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Contents:Contents:

IntroductionIntroductionBlock Diagram andBlock Diagram and Pin Description of the 8051Pin Description of the 8051

RegistersRegisters

Memor mapping in 8051Memor mapping in 8051

!tack in the 8051!tack in the 8051

I"# Port ProgrammingI"# Port Programming$imer$imer

InterruptInterrupt


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Why do we need to learnWhy do we need to learn

Microprocessors/controllers?Microprocessors/controllers? The microprocessor is the core of

computer systems.

Nowadays many communication, digitalentertainment, portable devices, arecontrolled by them.

A designer should now what types ofcomponents he needs, ways to reduceproduction costs and product reliable..


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The necessary tools for aThe necessary tools for a

microprocessor/controllermicroprocessor/controller

&'(# &entral 'rocessing (nit

$/)# $nput /)utput

*us# Address bus + !ata bus

Memory# AM + )M

Timer

$nterrupt

%erial 'ort

'arallel 'ort


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R&M R#M

I"#

Port$imer

!erial

C#M

PortMicrocontroller

CP%

A smaller computer

On-chip RAM, ROM, I/O ports(((

!ampleMotorola"s $#)), Intel"s #%*), +ilo"s +# an' PIC )$

A sinle chip

Microcontroller .


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Microprocessor

CPU is stan'-alone, RAM,

ROM, I/O, timer are separate

'esiner can 'eci'e on theamount of ROM, RAM an'

I/O ports(

e!pansie

ersatility

eneral-purpose

Microcontroller

0 CPU, RAM, ROM, I/O an'

timer are all on a sinle chip

0 fi! amount of on-chip ROM,RAM, I/O ports

0 for applications in 1hich cost,

po1er an' space are critical

0 sinle-purpose

Microprocessor s( Microcontroller


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m&e''e' system means the processor is em&e''e' into that

application(

An em&e''e' pro'uct uses a microprocessor or microcontroller to 'o

one tas2 only(

In an em&e''e' system, there is only one application soft1are that is

typically &urne' into ROM(

!ampleprinter, 2ey&oar', i'eo ame player

m&e''e' System


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)( meetin the computin nee's of the tas2 efficiently an' cost

effectiely

0 spee', the amount of ROM an' RAM, the num&er of I/O ports

an' timers, si3e, pac2ain, po1er consumption

0 easy to upra'e

0 cost per unit

4( aaila&ility of soft1are 'eelopment tools

0 assem&lers, 'e&uers, C compilers, emulator, simulator,

technical support

5( 1i'e aaila&ility an' relia&le sources of the microcontrollers(

6hree criteria in Choosin a Microcontroller


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Block DiagramBlock Diagram

CP%

#n'chip

R&M

#n'chip

R#M for

program

code

( I"# Ports

$imer 0

!erial

Port#!C

Interrupt

Control

)*ternal interrupts

$imer 1

$imer"Counter

Bus

Control

$*D R*DP0 P1 P+ P,

&ddress"Data

Counter

Inputs


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Pin Description of the 8051Pin Description of the 8051

-0123

45-6-----0-1-2-3-4-56

06543210

-6543210-

'-.6'-.-'-.'-.'-.0'-.1'-.2

'-.3%T78!9'.67T8!9'.-

7T69'.07T-9'.1

8TA:8TA:-

;N!

7$NT69'.

7$NT-9'.

7!9'.37W9'.2


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Wednesday, %eptemb Mahdi "assanpour

&reated by bibe&reated by bibe


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7iure 8a9( 6A: Connection to #%*)7iure 8a9( 6A: Connection to #%*)

&

,0p-

&-

,0p-

8TA:

8TA:-

;N!

Usin a ;uart3 crystal oscillator


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Pins of 8051Pins of 8051 +"(+"(

RS6pin = reset

> It is an input pin an' is actie hih normally lo1 (

6he hih pulse must &e hih at least 4 machine cycles(

> It is a po1er-on reset(

Upon applyin a hih pulse to RS6, the

microcontroller 1ill reset an' all alues in reisters

1ill &e lost( Reset alues of some #%*) reisters


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-igure ./ Po2er'#n R)!)$ Circuit-igure ./ Po2er'#n R)!)$ Circuit

5% p7

5% p7

#(4 ?

)% u7

@

cc

))(%*=4 MB3

A/PP)

4

RS6

5)

)=

)#

=


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Pins of 8051Pins of 8051 ,"(,"(

/Apin 5) e!ternal access> 6here is no on-chip ROM in #%5) an' #%54 (

> 6he /A pin is connecte' to GN to in'icate the co'e is

store' e!ternally(

> /PSN A: are use' for e!ternal ROM(

> 7or #%*), /A pin is connecte' to cc(

> D/E means actie lo1(

/PSNpin 4=proram store ena&le

> 6his is an output pin an' is connecte' to the O pin of the

ROM(


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Pins of 8051Pins of 8051 ("(("(

A:pin 5% a''ress latch ena&le

>It is an output pin an' is actie hih(

>#%*) port % proi'es &oth a''ress an' 'ata(

>6he A: pin is use' for 'e-multiple!in the a''ressan' 'ata &y connectin to the G pin of the F:S5F5latch(

I/O port pins

>6he four ports P%, P), P4, an' P5(

>ach port uses # pins(

>All I/O pins are &i-'irectional((


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Bar'1are Structure of I/O PinBar'1are Structure of I/O Pin

ach pin of I/O ports

> Internal CPU &us communicate 1ith CPU

> A latch store the alue of this pin

latch is controlle' &y D Rea' latch ) rea' alue from internal latch> A transistor M) ate

Gate%. open

Gate). close


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! :atch! :atch##


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Other PinsOther Pins

P), P4, an' P5 hae internal pull-up resisters(

>P), P4, an' P5 are not open 'rain(

P% has no internal pull-up resistors an' 'oes not

connects to cc insi'e the #%*)(>P% is open 'rain(

>Compare the fiures of P)( an' P%((

Bo1eer, for a prorammer, it is the same to proramP%, P), P4 an' P5(

All the ports upon RS6 are confiure' as output(


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Port % 1ith Pull-Up ResistorsPort % 1ith Pull-Up Resistors

P%(%P%()P%(4P%(5P%(P%(*P%($P%(F

D!5000

8351

8451

cc10 6

Port0


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Port 5 Alternate 7unctionsPort 5 Alternate 7unctions

)F)FRRP5(FP5(F

)$)$


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R)!)$ alue of !ome 8051 Registers:R)!)$ alue of !ome 8051 Registers:

0000DP$R0003!P

0000P!7

0000B0000&CC

0000PC

Reset alueRegister

R&M are all ero


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Registers

A

H

R%

R)

R5

R

R4

R*

RF

R$

PB P:

PC

P6R

PC

Some #%*) )$-&it Reister

Some #-&itt Reisters of

the #%*)


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Memory mapping in 8051Memory mapping in 8051

ROM memory map in 8051 family

%%%%B

%777B

%%%%B

)777B

%%%%B

F777B

#F*)

A6#=C*)#F*4

A6#=C*4

0

S*%%%-54

4

from Atmel Corporationfrom allas Semicon'uctor


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RAM memory space allocation in the 8051

F7B

5%B

47B

4%B

)7B

)FB)%B

%7B

%FB

%#B

)#B

%%BReister Han2 %

(Stac2)Register Bank 1

Reister Han2 4

Reister Han2 5

Hit-A''ressa&le RAM

Scratch pa' RAM


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!tack in the 8051!tack in the 8051

6he reister use' to accessthe stac2 is calle' !P 8stac2

pointer9 reister(

6he stac2 pointer in the #%*)is only # &its 1i'e, 1hichmeans that it can ta2e alue%% to 77B(


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Timer #Timer #


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)


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TM)! egisterTM)! egister##

;ate # When set, timer only runs while $NT76,-9 ishigh.

&/T #&ounter/Timer select bit.

M- # Mode bit -. M6 # Mode bit 6.


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T&)N egister#T&)N egister#

T>-# Timer - overflow flag.

T-# Timer - run control bit.

T>6# Timer 6 overflag.

T6# Timer 6 run control bit.

$=-# =ternal interrupt - edge flag. $T-# =ternal interrupt - type flag.

$=6# =ternal interrupt 6 edge flag.

$T6# =ternal interrupt 6 type flag.

$nterrupt #$nterrupt #


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$nterrupt #$nterrupt #


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$nterrupt =nable egister #$nterrupt =nable egister #

=A :Global enable/disable. --- : ndefined.

=T #=nable Timer interrupt. =% #=nable %erial port interrupt. =T- #=nable Timer - interrupt.

=8- #=nable =ternal - interrupt. =T6 # =nable Timer 6 interrupt. =86 # =nable =ternal 6 interrupt..

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