Micro controller-8051

22

CONTENTS:CONTENTS:

IntroductionIntroductionBlock Diagram and Block Diagram and Pin Description of the 8051Pin Description of the 8051RegistersRegistersMemory mapping in 8051 Memory mapping in 8051 Stack in the 8051Stack in the 8051I/O Port ProgrammingI/O Port ProgrammingTimerTimer

33

1. meeting the computing needs of the task efficiently and cost effectively

• speed, the amount of ROM and RAM, the number of I/O ports and timers, size, packaging, power consumption

• easy to upgrade

• cost per unit

2. availability of software development tools

• assemblers, debuggers, C compilers, emulator, simulator, technical support

3. wide availability and reliable sources of the microcontrollers.

Introduction : Three criteria in Choosing a Microcontroller:

8 bit controllers – more 8 bit controllers – more requirementsrequirements

44

Embedded System :Embedded System :

55

Fall 2004Fall 2004 Embedded Systems

Development processDevelopment processPlanning of tasks & interactions

edit

taskcode1.A51 taskcode2.c

Assembler C-compiler

misc.LIB Linker/Locator

Burn in EPROM

Download to board

Revise !

Debugging ???

8051 Microcontroller Kit Layout8051 Microcontroller Kit Layout

77

General Purpose Microprocessor General Purpose Microprocessor v/s Microcontrollerv/s Microcontroller

88

Block Diagram : 8051 Block Diagram : 8051

99

1010

Block DiagramBlock Diagram

CPU

On-chip RAM

On-chip ROM for program code

4 I/O Ports

Timer 0

Serial PortOSC

Interrupt Control

External interrupts

Timer 1

Timer/Counter

Bus Control

TxD RxDP0 P1 P2 P3

Address/Data

Counter Inputs

PC Interface Lab.

Stepper motor etc. Lab

Delay Generation Labs

1111

ROMLike Brain

OscillatorLike Heart

Data flow Like BloodFlow

Ports likeHands/Legs

InternalDataBus

Prepares the sequence of operations

8051 Block Diagram8051 Block Diagram

1212

1515

ROMLike Brain

OscillatorLike Heart

Data flow Like BloodFlow

Ports likeHands/Legs

InternalDataBus

Prepares the sequence of operations

SignalSignalPins Pins

Figure

8051 pinouts & Functions

8051 Block Diagram

Fetch CycleFetch Cycle

1818

8051 Family State Sequence8051 Family State Sequence

1919

2020

8051 Architecture: Salient features8051 Architecture: Salient features 8 bit CPU with registers A and B8 bit CPU with registers A and B 16 bit Program Counter and data pointer DPTR16 bit Program Counter and data pointer DPTR 8 bit Program Status Word8 bit Program Status Word 8 bit Stack Pointer8 bit Stack Pointer Internal RAM 128 bytesInternal RAM 128 bytes

4 Registers banks, each containing 8 Registers4 Registers banks, each containing 8 Registers16 bytes, may be addressed at the bit level16 bytes, may be addressed at the bit level8 bytes of General Purpose memory8 bytes of General Purpose memory

Internal ROM 4KInternal ROM 4K 32 I/O pins as 4 eight bit ports: P0-P332 I/O pins as 4 eight bit ports: P0-P3 2 sixteen bit timer/counters: T0 and T12 sixteen bit timer/counters: T0 and T1 Full duplex serial data receiver/transmitter: SBUFFull duplex serial data receiver/transmitter: SBUF Control registers: TCON, TMOD, SCON, PCON, IP AND IEControl registers: TCON, TMOD, SCON, PCON, IP AND IE 2 external and 3 internal interrupt sources2 external and 3 internal interrupt sources Oscillator and clock circuits.Oscillator and clock circuits.

2121

Pin Description of the 8051Pin Description of the 8051

2222

8051 Hardware Connections : Crystal Connection to 80518051 Hardware Connections : Crystal Connection to 8051

C2

30pF

C1

30pF

XTAL2

XTAL1

GND

Using a quartz crystal oscillator ( Frequency 11.0592 MHz) We can observe the frequency on the XTAL2 pin.

Pin 18

Pin 20

Pin 19

2323

Pins of 8051Pins of 8051 Vcc （ pin 40 ）：

– Vcc provides supply voltage to the chip.

– The voltage source is +5V. GND （ pin 20 ）： ground XTAL1 and XTAL2 （ pins 19,18 ） RST （ pin 9 ）： reset

– It is an input pin and is active high （ normally low ） . The high pulse must be high at least 2 machine cycles.

– It is a power-on reset. Upon applying a high pulse to RST, the microcontroller will

reset and all values in registers will be lost.

2424

Pins of 8051Pins of 8051

/EA （ pin 31 ）： external access

– There is no on-chip ROM in 8031 and 8032 .

– The /EA pin is connected to GND to indicate the code is stored externally.

– /PSEN ＆ ALE are used for external ROM.

– For 8051, /EA pin is connected to Vcc.

– “/” means active low. /PSEN （ pin 29 ）： program store enable

– This is an output pin and is connected to the OE pin of the ROM.

2525

Pins of 8051Pins of 8051

ALE （ pin 30 ）： address latch enable– It is an output pin and is active high.– 8051 port 0 provides both address and data.– The ALE pin is used for de-multiplexing the address

and data by connecting to the G pin of the 74LS373 latch.

I/O port pins– The four ports P0, P1, P2, and P3.– Each port uses 8 pins.– All I/O pins are bi-directional..

2626

Pins of I/O PortPins of I/O Port

The 8051 has four I/O ports– Port 0 （ pins 32-39 ）： P0 （ P0.0 ～ P0.7 ）– Port 1 （ pins 1-8 ）： P1 （ P1.0 ～ P1.7 ）– Port 2 （ pins 21-28 ）： P2 （ P2.0 ～ P2.7 ）– Port 3 （ pins 10-17 ）： P3 （ P3.0 ～ P3.7 ）– Each port has 8 pins.

Named P0.X （ X=0,1,...,7 ） , P1.X, P2.X, P3.X Ex ： P0.0 is the bit 0 （ LSB ） of P0 Ex ： P0.7 is the bit 7 （ MSB ） of P0 These 8 bits form a byte.

Each port can be used as input or output (bi-direction).

2727

Power-On RESET CircuitPower-On RESET Circuit

30 pF

30 pF

8.2 K

10 uF

+

Vcc

11.0592 MHz

EA/VPPX1

X2

RST

31

19

18

9

2828

Hardware Structure of I/O PinHardware Structure of I/O Pin

Each pin of I/O ports

– Internal CPU bus ： communicate with CPU

– A D latch store the value of this pin D latch is controlled by “Write to latch”

– Write to latch ＝ 1 ： write data into the D latch

– 2 Tri-state buffer ： TB1: controlled by “Read pin”

– Read pin ＝ 1 ： really read the data present at the pin TB2: controlled by “Read latch”

– Read latch ＝ 1 ： read value from internal latch

– A transistor M1 gate Gate=0: open Gate=1: close

P89V51 RD2 : P89V51 RD2 : Electrical Specs.( Threshold Electrical Specs.( Threshold

Voltages)Voltages)

2929

P89V51RD2 : Timing Specs.P89V51RD2 : Timing Specs.

3131

3232

A Pin of Port 1A Pin of Port 1

8051 IC

D Q

Clk Q

Vcc

Load(L1)

Read latch

Read pin

Write to latch

Internal CPU bus

M1

P1.X pinP1.X

TB1

TB2

P0.x

3333

Writing “1” to Output Pin P1.XWriting “1” to Output Pin P1.X

D Q

Clk Q

Vcc

Load(L1)

Read latch

Read pin

Write to latch

Internal CPU bus

M1

P1.X pinP1.X

8051 IC

2. output pin is Vcc1. write a 1 to the pin

1

0 output 1

TB1

TB2

3434

Writing “0” to Output Pin P1.XWriting “0” to Output Pin P1.X

D Q

Clk Q

Vcc

Load(L1)

Read latch

Read pin

Write to latch

Internal CPU bus

M1

P1.X pinP1.X

8051 IC

2. output pin is ground1. write a 0 to the pin

0

1 output 0

TB1

TB2

3535

Reading “High” at Input PinReading “High” at Input Pin

D Q

Clk Q

Vcc

Load(L1)

Read latch

Read pin

Write to latch

Internal CPU bus

M1

P1.X pin

P1.X

8051 IC

2. MOV A,P1

external pin=High1. write a 1 to the pin MOV

P1,#0FFH

1

0

3. Read pin=1 Read latch=0 Write to latch=1

1

TB1

TB2

3636

Reading “Low” at Input PinReading “Low” at Input Pin

D Q

Clk Q

Vcc

Load(L1)

Read latch

Read pin

Write to latch

Internal CPU bus

M1

P1.X pin

P1.X

8051 IC

2. MOV A,P1

external pin=Low1. write a 1 to the pin

MOV P1,#0FFH

1

0

3. Read pin=1 Read latch=0 Write to latch=1

0

TB1

TB2

You can not Get Logic 1 withYou can not Get Logic 1 withHeavy Load and Weak Pull-upHeavy Load and Weak Pull-up

3737

Is it too much?Is it too much?- it’s the beginning -- it’s the beginning -

3838

LOAD

LOADINGEFFECT( SOURCE IS INPROBLEM

3939

A Pin of Port 0A Pin of Port 0

8051 IC

D Q

Clk Q

Read latch

Read pin

Write to latch

Internal CPU bus

M1

P0.X pinP1.X

TB1

TB2

P1.x

4040

Port 0 with Pull-Up ResistorsPort 0 with Pull-Up Resistors

P0.0P0.1P0.2P0.3P0.4P0.5P0.6P0.7

DS5000

8751

8951

Vcc10 K

Port 0

4141

AddressLines

Bi-DirectionalData Lines

4242

Instruction:MOV A,# 3CH

743C

Data 5Chis in FlashMemory

4343

Instruction:MOV A,3CH

Data is 7F hex

At RAM Address3C hex - -

ACC data will be 7F h

E53C

4444

8580A0

Instruction: MOV p2,p0Mov address, address85

4545

Port 3 Alternate FunctionsPort 3 Alternate Functions

8051 PROG. MEMORY8051 PROG. MEMORY

4646

8051 DATA MEMORY8051 DATA MEMORY

4747

4848

Registers of 8051

4949

RAM memory space allocation in the 8051

7FH

30H

2FH

20H

1FH

17H

10H

0FH

07H

08H

18H

00HRegister Bank 0

(Stack )Register Bank 1

Register Bank 2

Register Bank 3

Bit-Addressable RAM

Scratch pad RAM

Prof. Cherrice TraverProf. Cherrice TraverEE/CS-152: Microprocessors and Microcontrollers

Address ModesAddress Modes Bit-Oriented Data TransferBit-Oriented Data Transfer – transfers between individual bits. – transfers between individual bits. SFRs with addresses ending in 0 or 8 are bit-addressable. (80, 88, 90, 98, SFRs with addresses ending in 0 or 8 are bit-addressable. (80, 88, 90, 98,

etc)etc) Carry flag (C) (bit 7 in the PSW) is used as a single-bit accumulatorCarry flag (C) (bit 7 in the PSW) is used as a single-bit accumulator RAM bits in addresses 20-2F are bit addressableRAM bits in addresses 20-2F are bit addressable

Examples of bit transfers of special function register bits:Examples of bit transfers of special function register bits:mov C, P0.0mov C, P0.0 ; C ; C bit 0 of P0 bit 0 of P0

Bit addressable Area of RAMBit addressable Area of RAM

mov R5,0fahmov R5,0fah ANL A,#08HANL A,#08H mov c,23h.2 mov c,23h.2 ; Data from RAM location ; Data from RAM location

; 23hex bit .2 is transferred to carry ; 23hex bit .2 is transferred to carry

mov 35.7,cmov 35.7,c ; Data from Carry Flag bit is transferred ; Data from Carry Flag bit is transferred ; to RAM location 35 decimal bit .7 i.e. ; to RAM location 35 decimal bit .7 i.e.

; 23H; 23H Mov p0.1 , c Mov p0.1 , c ; Carry bit is transferred to Port 0 bit .1; Carry bit is transferred to Port 0 bit .1 EndEnd ( NOTE : RAM Loactions 20 hex to 2f hex are Bit ( NOTE : RAM Loactions 20 hex to 2f hex are Bit

Addressable Area ).Addressable Area ).5151


Bit Addressable MemoryBit Addressable Memory20h – 2Fh (16 locations X 8-bits = 128 bits)

7F 78

1A

10

0F 08

07 06 05 04 03 02 01 00

27

26

25

24

23

22

21

20

2F

2E

2D

2C

2B

2A

29

28

Bit addressing:mov C, 1Ahormov C, 23h.2

5353

Stack in the 8051Stack in the 8051

The register used to access the stack is called SP (stack pointer) register.

The stack pointer in the 8051 is only 8 bits wide, which means that it can take value 00 to FFH. When 8051 powered up, the SP register contains value 07.

7FH

30H

2FH

20H

1FH

17H10H

0FH

07H

08H

18H

00HRegister Bank 0

(Stack )Register

Bank 1

Register Bank 2

Register Bank 3

Bit-Addressable RAM

Scratch pad RAM


StacksStacks

pushpop

stack

stack pointer

Go do the stack exercise…..

5555

TimersTimers

There are TWO general purpose 16 bit timersThere are TWO general purpose 16 bit timers

TIMER MODES:TIMER MODES:MODE 0MODE 0

MODE 1MODE 1

MODE 2MODE 2

MODE 3MODE 3

5656

TIMER MODE 0TIMER MODE 0

Setting timer X mode bits to 00 in the TMOD Setting timer X mode bits to 00 in the TMOD registers results in using THX register as an registers results in using THX register as an 8 bit counter and TLX as a 5 bit counter; 8 bit counter and TLX as a 5 bit counter; pulse input is divided by 32d in TL so that pulse input is divided by 32d in TL so that TH counts the original oscillator frequency TH counts the original oscillator frequency by a total 384d. by a total 384d.

5757


SIMILAR TO MODE 0 EXCEPT tlx IS SIMILAR TO MODE 0 EXCEPT tlx IS CONFIGURED AS A FULL 8 BIT CONFIGURED AS A FULL 8 BIT COUNTERCOUNTER

5858


The TLX is used as an 8 bit counter and The TLX is used as an 8 bit counter and THX is used to hold a value that is loaded THX is used to hold a value that is loaded into TLX every time TLX overflows from into TLX every time TLX overflows from FFH to 00H.FFH to 00H.

5959


Timer 0 in mode 3 becomes two completely Timer 0 in mode 3 becomes two completely separate 8 bit counters. Time 1 may work in separate 8 bit counters. Time 1 may work in Mode 0, 1 and 2.Mode 0, 1 and 2.

6161

TMOD RegisterTMOD Register: :

Gate : When set, timer only runs while INT(0,1) is high.

C/T : Counter/Timer select bit.

M1 : Mode bit 1. M0 : Mode bit 0.

6262

The Timer Control (TCON), Special Function Register:The Timer Control (TCON), Special Function Register:

TF1: Timer 1 overflow flag. Set when timer rolls from all 1 s to 0

TR1: Timer 1 run control bit. Set to 1 by program to enable count.

TF0: Timer 0 overflag. Set when timer rolls from all 1 s to 0

TR0: Timer 0 run control bit. Set to 1 by program to enable count.

6363

IE1: External interrupt 1 edge flag. Set to 1 when H to L IE1: External interrupt 1 edge flag. Set to 1 when H to L edge signal is received on port 3 pin 3.3 ( INT1)edge signal is received on port 3 pin 3.3 ( INT1)

IT1: External interrupt 1 signal type control bit. Set to 1 by IT1: External interrupt 1 signal type control bit. Set to 1 by program to enable external interrupt 1 to be triggered by a program to enable external interrupt 1 to be triggered by a falling edge signal. Set to 0 by by program to enable a low falling edge signal. Set to 0 by by program to enable a low level signal on external interrupt 1 to generate and level signal on external interrupt 1 to generate and interrupt.interrupt.

IE0: External interrupt 0 edge flag. External interrupt 1 IE0: External interrupt 0 edge flag. External interrupt 1 edge flag. edge flag. Set to 1 when H to L edge signal is received Set to 1 when H to L edge signal is received on port 3 pin on port 3 pin 3.2(INT0)3.2(INT0)

IT0: External interrupt 0 signal type control bitIT0: External interrupt 0 signal type control bit

TCON

PCB: 89c51 Microcontroller PortsPCB: 89c51 Microcontroller Ports

6464

Port 3 Port 1

Port 2 Port 0

ATMEL 89c51 Microcontroller

PCB: 89c51 Microcontroller CardPCB: 89c51 Microcontroller Card

6565

ResistorArray (10K)

Micro-controller

Crystal 11.0592 MHz

Burge StripHeader

Capacitors30 pF

Port 3 Port 1

Port 2 Port 0


PCB: 89c51 Microcontroller CardPCB: 89c51 Microcontroller Card

6666

ResistorArray (10K)

Micro-controller

Crystal 11.0592 MHz

Burge StripHeader

Capacitors30 pF

Port 3 Port 1

Port 2 Port 0


6767

PCB: 89c51 Microcontroller PCB: 89c51 Microcontroller CardCard

Pin 1 of 89c51

Pin 20 Of 89c51

Pin 21Of89c51

Pin 40 of 89c51


Where is Clock Circuitry ?Where is Clock Circuitry ?

6868

Clock Circuitrysection


Clock circuitry componentsClock circuitry components

6969

Crystal 11.0592 MHz

Two Capacitors33 pF


LED Array Card : To Port 0LED Array Card : To Port 0

7070

LED Array card to PORT 0


Interfacing DIP Switch & LED ArrayInterfacing DIP Switch & LED Array

7171

PORT 0DIP Switch

PORT 1LED Array

ATMEL Microcontroller 89c51

Stepper Motor InterfacingStepper Motor Interfacing

7272

Stepper Motor InterfacingP1.0 to P1.3PORT 1 thru’ULN 2003 Driver

StepperMotor


P.C. Serial(RS-232) Interfacing with uC 89c51P.C. Serial(RS-232) Interfacing with uC 89c51

7373

Pin 10,11 to MAX232

RS232 port of P.C.


Embedded system-Spiral ModelEmbedded system-Spiral Model

7474

What is Embedded System?What is Embedded System?

7676

Microcontroller W/S Microcontroller W/S

LAB. EXPERIMENTSLAB. EXPERIMENTS

7777

OVERVIEW DATA TRANSFERSOVERVIEW DATA TRANSFERS

InstructionSOURCE OF DATA

DESTINATIONOF DATA

ADDRESSING MODE

MOV A,#56H FLASH MEMORY

ACCUMULATOR

IMMEDIATE

MOV A,56H RAM LOCATION56H

ACCUMULATOR

DIRECT

MOV A,R1 RAM REGISTER R1

ACCUMULATOR

REGISTER

MOV A,@ 56H RAM LOCATION WHOSEADDRESS IS STORED AT LOCATION 56H

ACCUMULATOR

REGISTER INDIRECT

Tuesday, April 11, 2023Tuesday, April 11, 2023

Mahdi Hassanpour


Infinite LoopsInfinite Loops

Start: mov C, p3.7Start: mov C, p3.7

mov p1.6, Cmov p1.6, C

sjmp Startsjmp Start

Microcontroller application programs are almost always infinite loops!

Program for Blinking LEDs on Program for Blinking LEDs on PORT 0PORT 0

Include 89c51.mcInclude 89c51.mc Loop:Loop: Mov a,#55hMov a,#55h Mov p0,aMov p0,a Jmp loopJmp loop

8080

LED In Sinking & Sourcing ModeLED In Sinking & Sourcing Mode

8181

Lab. Experiment:Lab. Experiment:Alternately Blink LEDs at PORT 1 considering DelayAlternately Blink LEDs at PORT 1 considering Delay

MOV A,#55HMOV A,#55H MOV P1,AMOV P1,A LOOP:LOOP: MOV R5,#0FFH MOV R5,#0FFH REPEAT3: REPEAT3: MOV R3,#0FFHMOV R3,#0FFH REPEAT2:REPEAT2: Delay LoopDelay Loop DJNZ R3,REPEAT2DJNZ R3,REPEAT2 DJNZ R5,REPEAT3DJNZ R5,REPEAT3 CPL ACPL A MOV P1,AMOV P1,A JMP LOOPJMP LOOP

8282

Lab. Experiment: Lab. Experiment: Connect LED Array to PORT 1. Scroll LEDs Connect LED Array to PORT 1. Scroll LEDs

one by one , in sinking mode one by one , in sinking mode MOV A,#80HMOV A,#80H MOV P1,AMOV P1,A LOOP: LOOP: MOV R5,#0FFHMOV R5,#0FFH REPEAT3: REPEAT3: MOV R3,#0FFHMOV R3,#0FFH REPEAT2:REPEAT2: Delay LoopDelay Loop DJNZ R3,REPEAT2DJNZ R3,REPEAT2 DJNZ R5,REPEAT3DJNZ R5,REPEAT3 RR ARR A MOV P1,AMOV P1,A JMP LOOPJMP LOOP

8383

Experiment 2 : DIP Switch & LED array InterfacingExperiment 2 : DIP Switch & LED array Interfacing

Assumption : DIP Switch interfaced to Assumption : DIP Switch interfaced to PORT 0 & LED Array interfaced to PORT 1.PORT 0 & LED Array interfaced to PORT 1.

MOV A,#0FFHMOV A,#0FFH AGAIN: AGAIN: MOV A,P0MOV A,P0 MOV P1,AMOV P1,A JMP AGAINJMP AGAIN

8484

Lab. Experiment : Generation of Square Lab. Experiment : Generation of Square Wave Wave

LOOP:LOOP: SETB P1.0SETB P1.0 MOV R5,#3FHMOV R5,#3FH CALL DELAYCALL DELAY CLR P1.0CLR P1.0 MOV R5,#0FFHMOV R5,#0FFH CALL DELAYCALL DELAY JMP LOOPJMP LOOP

8585

DELAY:NOPDJNZ R5,AGAINRET

ULN 2003 DRIVER : For Driving ULN 2003 DRIVER : For Driving Stepper MotorStepper Motor

8686

Lab. Experiment : Stepper Motor ControllerLab. Experiment : Stepper Motor Controller

C1 EQU P1.0C1 EQU P1.0 C2 EQU P1.1C2 EQU P1.1 C3 EQU P1.2C3 EQU P1.2 C4 EQU P1.3C4 EQU P1.3 DATA EQU P1DATA EQU P1

MOV DATA , #00HMOV DATA , #00H MOV A,#88HMOV A,#88H ENDLESS:ENDLESS: RR ARR A MOV DATA,AMOV DATA,A CALL DELAYCALL DELAY JMP ENDLESSJMP ENDLESS

8787

DELAY:MOV R7,#0FFHAGAIN:NOPNOP

DJNZ R7,AGAIN

RET

A simple project using A simple project using AT89C51AT89C51

8989



; 23hex bit .2 is transferred to ; 23hex bit .2 is transferred to carry carry

mov 35.7,cmov 35.7,c ; Data from Carry Flag bit is transferred ; Data from Carry Flag bit is transferred ; to RAM location 35 decimal bit .7; to RAM location 35 decimal bit .7

Mov p0.1 , c Mov p0.1 , c ; Carry bit is transferred to Port 0 bit .1; Carry bit is transferred to Port 0 bit .1 EndEnd ( NOTE : RAM Loactions 20 hex to 2f hex are Bit ( NOTE : RAM Loactions 20 hex to 2f hex are Bit

Addressable Area ).Addressable Area ). 9191

MicrocontrollersMicrocontrollers

9292

8051 Pin-out8051 Pin-out

9393

RST – ResetRST – ResetHIGH for 2 clock cyclesHIGH for 2 clock cycles

Resets registers and Resets registers and

program counter (to 0000h) program counter (to 0000h)

for an orderly startup.for an orderly startup.

Program Status Word (PSW)Program Status Word (PSW)

Pulse width modulatorPulse width modulator Generates pulses with Generates pulses with

specific high/low timesspecific high/low times Duty cycle: % time highDuty cycle: % time high

– Square wave: 50% Square wave: 50% duty cycleduty cycle

Common use: control Common use: control average voltage to average voltage to electric deviceelectric device– Simpler than DC-Simpler than DC-

DC converter or DC converter or digital-analog digital-analog converterconverter

– DC motor speed, DC motor speed, dimmer lightsdimmer lights

Another use: encode Another use: encode commands, receiver commands, receiver uses timer to decodeuses timer to decode

9696

clk

pwm_o

25% duty cycle – average pwm_o is 1.25V

clk

pwm_o

50% duty cycle – average pwm_o is 2.5V.

Fall 2004Fall 2004

Stepper motor controllerStepper motor controller

Red AWhite A’Yellow B

Black B’

MC3479P 1

5

4

3

2

7

8

6

16

15

14

13

12

11

10

9

Vd

A’

A

GND

Bias’/Set

Clk

O|C

Vm

B

B’

GND

Phase A’

CW’/CCW

Full’/Half Step

Sequence A B A’ B’1 + + - -2 - + + -3 - - + +4 + - - +5 + + - -

Stepper motor: rotates Stepper motor: rotates fixed number of degrees fixed number of degrees when given a “step” signalwhen given a “step” signal– In contrast, DC motor just In contrast, DC motor just

rotates when power applied, rotates when power applied, coasts to stopcoasts to stop

Rotation achieved by Rotation achieved by applying specific voltage applying specific voltage sequence to coilssequence to coils

Controller greatly Controller greatly simplifies this simplifies this

Fall 2004Fall 2004

Stepper motor with controller Stepper motor with controller (driver)(driver)

2 A’ 3 A

10 7

B 15B’ 14

MC3479PStepper Motor Driver 8051

P1.0P1.1

StepperMotor

CLK

CW’/CCW

The output pins on the stepper motor driver do not provide enough current to drive the stepper motor. To amplify the current, a buffer is needed. One possible implementation of the buffers is pictured to the left. Q1 is an MJE3055T NPN transistor and Q2 is an MJE2955T PNP transistor. A is connected to the 8051 microcontroller and B is connected to the stepper motor.

Q2

1K

1KQ1

+V

A B

void main(void){

*/turn the motor forward */ cw=0; /* set direction */ clk=0; /* pulse clock */ delay(); clk=1;

/*turn the motor backwards */ cw=1; /* set direction */ clk=0; /* pulse clock */ delay(); clk=1;

}

/* main.c */

sbit clk=P1^1;sbit cw=P1^0;

void delay(void){ int i, j; for (i=0; i<1000; i++) for ( j=0; j<50; j++) i = i + 0;}

Fall 2004Fall 2004

Stepper motor without controller Stepper motor without controller (driver)(driver)

StepperMotor

8051

GND/ +VP2.4

P2.3P2.2P2.1P2.0

A possible way to implement the buffers is located below. The 8051 alone cannot drive the stepper motor, so several transistors were added to increase the current going to the stepper motor. Q1 are MJE3055T NPN transistors and Q3 is an MJE2955T PNP transistor. A is connected to the 8051 microcontroller and B is connected to the stepper motor.

Q2

+V

1KQ1

1K

+V

A

B

330

/*main.c*/sbit notA=P2^0;sbit isA=P2^1;sbit notB=P2^2;sbit isB=P2^3;sbit dir=P2^4;

void delay(){ int a, b; for(a=0; a<5000; a++) for(b=0; b<10000; b++) a=a+0;}

void move(int dir, int steps) {int y, z; /* clockwise movement */ if(dir == 1){ for(y=0; y<=steps; y++){ for(z=0; z<=19; z+4){ isA=lookup[z]; isB=lookup[z+1]; notA=lookup[z+2]; notB=lookup[z+3]; delay(); } } }

/* counter clockwise movement */ if(dir==0){ for(y=0; y<=step; y++){ for(z=19; z>=0; z - 4){ isA=lookup[z]; isB=lookup[z-1]; notA=lookup[z -2]; notB=lookup[z-3]; delay( ); } } }}void main( ){ int z; int lookup[20] = { 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0 }; while(1){ /*move forward, 15 degrees (2 steps) */ move(1, 2); /* move backwards, 7.5 degrees (1step)*/ move(0, 1); }}

4 register banks4 register banks

General user RAMGeneral user RAM

Special Function Registers (SFR)Special Function Registers (SFR)

100100

Intel 8051 RAM

8051 SFRs8051 SFRs

Blue: related to the I/O ports Blue: related to the I/O ports

Yellow: control the configuration of 8051 Yellow: control the configuration of 8051

Green: auxiliary SFRs Green: auxiliary SFRs

101101

102102

103103

Block Diagram of 8051 Block Diagram of 8051 MicrocontrollerMicrocontroller

104104

Schematic for Microcontroller Schematic for Microcontroller BoardBoard

105105

106106

8051 Block Diagram8051 Block Diagram

107107

8051 Family State Sequence8051 Family State Sequence

108108

RAM RAM

109109

110110

111111

Using 7 Segment DisplayUsing 7 Segment Display

112112

113113

114114

115115



; 23hex bit .2 is transferred to ; 23hex bit .2 is transferred to carry carry

mov 35.7,cmov 35.7,c ; Data from Carry Flag bit is transferred ; Data from Carry Flag bit is transferred ; to RAM location 35 decimal bit .7; to RAM location 35 decimal bit .7

Mov p0.1 , c Mov p0.1 , c ; Carry bit is transferred to Port 0 bit .1; Carry bit is transferred to Port 0 bit .1 EndEnd ( NOTE : RAM Loactions 20 hex to 2f hex are Bit ( NOTE : RAM Loactions 20 hex to 2f hex are Bit

Addressable Area ).Addressable Area ). 116116

Rotating Universal /DC Motor in Clockwise & Anticlockwise Rotating Universal /DC Motor in Clockwise & Anticlockwise using Microcontroller by Sensing positionusing Microcontroller by Sensing position

117117

Micro-Con-troller

89c51

TANK

2 C.O. /

DPDT Relay

DC Motor

REEDSensor

Assembly Code for Sensing PositionAssembly Code for Sensing Position

MOV P1,#FFh ; port1 as a input portMOV P1,#FFh ; port1 as a input port MOV A,P1MOV A,P1 LOOP:LOOP: MOV R1,P1MOV R1,P1

IF R1 = # FEh then ; 1111 1110IF R1 = # FEh then ; 1111 1110 SETB P2.0SETB P2.0 END IFEND IF MOV R2,P1MOV R2,P1

IF R2=#FDh then ; 1111 1101IF R2=#FDh then ; 1111 1101 CLR P2.0CLR P2.0 END IFEND IF

JMP LOOPJMP LOOP118118

Micro-Controller89c51

Pin 1P1.0

Pin 2P1.1

P 2.0

From sensor 1st

From sensor 2nd

Micro controller-8051

Education

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