJNZ R0,Tstart

mRead Switch Input

MOV P2,#00h

Start:

JB P1.0,Start

CPL P2.0

JNB P1.0,Wait

Sjmp Start

mDC Motor Control

Try connecting DC

Motor here

Let’s now control it using 89V51RD2 Microcontroller

mDC Motor Control

L293D DC Motor Driver Circuit

mDC Motor Control

Refer source Code

mSeven Segment Display

Board mapping on

the next screen.

Refer source code

mStepper Motor Driver

Demonstrated using MITSUMI Make Stepper Motor M35SP-8

Step Angle 7.5o

Thus requires 360/7.5 = 48 Steps to complete one full rotation.

Stepper motors are used for their accuracy.

Stepper motors have no Speed or RPM parameter

Most common use is in CNC machines

A B A1 B1

1 1 0 0

A B A1 B1

0 1 1 0

A B A1 B1

0 0 1 1

A B A1 B1

1 0 0 1

Refer Source code

mInterrupts

An interrupt is some event which interrupts normal program execution

Normal Program Running

Interrupt Received

Normal Program Halted

Sub-Routine Executed as expected by the Interrupt

Normal Program Continues

mInterrupts

This subroutine, called an interrupt handler, is only executed when a certain event (interrupt) occurs.

Types of interrupts

Timer 0 Overflow.

Timer 1 Overflow.

Timer 2 Overflow

Reception/Transmission of Serial Character.

External Event 0.

External Event 1.

mExternal Interrupt

This subroutine must be written at specific flash memory address.

External 0 at Program memory address 0003h

External 1 at Program memory address 0013h

Timer 0 at Program memory address 000Bh

Timer 1 at Program memory address 001Bh

Serial Tx/Rx at Program memory address 0023h

mExternal Interrupt

How to Enable Interrupt

EA: All interrupt enable

ES: Enable Serial Interrupt

ET1: Enable Timer 1 Interrupt

EX1: Enable External 1 Interrupt

ET0: Enable Timer 0 Interrupt

EX0: Enable External 0 Interrupt

EA - - ES ET1 EX1 ET0 EX0

7 6 5 4 3 2 1 0

mExternal Interrupt

Refer Source Code

mCounter

7 6 5 4 3 2 1 0

Used for Timer

Control

7 6 5 4 3 2 1 0

Timer 1 Timer 0

MOV TMOD,#00000101b

SETB TR0

mCounter

start:

MOV TMOD,#00000101b

SETB TR0

MOV P2,TL0

SJMP Loop

mRelay Interfacing

Use a Switch to

ON & Off Relay,

Observe the

“Tick” sound

generated when

Relay’s magnet

is energized

mRelay Interfacing

230V PhN

mLCD Interfacing

LCD Circuit

mLCD Interfacing

mTSOP1738 RC5 Remote

38KHZ Industrial Grade IR receiver

Refer Source Code

mRS232

Use RS232 to communicate between a PC and embedded product

Data logger is common example of it

mRS232

Rx & Tx

mRS232

Steps to Communicate

Both devices (PC & embedded product)

must decide on common speed of

communication,

This speed is called as baud rate

We will use 2400 baud rate

i.e. 2400 bits per second

mRS232

SFR’s required for Serial Comunication

Baud rate settings

mRS232

SCON register is used to specify RS232 communication settings:

SM0SM1SM2RENTB8 RB8 TI RI

7 6 5 4 3 2 1 0

Mode of

RS232I want to

receive data

over RS232

Indicates

that Data is

transmitted

Indicates

that Data is

received

mRS232

Mode of serial communicationSM0 SM1 Serial

ModeExplanation Baud Rate

0 0 0 8-bit Shift Register

Oscillator / 12

0 1 1 8-bit UART Set by Timer 1

1 0 2 9-bit UART Oscillator / 32

1 1 3 9-bit UART Set by Timer 1

mRS232

Baud rate = 2400.

Mode type = Mode 1 of serial communication.

In this mode we can send and receive 8 bit data.

Baud rate to send this data can be set using Timer 1.

mRS232

Timer 1 is used in 8-bit auto reload mode to generate required BAUD rate.

We can not use Timer 0. There no such internal provision to do so

mRS232

Lets understand Timer 1 Configurations:

TMOD = 00100000b (8-bit auto reload mode)

In 8 bit auto-reload mode, Timer 1 acts as 8 bit and not 16 bits.

8 bits of TL1 are used to increment timer value.

8 bits of TH1 are used to tell TL1 to start incrementing again from this value as it overflows. This is called as auto-reload.

mRS232

This re-load value for TH1 will be calculated using this formula:

TH1 = 256 - ((Crystal / 384) / Baud)

TH1 = 256 - ((11059000 / 384) / 2400 )TH1 = 256 - ((28,799) /2400)TH1 = 256 – 11.99 = 244.00042=

mRS232

TMOD = 00100000b (8-bit auto reload mode)

TH1= 244d (as per formula)

Remember to make 7th bit of PCON register to 0.

If it is set to 1 then speed will be doubled.

This bit is also called as SMOD.

mRS232

Refer Source Code

8051 interfacings presentation from basics to hobby robot by embeddedmarket.com

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