Tìm Hiểu Về Vi Điều Khiển Pic 16f877A Và Ứng Dụng (1)

5/24/2018 T m Hi u V Vi i u Khi n Pic 16f877A V ng D ng (1)

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Li ni u

Ngy nay cng vi s pht trin khng ngng ca khoa hc k thut, th k

thut s em li cho con ngi nhng thnh tu to ln gip cho con ngi

d dng t c mc ch ca mnh trong mi thit k. Ha nhp cng xuhng vi iu khin khng nh c v th vng chc ca mnh trong

mi ng dng. in hnh trong cng ngh o lng v iu khin bng my

tnh c bit l vic o nhit v iu khin cc h thng. Trong lnh vc

sn xut cng nghip nhit c tc ng tr c tip n cht lng u ra

nh trong qu trnh gia cng v liu nhit nh hng n chnh xc tnh

gin n vt liu. Trong qu trnh nung sy nh nung gch th nhit nhhng n cht lng sn phm. Trong y hc nhit nh hng ti kt qu

nghin cu.Trong cuc sng nhit nh hng ti cht lng v bo qun

lng thc. Vi cc yu cu em xin thit k ti: c nhit hin th

ln led 7 thanh dng cm bin IC tch hp LM35


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Chng I: Tm hiu chung vvi iu khinVi iu khin l mt my tnh c tch hp trn mt chip, n thng c

sdng iu khin cc thit bin t. Vi iu khin thc cht l mt h

thng bao gm mt vi xl c hiu xut dng v gi thnh thp ( khc vicc bvi xl a nng dng trong my tnh) kt hp vi cc khi ngoi vi

nh bnh, cc m un vo/ ra, cc m un bin i ssang tng tv

tng tsang s, my tnh th cc m un thng c xy dng bi

cc chip v mch ngoi.

1.1 Cu trc vi iu khinHu ht cc vi iu khin ngy nay c xy dng da trn kin trc Von

Neumann, kin trc ny nh ngha bn thnh phn cn thit ca mt h

thng nhng. Nhng thnh phn ny l li CPU, bnhchng trnh (thng

thng l ROM hoc bnhFlash ) bnhdliu (RAM ), mt hoc vi b

nh thi v cc cng vo/ra giao tip vi cc thit bngoi vi v cc mi

trng bn ngoi tt ccc khi ny c thit ktrong mt vi mch tch

hp. Vi iu khin khc vi cc bvi xl a nng chl n c thhot

ng chvi vi vi mch htrbn ngoi.

Ngoi cu trc Von Neumann cn c cu trc Harvard, cu trc Harvard

tch ri bnhdliu v bnhchng trnh, nn tc xl cao hn v

dung lng ca 2 ng truyn c thkhc nhau.

Vi iu khin thng c sdng xy dng cc h thng nhng. N

xut hin kh nhiu trong cc dng cin t, thit bin, my git, l vi

sng, in thoi, u lc DVD, thit ba phng tin, dy chuyn tng

1.2 Phn lo1.2.1 di thanh ghi

Da vo di ca cc thanh ghi cc lnh ca VK m ngi ta chia ra

cc loi VK 8bt, 16bt hay 32bit

Cc loi VK 16bit do c lch ln hn ln cc tp lnh cng nhiu hn

phong ph hn. Tuy nhin bt c chng trnh no vit bng VK 16 bit

chng ta u c thvit trn VK 8 bit vi chng trnh thch hp.


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1.2.2 Cu trc RISC v CISCVXL hoc VK CISC l VK c tp lnh phc tp. Cc VK ny c mt

s lng ln cc lnh nn gip cho ngi lp trnh c th linh hot v d

dng hn khi vit chng trnh.VK RISC l VK c tp lnh n gin. Chng c mt slng nhcc

lnh n gin. Do , chng i hi phn cng t hn, gi thnh thp hn, v

nhanh hn so vi CISC. Tuy nhin n i hi ngi lp trnh phi vit cc

chng trnh phc tp hn nhiu lnh hn.

1.2.3 Kin trc Harvard v kin trc Vonneumann

Kin trc Harvard sdng bnhring bit cho chng trnh v d liu.

Bus a chv bus dliu c lp vi nhau nn qu trnh truyn nhn dliu

n gin hn.

Kin trc Vonneumann s dng chungb nh cho chng trnh v d liu.

iu ny lm cho VK gn nh hn, gi thnh nh hn.

1.3 Chc nng ca vi iu khin1.3.1 Chc nng ca vi x l

Trong nhng thp nin cui th k XX, t s ra i ca cng ngh bn dn,

k thut in t c s pht trin vt bc. Cc thit b in t sau

c tch hp vi mt cao v rt cao trong cc din tch nh, nh vy cc

thit b in t nh hn v nhiu chc nng hn. Cc thit b in t ngy

cng nhiu chc nng trong khi gi thnh ngy cng r hn, chnh v vy in

t c mt khp mi ni.Bc t ph mi trong cng ngh in t, cng ty

tr tui Intel cho ra i b vi x l u tin. t ph ch: " l mt kt

cu logic m c th thay i chc nng ca n bng chng trnh ngoi ch

khng pht trin theo hng to mt cu trc phn cng ch thc hin theo

mt s chc nng nht nh nh trc y. Tc l phn cng ch ng vai tr

th yu, phn mm (chng trnh) ng vai tr ch o i vi cc chc

nng cn thc hin. Nh vy vi x l c s mm do ha trong cc chc nngca mnh. Ngy nay vi x l c tnh ton rt cao v kh nng x l rt ln.


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Vi xl c cc khi chc nng cn thit ly dliu, xl dliu v

xut dliu ra ngoi sau khi xl. V chc nng chnh ca Vi xl chnh

l xl dliu, chng hn nh cng, tr, nhn, chia, so snh.v.v..... Vi xl

khng c khnng giao tip trc tip vi cc thit bngoi vi, n chc khnng nhn v xl dliu m thi.

vi xl hot ng cn c chng trnh km theo, cc chng trnh ny

iu khin cc mch logic v t vi xl xl cc dliu cn thit theo

yu cu. Chng trnh l tp hp cc lnh xl dliu thc hin tng

lnh c lu trtrong bnh, cng vic thc hnh lnh bao gm:

Nhn lnh t b nh, gii m lnh v thc hin lnh sau khi gii m. thc hin cc cng vic vi cc thit b cui cng, chng hn iu khin ng

c, hin th k t trn mn hnhi hi phi kt hp vi x l vi cc mch

in giao tip vi bn ngoi c gi l cc thit b I/O ( nhp/xut ) hay cn

gi l cc thit b ngoi vi. Bn than cc vi x l khi ng mt mnh khng

c nhiu hiu qu s dng, nhng khi l mt phn ca ca mt my tnh th

hiu qu s dng ca Vi x l l rt ln, phc tp i hi phi x l mtlng ln cc php tnh phc tp, c tc nhanh. Chng hn nh cc h

thng sn xut t ng trong cng nghip, cc tng i in thoi, hoc cc

robot c kh nng hot ng phc tp v.v...

1.3.2 T Vi x l n Vi iu khinB Vi x l c kh nng vt bc so vi cc h thng khc v kh nng

tnh ton, x l, v thay i chng trnh linh hot theo mc ch ngi dng,

c bit hiu qu i vi cc bi ton v h thng ln.Tuy nhin i vi cc

ng dng nh, tm tnh ton khng i hi kh nng tnh ton ln th vic

ng dng vi x l cn cn nhc. Bi v h thng d ln hay nh, nu dng vi

x l th cng i hi cc khi mch in giao tip phc tp nh nhau. Cc

khi ny bao gm b nh cha d liu v chng trnh thc hin, cc

mch in giao tip ngoi vi xut nhp v iu khin trli, cc khi ny

cng lin kt vi vi x l th mi thc hin c cng vic. H thng c


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to ra kh phc tp, chim nhiu khng gian, mch in phc tp v vn

chnh l trnh ngi thit k. Kt qu l gi thnh sn phm cui cng rt

cao, khng ph hp p dng cho cc h thng nh.

V mt s nhc im trn nn cc nh ch to tch hp mt t b nh vmt s mch giao tip ngoi vi cng vi vi x l vo mt IC duy nht c

gi l Microcontroller-Vi iu khin. Vi iu khin c kh nng tng t nh

kh nng ca vi x l, nhng cu trc phn cng dnh cho ngi dng n

gin hn nhiu. Vi iu khin ra i mang li s tin li i vi ngi dng,

h khng cn nm vng mt khi lng kinthc qu ln nh ngi dng vi

x l, kt cu mch in dnh cho ngi dng cng tr nn n gin hnnhiu v c kh nng giao tip trc tip vi cc thit b bn ngoi. Vi iu

khin tuy c xy dng vi phn cng dnh cho ngi s dng n gin

hn, nhng thay vo li im ny l kh nng x l b gii hn (tc x l

chm hn v kh nng tnh ton t hn, dung lng chng trnh b gii hn).

Thay vo , Vi iu khin c gi thnh r hn nhiu so vi vi x l, vic s

dng n gin, do n c ng dng rng ri vo nhiu ng dng c chcnng n gin, khng i hi tnh ton phc tp.

1.4 Ngn ng lp trnh, cng c lp trnh1.4.1 Ngn ng lp trnh.

Lp trnh vi x l ngn ng thng dng l ngn ng lp trnh ASM v

ngn ng C .Ngn ng lp trnh ASM hay lp trnh hp ng l ngn ng lp

trnh trc tip cho vi iu khin ( lp trnh trc tip ) cn ngn ng C hay cn

gi l lp trnh hng i tng n gn vi ngn ng con ngi hn . iu

ny c ngha l vi ASM ngi lp trnhra lnh trc tip thng qua ngn ng

cu lnh c tnh rng buc cn ngn ng C s dng cc cu trc iu kin v

vng lp theo mun .Ni v ngn ng C th u im ca ngn ng C l n

d hiu nhng cu trc li di v phc tp so vi ngn ng ASM


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1.4.2 Cng c lp trnha) V phn cng:

Mt iu khng th thit l mt b timer tch hp trong VK.N c

nhim v to n v thi gian.(C ngha l mt chu k hot ng ca h thngc chia nh thnh cc n v thi gian).B nh chng trnh ln

cha cc m lnh .Ngoi m lnh ca cc task cong m lnh ca Kernel .B

nh RAM cng l mt vn rt hn ch ca VK v mi ln chuyn ng

cnh th ton b ng cnh ca mt Task c lu vo mt ngn xp trong

RAM.Chng ta c cng nhiu task th cn cnh nhiu ngnxp kiu ny.

b) V phn mm:C hai cng c lp trnh cho VK l ngn ng bc thp

(Assembly) v ngn ng bc cao (C ,basic)


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a) Chng II: Tm hiu vi iu khin Pic 16F877A v ng dngKhi iu khin Pic 16F877A

PIC l vit tt ca Programable Intelligent Computer c th tm

dch l my tnh thng minh khtrnh do hng General Instrument t tn chovi iu khin u tin ca h: PIC 1650 c thit kdng lm cc thit b

ngoi vi cho vi iu khin CP 1600. Vi iu khin ny sau c nghin

cu pht trin thm v t hnh thnh nn dng vi iu khin PIC ngy nay

Pic 16F877A l dng Pic ph bin nht hin nay ( mnh v tnh

nng, 40 chn, bnhcho hu ht cc ng dng thng thng ) cu trc

tng qut ca Pic 16F877A:+ 8K Plash Rom

+ 368 byte Ram

+ 256 byte EEPROM

+ 5 port ( A,B,C,D,E ) vo ra vi tn hiu c lp.

+ 2 bnh thi 8 bit ( timer0 v timer2 )

+ 1 bnh thi 16 bit ( timer 1 ) c thhot ng trog chtit kimnng lng ( Sleep mode ) vi xung clock bn ngoi

+ 2 bCCP ( Capture/Compare/PWM)

+ 1 bbin i AD 10 bit vi 8 ng vo

+ 2 bso snh tng t( compartor )

+ 1 bnh thi gim st ( Watchdog timer )

+ 1 cng song song 8 bit vi cc tn hiu iu khin

+ 1 cng ni tip

+ 15 ngun ngt

+ Np chng trnh bng cng ni tip ICSP ( In-Circuit Serial

Programming )

+ c chto bng cng nghCMOS

+ 35 tp lnh c di 14 bit

+ Tng hot ng ti a 20MHz


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+ Pic hot ng ta cn cp ngun cho Pic ngoi ra c ththm vo

bdao ng thch anh v nt reset.

2.1 S khi vi iu khin Pic 16F877A


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S khi ca PIC16F877A gm cc khi

+ ALUArithmetic Logic Unit

+ Khi b nh cha chng trnhFlash Program Memory.

+ Khi b nh cha d liu EPROM Data EPROM.+ Khi b nh file thanh ghi RAM RAM file Resgiter

+ Khi gii m lnh v iu khin Instruction Decode Control.

+ Khi thanh ghi c bit.

+ Khi ngoi vi timer

+ Khi giao tip ni tip

+ Khi chuyn i tn hiu tng t sang s - ADC+ Cc khi port xut nhp

2.2 c im vi iu khin Pic 16F877A

y l vi iu khin thuc h Pic16Fxxx gm 35 lnh vi di 14 bit.

Mi lnh u c thc hin trong 1 chuk xung clock, tc hot ng ti

a cho php l 20MHz vi 1 chu k lnh l 200ns. B nh chng trnh 8Kx

14 bit, b nh d liu 368x8 byte RAM v b nh d liu EEPROM vidung lng 256x8 byte. S PORT I/O l 5 vi 33 pin I/O. C 8 knh chuyn

i A/D.

2.2.1 Cc c tnhngoivi bao gmcc khi chc nng:

+ Timer0: B m 8 bit vi b chia tng 8 bit

+ Timer1: B m 16 bit vi b chia tng c th thc hin chc nng m

da vo xung clock ngoi vi ngay khi vi iu khin hot ng ch sleep.

+ Timer2: B m 8 bit vi b chia tng s, b postcaler.

o Hai b capture , so snh, iu ch rng xungo Cc chun giao tip ni SSP ( Synchronous serial port ), SPI v I2Co Chun giao tip ni tip song song PSP ( Parallel Slave Port ) vi cc

chn iu khin RD, WR, CS bn ngoi.


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2.2.2 Cc c tnh Analog:8knh chuyn i ADC 10 bit

2b so snh

B nh flash vi kh nng ghi xa c 100.000 lnB nh EEPROM vi kh nng ghi xa c 1.000.000 ln

D liu bnh EEPROM c th lu tr trn 40 nm

Kh nng t np chng trnh vi s iu khin ca phn mm

Np chng trnh ngay trn mch in ICSP ( In Circuit Serial

Programming ) thng qua 2 chn

Watchdog timer vi b dao ng trongChc nng bo mt m chng trnh

Ch sleep

C th hot ng vi nhiu dng Oscillator khc nhau

2.2.3Cc cng xut nhp ca Pic 16F877ACng xut nhp chnh l phng tin ma vi iu khin dng tng tc

vi th gii bn ngoi. S tng tc ny rt a dng v thng qua s tngtc ,chc nng ca vi iu khin c th hin r rng.

Vi iu khin PIC 16F877A c 5 cng xut nhp PORTA, PORTB,

PORTC, PORTD v PORTE.

PORT A (RPA) bao gm 6 I/O y l cc chn 2 chiu c th xut v

nhp,chc nng xut nhp c iu khin bi thanh ghi TRISA (a ch

85h). Mun xc lp 1 chn trong thanh ghi TRISA l input ta set bit

tng ng trong thanh ghi TRISA v mn c 1 chn output ta clearbit

tng ng trong thanh ghi. Thao tc ny hon ton tng t vi PORT v

cc thanh ghi iu khin tng ng.

Bn cnh PORTA cn l ng ra ca b ADC,b so snh,ng vo

Analog,ng vo xung clock Timer0 v ng vo ca b giao tip MSSP.

Cc thanh ghi TRISA bao gm:

PORTA (a ch 05h):cha gi tr cc chn I/O trong PORTA


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TRISA (a ch85h): iu khin xut nhp.

CMCON (a ch 9Ch): thanh ghi iu khin b so snh.

ADCON1 (a ch 9Fh):thanh ghi iu khin ADC

PORTB

PORTB(RPB) bao gm 8 chn I/O,thanh ghi iu khin xut nhp tng

ng l TRISB. Bn cnh c 1 s chn ca PORTB dng np chng

trnh cho vi iu khin vi cc ch np khc nhau. PORTB cn lin quan

n ngt ngoi vi v Timer0. PORTB cn c tch hp chc nng in tr

ko ln c iu khin bi chng trnh

Cc thanh ghi PORTB bao gm:PORTB (a ch 06h,106h):cha gi tr cc chn trong PORTB.

TRISB (a ch 86h,186h):iu khin xut nhp.

OPTION_REG (a ch 81h,181h):iu khin ngt ngoi vi ton b Timer0.

PORTC

PORTC(RPC)gm 8 chn I/O,thanh ghi iu khin xut nhp tng ng l

TRISC,bn cnh PORTC cn cha cc chn chc nng ca b sosnh,Timer1,b PWM,v cc chun giao tip ni tip I2C,SPI,SSP,USART

Cc thanh ghi iu khin:

PORTC (a ch 07h):cha gi tr cc chn trong PORTC.

TRISC (a ch 87h):iu khin xut nhp.

PORTD

PORTD(RPD) gm 8 chn I/O,thanh ghi iu khin xut nhp tng ng l

TRISD,PORTD cn l cng xut d liu ca chun giao tip PSP

Cc thanh ghi:

Thanh ghi PORTD (a ch 08h):cha gi tr cc chn trong PORTD

TRISD (a ch 88h)iu khin xut nhp


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PORTE

PORTE(RPE) gm 3 chn I/0,thanh ghi iu khin xut nhp tng ng l

TRISE. Cc chn PORTE c ng vo analog,bn cnh PORTE cn l

cc chn iu khin ca chun giao tip PSPCc thanh ghi:

PORT (a chi 09h) cha gi tr cc chn trong PORTE.

TRISE (a ch 89h) iu khin xut nhp v xc lp cc thng s cho

chun PSP.

ADCON1 thanh ghi iu khin khi ADC.

2.3 Cc thit b ngoi vi2.3.1 Cm binLM35

a)Cm bin LM35 l b cm bin nhit mch tch hp chnh xc cao

m in p u ra ca n t l tuyn tnh vi nhit theo thang

Celsius. Chng cng khng yu cu cn chnh ngoi v vn chng c

cn chnh

b) c im chnh ca cm bin LM35

+ in p u vo t4V n 30V

+ phn gii in p u ra l 10mV/oC

+ chnh xc cao 25 C l 0.5 C

+ Trkhng u ra thp 0.1 cho 1mA ti

2.3.2Mn hnh hin thLCDNgy nay, thit bhin thLCD (Liquid Crystal Display) c s

dng trong rt nhiu cc ng dng ca VK.LCD c rt nhiu u im so vi

cc dng hin thkhc: N c khnng hin thk tadng, trc quan (ch,

sv k tha), ddng a vo mch ng dng theo nhiu giao thc giao

tip khc nhau, tn rt t ti nguyn hthng v gi thnh r


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2.4 Chc nng cc chn ca vi iu khin Pic 16F877A

o Chn OSC1/CLK1 (13): Ng vo kt ni vi dao ng thch anh hoc g vonhn xung clock t bn ngoi.

o Chn OSC1CLK1 (14): Ng ra dao ng thch anh hoc ng ra cp xungclock

o Chn (1) c 2 chc nng: ng vo reset tch cc mc thpo Chn OSC1/CLK1 (13) : Ng vo kt ni vi dao ng thch anh hoc vo

nhn xung clock t bn ngoi.


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o Chn OSC2/CLK (14) : ng ra dao ng thch anh hoc ng ra cp xungclock.

o Chn MCLR/Vpp(1) c 2 chc nng: MCLR ng vo reset tch cc thp, Vppng vo nhn in p lp trnh khi lp trnh cho PIC

o Chn RA0/AN0(2), RA1/(3),RA2/An2(3): c 2 chc nng l RA0,1,2xut/nhp s; AN 0,1,2 ng vo tng t ca knh th 0,1,2.

o Chn RA2/AN2/VREF-/CVREF+(4): Xut nhp s/ ng vo tng t caknh th 2/ ng vo in ap chun thp ca b AD/ ng vo in p chun

cao ca b AD.

o Chn RA3/AN3/VREF+(5):xut nhp s/ ng vo tng t knh 3/ng voin p chun (cao) ca b AD.

o Chn RA4/TOCK1/C1OUT(6): xut nhp s/ ng vo xung clock bn ngoicho Timer 0/ ng ra b so snh 1.

o Chn RA5/AN4/SS/C2OUT(7): xut nhp s/ ng vo tng t knh 4/ ngvo chn la SPI ph/ ng ra b so snh 2

oChn RB0/INT(33): xut nhp s/ ng tn hiu ngt ngoi.

o Chn RB1(34), RB2(35): xutnhp s.o Chn RB3/PGM (36); xut nhp s/ cho php lp trnh in p thp ICSP.o Chn RB4(37), RB5(38): xut nhp so Chn RB6/PGC(39): xut nhp s/ mch g ri v xung clock lp trnh ICSP.o Chn RB7/PGD(40): xut nhp s/ mch g ri v d liu lp trnh ICSPo Chn RC1/T1OSI/CCP2(16): xut nhp s/ ng vo b dao ng Timer 1/

ng va Capture 2, ng ra compare2, ng ra PWM2.

o Chn RC2/CCP1(17): xut nhp s/ ng vo Capture1, ng ra compare1, ngra PWM1.

o Chn RC3/SCK/SCL(18): xut nhp s/ ng vo xung clock ni tip ng b, ng ra ca ch I2C.

o Chn RC4/SDI/SDA(23): xut nhp s/ d liu vo SPI/ xut nhp d liuI2c


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o Chn RC5/SDO (24):xut nhp s/ d liu ra SPI.o Chn RC6/TX/CK(25): xut nhp s/ truyn bt ng b USART/ xung ng

b USART.

o Chn RC7/RX/DT(26): xut nhp s/ nhn bt ng b USART.o Chn RD0-7/PSP0-7(19-30): xut nhp s/ d liu port song song.o Chn RE0/ RD/AN5(8): xut nhp s/ iu khin port song song/ ng vo

tng t 5

o Chn RE1/WR/AN6(9): xut nhp s/ iu khin khi port song song/ ng votng t knh th 6.

o Chn RE2/CS/AN7(10): xut nhp s/ chn chn la iu khin port songsong/ng vo tng t knh th 7.

o Chn V (11,32) v Chn RB4(37), RB5(38): xut nhp s.o Chn RB6/PGC(39): xut nhp s/ mch g ri v xung clock lp trnh

ICSP.

2.5 Thanh ghi

2.5.1Thanh ghi chc nng c bit SFR

y l cc thanh ghi c s dng bi CPU hoc c dng thit lp v

iu khin cc khi chc nng c tch hp bn trong vi iu khin. C th

phn thanh ghi SFR lm 2 loi: thanh ghi SFR lin quan n cc chc nng

bn trong ( CPU )v thanh ghi SCF dng thit lp v iu khin cc khi

chc nng bn ngoi (v d nh ADC, PWM,). Phn ny s cp n cc

thanh ghi lin quan n cc thanh ghi lin quan n cc chc nngbn trong. Cc thanh ghi dng thit lp v iu khin cc khi chc

nng s c nhc n khi ta cp ti cc khi chc nng


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Thanh ghi STATUS( 03h, 83h, 103h, 183h ): thanh ghi cha kt qu thc

hin php ton ca khi ALU, trng thi reset v cc bit chn bank cn truy

xut trong b nh d liu.

Thanh ghi OPTION_RED (81h, 181h ): thanh ghi ny cho php c v

ghi, iu khin chc nng pull-up ca cc chn trong PORTB, xc lp cc

tham s v xung tc ng, cnh tc ng ca ngt ngoai vi v b m

Timer0.

Thanh ghi INTCON(0Bh, 8Bh, 10Bh, 18Bh ): thanh ghi cho php c v

ghi, cha cc bit iu khin v cc bit c hiu khi Timer0 b trn, ngt ngoi

vi RB0/INT v ngt interput on change ti cc chn ca PORTB

Thanh ghi PIE1(8Ch): cha cc bit iu khin chi tit ngt ca cc khi

chc nng ngoiThanh ghi PIR1(0Ch ) cha cngt ca cc khi chc nng

ngoi vi.

Thanh ghiPIE2( 8Dh ) cha cc bit iu khin cc ngt ca cc khi chc

nng CCP2, SSP bus ngt ca bso snh v ngt ghi vo bnhEEPROM


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Thanh ghi PIR2 (0Dh ) cha cc cngt ca cc khi chc nng ngoi vi,

cc cngt ny cho php bi cc bit iu khin cha trong thanh ghi PIE2

2.5.2 Thanh ghi mc ch chung GPRCc thanh ghi ny c th c truy xut trc tip hoc gin tip thng qua

thanh ghi FSG ( File Select Register ). y l cc thanh ghi d liu thng

thng ngi s dng c th ty theo mc ch chng trnh m c th dngcc thanh ghi ny cha cc bin s, hng s, kt qu hoc cc tham s

phc v cho chng trnh

2.6Ngn ng lp trnhS ra i ca mt lot vi iu khin i km vi vic pht trin phn mm

ng dng cho vic lp trnh cho con vi iu khin . Vi iu khin ch hiu

v lm vic vi hai con s 0 v 1. Ban u vic lp trnh cho VK l lmvic vi dy cc con s 0 v 1. Sau ny khi kin trc ca VK ngy cng

phc tp,s lng thanh ghi lnh nhiu ln, vic lp trnh vi dy s 0 v 1

khng cn ph hp na, i hi ra i mt ngn ng mi thay th. V ngn

ng lp trnh Assembly, sau ny khi ngn ng C ra i nhu cu dng ngn

ng C thay cho ASM trong vic m t cc lnh lp trnh cho Vi iu khin

mt cch ngn gn v d hiu hn dn n s ra i ca nhiu chngtrnh son tho v bin dch C cho Vi iu khin: Keil C, HT-PIC, MikroC,


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Chng III: Cc loi cm bin v ng dng trong

mch vi iu khin

3.1 m3.1.1 Khng hr202 cm bin m:o Hr202 m cm bin khng c to thnh t vt liu polyme

hu c, n c rt tt m cm bin phm vi, hiu sut n nh,

di hn s dng, c th c s dng trong kho, xe t, kim

sot cht lng khng kh trong nh, xy dng t ng ha, y t,

h thng iu khin cng nghip v nhiu ng dng nh nghin

cu khoa hc.

o Thng s k thut: cc thng s ( ti 1kHz ) n v: ohm tmhot ng 20..95%rh 0.. 60? m pht hin chnh xc ca

&Plusmn, 5%rh

M t

1. C th pht hin m mi trng xung quanh2. iu chnh nhy ( th hin trong mu xanh Potentiometer

k thut s iu chnh )

3. in p hot ng 3.3v-5v.4. u ra t a) 5 in p u ra tng t5. K thut s chuyn i kt qu u ra ( 0 v 1)6. L bulng c nh ci t d dng 7. Bng nh pcb kch thc: 3cm* 1.6cm8. S dng LM393 so snh chip

ng dng:


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S dng hin th nhit v m, kh quyn, gim st

mi trng, iu khin qu trnh cng nghip, nng nghip,

kh st cng c vv.

1. m khng m-un nhy cm nht vi mi trng.2. Khi mi trng bn ngoi m vt qu thit lp ngng,

cc m un d0 u ra thp.

3. dO k thut s u ra c th c kt ni trc tip vi viiu khin pht hin cao v thp, do pht hin mi

trng m thay i

4. C th li xe chuyn tip m-un trc tip, c th c baogm t kim sot chuyn i.

N cng c u ra tng t.

3.1.2Cm bin m HS1101

HS1101 l loi cm bin o m. chnh

xc +-2%. Dy nhit hot ng t -400C n

1000C. Cm bin HS1101 c s dng ph bin

trong cuc sng, ngoi ra n cn dng kt hp vi cm bin

DS18B20 dng o nhit .

Nguyn l hot ng: Cm bin HS1101 l cmbin in

dung. Khi m thay i in dung ca HS1101 thay i. Do

vy, o c m ngi ta thng ghp ni HS1101 v IC

NE555. Khi gi tr in dung ca HS1101 thay i th lm

thay i tn s u ra ca IC555. Nh vy ch cn o tn s u

ra l c th o c in dung ca HS1101.


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S ghp ni HS1101 vi NE555


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3.2 Cm bin nhit 3.2.1LM35

Cm bin LM 35

Gm 3 chn: + chn 1: chn ngun u vo Vcc

+ chn 2: chn u voVout

+ chn 3: chn ni t GNDCm bin LM35 l bcm

bin nhit mch tch hp chnh xc cao m in p u ra can tl

tuyn tnh vi nhit theo thang Celsius. Chng cng khng

yu cu cnchnh ngoi v vn chng c cn chnhc im

chnh ca cm bin LM35+ in p u vo t4V n 30V+

phn gii in p u ra l 10mV/oC+ chnh xc cao 25 C l


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0.5 C+ Trkhng u ra thp 0.1 cho 1mA tiDi nhit o c

ca LM35 l t-55 C - 150 C vi cc mc in p ra khc nhau.Xt

mt smc in p sau :- Nhit -55 C in p u ra -550mV-

Nhit 25 C in p u ra 250mV- Nhit 150 C in p u ra

1500mV.

3.2.2Cm bin PT1001.Cc thng sk thut ca dy o nhit PT100

a-Cc thng sc bn :

Dy cm bin nhit PT100 bao gm mt u d ng trc ng

knh 4mm v chiu di ng trl 30mm ,2 dy u ra c chiu di

70cm

Di nhit o c l t-200C n 500C

b-S cu to bn trong ca u d hnh tr


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in trca ng trRPT100 = RPT + R3 + R2

L2,L3 c ni vi 2 dy u ra

c-Nguyn tc hot ng

Khi c sthay i nhit trn u d th dn n sthay i in

trca ng tr.Mi gi trnhit khc nhau tng ng vi mi gi

trin trkhc nhau.10 C th o c gi trin tr

RPT100 =107,6 . Khi tng 1C th RPT tng sp x0,4

Chng IV: Thit khthng o nhit dng Pic 877A v

LM 35

4.1 Thit kphn cng4.1.1

S khi


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4.1.2 Khi ngun

a)S nguyn l

Khi Ngun

Khi Vi XL

Khi Cm

Bin

Khi Hin

Th

Khi Bn Phm Khi Cnh Bo


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b) La chn linh kinMch ngun cung cp in p cho hthng hot ng trong :

+ Bin p dng bin i in p xoay chiu thnh in p xoay

chiu in p thp cp cho mch chnh lu.

+ Chnh lu cu lm nhim vbiin i in p xoay chiu thnh 1

chiu.


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+ T c vai tr lc cc thnh phn nhiu (1000F, 100F, 1F)

+ IC 7805 c vai tr to ra in p 5v chun


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y l cch mc c bn ca IC h 78xx, nhng khng th thiu t

1000F vo 2 u Input v OutPut ca IC

4.1.3 Khi cm bin o lng nhit c th s dng nhiu loi cm bin khc nhau,

mi loi c u im ring ph hp vi tng

yu cu ring. i vi ti ny ch o nhit

mi trng bnh thng nn s dng

LM35 l ti u nht v: y l loi cm bin

c chnh xc cao tm hot ng tuyn tnh

t 0 1280C, tn hao cng sut thp.Cm bin nhit LM35 c vai

tr o nhit mi trng sau truyn tn hiu o c cho Pic

di dng in p,nhit tng hay gim 10C th LM35 cng tng

hay gim 10mv theo 10C.

LM35 c 3 chn,2 chn cp ngun( chn 1:cp ngun t 4v

20v,chn 3 ni GND),1 chn xut in p ra ty theo nhit ( chn2).


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Cc t tnh k thut khc

+LM35 c di nhit t -550C n 1500C, chnh xc 1,50C, u ra

10mv/10C

+Dng LM35 l dng mch tch hp cm bin chnh xc nhit ,c

in p ra t l thun vi nhit , do c li th hn so vi cm

bin nhit tuyn tnh hiu chun nh (0K) chng hn nhng dng

khng phi tr i 1 lng ln hng s in p t u ra phn chia

thang nhit thun tin hn.

+LM35 khng cn hiu chnh hay chnh sa a v nhit chnh xc nh 1/40C nhit trong phng v 3/40C trong khong

-55 n 1500C. Sai s thp v c vi mch iu chnh

+Tr khng u ra ca LM35 thp, u ra tuyn tnh v hiu chnh

chun xc gip c v kim sot mch d dng.

+N c s dng vi ngun 1 chiu, ch s dng 60A t ngun

nn nhit vi mch tng rt t, thp hn 0,10C trong khng kh.

Common Cathode: Loi K chung

Common Anode: Loi A chung.


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Led 7 on l 1cng c thng dng dng hin th cc thng s

di dng cc s t 0 n 9. Mc d LCD gip ta th hin cc thng

s 1 cch linh ng hn nhng led 7 on vn c s dng nhiu

hn trong cng nghip do cc u th: t chu nh hng ca nhit ,

d tos ch v gc nhn rng

+Led 7 thanh bao gm 7 on led c nh du l cc k t a, b, c,

d, e, f, g, v 1 du chm thp phn k hiu l dp, ta c th xem led 7

on l 1 t hp gm 8 led, 8 led ny c 1 u anode hoc cathode

ni chung v c b tr theo 1 quy tt nht nh dng th hincc ch s

+C 2 lai led 7 on l: Loi Anode chung( cc Anode ca cc

led c ni chung) v loi Cathode chung( cc Cathode ca cc led

ni chung). Ty theo tng loi led m ta c cc phng php iu

khincc led trong t hp sng tt 1 cch thch hp.

+Vic iu khin sng tt c iu khin bng cch a d liu vo

cc chn a n g v chn dp, l cch hin th tng led. Trn th t,

tit kim s chn cn thit iu khin nhiu led cng lc,cc

chn d liu led s c ni song song vi nhau,cc chn chung

c dng iu khin cho led sng hay tt. Phng php hin th

da trn hin tng lu nh ca mt

Bng hin th led 7 on dnh cho loi Anode chung (cc led sng

mc d liu 0):

S hin th ln led

7 on

M hin th ln led

7 on dng nh

phn

M hin th ln led

7 on dng thp

lc phn


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h g f e d c b a

0 1 1 0 0 0 0 0 0 C0

1 1 1 1 1 1 0 0 1 F9

2 1 0 1 0 0 1 0 0 A4

3 1 0 1 1 0 0 0 0 B0

4 1 0 0 1 1 0 0 1 99

5 1 0 0 1 0 0 1 0 92

6 1 1 0 0 0 0 1 0 82

7 1 1 1 1 1 0 0 0 F8

8 1 0 0 0 0 0 0 0 80

9 1 0 0 1 0 0 0 0 90


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4.1.4 Khi vi x l

Nguyn l lm vic: Nhn tn hiu t cm bin qua bin i ADCca vi iu khin c chc nngchuyn i t tn hiu analog sang

digital. Diu khin, x l ri a ti khi hin th

Nt nhn v in tr to nt Reset cho Pic

Khi hin th


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Cc led u l A chung, cc chn a, b, c, d, e, f, g u l cc chn

d liu, t led hot ng c lp ,chn A chung c ni qua

Transistor v ni vi Vcc ca khi ngun

Khi tn hiu cc cc chn transistor l mc cao th cc led c

kch hot v nhn tn hiu stbvi xl hin thnhit ln

led 7 on.

4.2 Lp trnh phn mm


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4.2.1 Lu gii thut


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Khai bo bin

Khai bo chng trnhcon

c ADC

Cnh bo

Hin thled 7on

Kt thc

So

snh

gi trci t

Bt u


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4.2.2 S nguyn l


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4.2.3 S layout v mch in sn phm


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Chng V: Lp rpchto- chy thng dng

5.1 on code chng trnh

#include

#device pic16f877a*=16 ADC=10

#fuses XT,NOWDT,HS,PUT

#use delay (clock=4000000)

#use fast_io(e)

#use fast_io(b)

#use fast_io(c)

#use fast_io(d)

#byte portd=0x08

#byte portb=0x06

#byte portc=0x07

#bit rc0=0x07.0

#bit rc1=0x07.1


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#bit rc2=0x07.2

#bit rc3=0x07.3

#bit rc4=0x07.4

#bit rc5=0x07.5

#bit rc6=0x07.6

#bit rc7=0x07.7

#bit re0=0x09.0

#bit re1=0x09.1

#bit re2=0x09.2

int16

a[10]={0b11000000,0b11111001,0b10100100,0b10110000,0b10011001,0b10010010,0b10000010,0b11111000,0b10000000,0b10010000};

//int16

a[10]={0b00111111,0b00000110,0b01011011,0b01001111,0b01010110,0

b01101101,0b01111101,0b00000111,0b01111111,0b01101111};

int q,x,z,chuc,dv,chuc1,dv1;

void main()

{

set_tris_d(0);

set_tris_b(0);


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set_tris_c(0b11110000);

set_tris_e(0b000);

q=20;

z=0;

setup_ADC_ports(AN0_AN1_AN2_AN3_AN4);

setup_ADC(ADC_clock_div_2);

set_ADC_channel(0);

delay_ms(1000);

while(1)

{

if((rc4==0)&&(rc5==0))

{q=q+1;

delay_ms(20);}

if((rc4==0)&&(rc6==0))

{q=q-1;

delay_ms(20);}

if(x>=q)

{re0=1;}

if(x


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{re0=0;}

chuc1=q/10;

dv1=q%10;

portd=a[chuc1];

rc2=0;

rc3=1;

delay_ms(5);

portd=a[dv1];

rc2=1;

rc3=0;

delay_ms(5);

x=read_ADC()/2.048;

delay_ms(5);

chuc=x/10;

dv=x%10;

portb=a[chuc];

rc1=1;

rc0=0;

delay_ms(5);


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portb=a[dv];

rc1=0;

rc0=1;

delay_ms(5);

chuc1=q/10;

dv1=q%10;

portd=a[chuc1];

rc2=0;

rc3=1;

delay_ms(5);

portd=a[dv1];

rc2=1;

rc3=0;

delay_ms(5);

chuc=x/10;

dv=x%10;

portb=a[chuc];

rc1=1;

rc0=0;


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delay_ms(5);

portb=a[dv];

rc1=0;

rc0=1;

delay_ms(5);

delay_ms(5);

chuc1=q/10;

dv1=q%10;

portd=a[chuc1];

rc2=0;

rc3=1;

delay_ms(5);

portd=a[dv1];

rc2=1;

rc3=0;

delay_ms(5);

chuc1=q/10;

dv1=q%10;

portd=a[chuc1];


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rc2=0;

rc3=1;

delay_ms(5);

portd=a[dv1];

rc2=1;

rc3=0;

delay_ms(5);

chuc=x/10;

dv=x%10;

portb=a[chuc];

rc1=1;

rc0=0;

delay_ms(5);

portb=a[dv];

rc1=0;

rc0=1;

delay_ms(5);

chuc1=q/10;

dv1=q%10;


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portd=a[chuc1];

rc2=0;

rc3=1;

delay_ms(5);

portd=a[dv1];

rc2=1;

rc3=0;

delay_ms(5);

chuc=x/10;

dv=x%10;

portb=a[chuc];

rc1=1;

rc0=0;

delay_ms(5);

portb=a[dv];

rc1=0;

rc0=1;

delay_ms(5);

chuc1=q/10;


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dv1=q%10;

portd=a[chuc1];

rc2=0;

rc3=1;

delay_ms(5);

portd=a[dv1];

rc2=1;

rc3=0;

delay_ms(5);

chuc=x/10;

dv=x%10;

portb=a[chuc];

rc1=1;

rc0=0;

delay_ms(5);

portb=a[dv];

rc1=0;

rc0=1;

delay_ms(5);


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chuc1=q/10;

dv1=q%10;

portd=a[chuc1];

rc2=0;

rc3=1;

delay_ms(5);

portd=a[dv1];

rc2=1;

rc3=0;

delay_ms(5);

chuc=x/10;

dv=x%10;

portb=a[chuc];

rc1=1;

rc0=0;

delay_ms(5);

portb=a[dv];

rc1=0;

rc0=1;


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delay_ms(5);

chuc1=q/10;

dv1=q%10;

portd=a[chuc1];

rc2=0;

rc3=1;

delay_ms(5);

portd=a[dv1];

rc2=1;

rc3=0;

delay_ms(5);

chuc=x/10;

dv=x%10;

portb=a[chuc];

rc1=1;

rc0=0;

delay_ms(5);

portb=a[dv];

rc1=0;


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rc0=1;

delay_ms(5);

}

}

void analog()

{setup_ADC_ports(AN0_AN1_AN2_AN3_AN4);

setup_ADC(ADC_clock_div_2);

set_ADC_channel(0);

delay_ms(2000);}


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5.2 M phng

5.3 Hnh nh mch tht


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Kt lun

Hng pht trin ca mch c nhit sdng LM35 hin nay c s

dng trong cc l p trng, my iu ha, hthng bo chy trong cccng ssdng tm onhit thp.

Tuy nhin, do thi gian c hn cngnhtrnh vn cn nhiu hn ch,

nn ti vn cn nhiu thiu st, rt mong snggp kin ca thy

c v cc bn.

Cui cng chng em xin cm nthy gio PGS.TS Nguyn VnKhang

v cc thnh vin trong nhm tn tnh gip v chdn cho em v

mt kin thc, kthut ng thi ara cho em nhiu nh hng,

tng v to mi iu kin tt em c ththc hin ti trong thi gian

qua.

Documents

Tìm Hiểu Về Vi Điều Khiển Pic 16f877A Và Ứng Dụng (1)