Nhn xt ca gio vin hng dnThi Nguyn, ngy....thng 5 nm 2011. Gio vin hng dn(K ghi r h tn)Nhn xt ca gio vin chmThi Nguyn, ngy....thng 5 nm 2011 Gio vin hng dnB mn k thut my tnhnmnhcHthngnhng

(K ghi r h tn)GVHD Th.s. Nguyn Vn HuyTrang 1

GVHD Th.s. Nguyn Vn HuyTrong2

GVHD Th.s. Nguyn Vn HuyTrang 3

B mn k thut my tnhnmnhcHthngnhngMc lcLi ni u4Chng 1 . Phn tch h thng51.1 Tng quan v h thng n giao thng51.1.1. Mch dng IC s51.1.2. Vi mch dng k thut vi x l61.1.3. iukhin bng vi iu khin61.1.4. iu khin bng PLC61.2 Xc nh bi ton:81.2.1 Xc nh bi ton81.2.2 Yu cu ca bi ton thit k h thng iu khin n giao thng... 81.2.3 Gii php cng ngh101.2.4 Gii php thit k111.2.5 Yu cu v gii hn ca h thng iu khin n giao thng dng viiu khin11Chng 2. THIT K H THNG122.1 S khi tng quan ca h thng122.2 Gin thi gian132.3 S nguyn l142.3.1 Gii thch cc khi142.3.1.1. Bn phm142.3.1.2. Khi hin th .152.3.1.3 Khi iu khin trung tm162.3.1.3.1 Khi reset162.3.1.3.2 Khi to xung giao ng172.3.1.3.3 Khi vi iu khin172.3.1.4 Khi ngun182.3.2 Nguyn l hot ng182.4 S thut ton iu khin h thng n giao thng192.4.1. Chng trnh chnh192.4.2. Chngtrnh ngt212.4.3. Chng trnh led722B mn k thut my tnhnmnhcHthngnhng2.4.4 Chng trnh hin th232.4.5 Chng trnh set (hin th thi gian ci t cho h thng)232.5 La chn linh kin242.5.1 B iu khin 8 bit Pic 16F877A242.5.1.1 .Tng quan v pic242.5.1.2 Gii thiu v PIC 16F877A252.5.1.2.1.S chn...252.5.1.2.2. Cc thng s ca PIC 16F877A252.5.1.2.3. Cng xut nhp (I/O port)262.5.1.2.4. Timer292.5.2 LED 7 on332.5.3 Diot pht quang (LED)342.5.5 in tr352.5.6 T in352.5.7 Thch anh352.5.8 Nt bm (Button):352.5.9 IC n p 780535Chng 3. Xy dng h thong363.1 Chng trnh iu khin363.2. S mch in (layout)383.2.1. Mch iu khin trung tm393.2.2. Mch bn phm39Chng 4 Mch chy m phng40Kt lun41Ti liu tham kho42Li ni uNgy nay cng vi s pht trin i ln ca x hi, cc phng tin tham gia giao thng cng gia tng khng ngimgv h thong giao thng ngy cng phc tp . V vy m bo giao thng c an ton v thng sut th vic s dng cc h thong tn hiu iu khin v phn lung ti cc nt giao thng l rt cn thit.Nhn thay y vn rt st thc, vi nhng kin thc c trang b trong qu trnh hc tp v nghin cm ti trng i hc K Thut Cng Nghip chng em la chn ti: Thit k v m phng h thng iu khin n giao thng cho ng t ".Trong qu trnh thc hin n chng em nhn c s ch bo, hng dn tn tnh ca cc thy c trong khoa c bit l s ch bo ca thy ThS.Nguyn Vn Huy. Chng em xin trn thnh cm n s ch bo ca cc thy c!Trong khi thc hin n do kin thc cn hn ch cng nh chng em cha c nhiu iu kin i kho st thc t, vi mt khong thi gian ngan thc hin, do vy m n ca chng em cn nhiu thiu st mong cc thy c ng gp v b xung kin n ca chng em c hon thin hon Chng em xin chn thnh cm n!Ngy 25 thng 5 nm 2011.Nhm sinh vin thc hin:Trn Danh Long.Phm Quang Lun.Nguyn Tun Ninh.Chng 1 . Phn tch h thng.1.1 Tng quan v h thng n giao thng.Ngy nay cng vi s pht trin ca khoa hc k thut, x hi ngy cng vn minh v hin i, s pht trin th ngy mt i ln. Nhu cu v giao thng ngy cng tr nn cp thit, nht l trong cc khu vc thnh th. Do nhu cu ca i sng con ngi, c bit l nhu cu i li, cc loi phng tin giao thng tng mt cch chng mt. Ring ti Vit Nam s lng xe my trong nhng nm qua tng mt cch t bin, mt xe lu thng trn ng ngy mt nhiu, trong khi h thng ng x ti Vit Nam cn qu nhiu hn ch nn thng gy ra cc hin tng nh kt xe, ch tc giao thng, c bit l tai nn giao thng ngy cng ph bin tr thnh mi him ha cho nhiu ngi.V l do cc lut giao thng ln lt ra i v c a vo s dng mt cch lng l ri dn tr nn ph bin nh hin nay. Trong h thng n giao thng l cng c iu khin giao thng cng cng thc t v hiu qu c vai tr rt ln trong vic m bo an ton v gim thiu tai nn giao thng.1.1.1. Mch dng IC s.Vi mch dng IC s c cc u im sau: Tn hao cng sut b, mch c th dng pin hoc acquy. Gi thnh r . Mch n gin d thc hin. Song vi vic s dng k thut s rt kh khn trong vic thay i chng trnh. Mun thay i mt yu cu no ca chng trnh th buc lng phi thay i phn cng. Do mi ln phi lp li mch dn n tn km v kinh t m nhiu khi yu cu khng thc hin c nh phng php ny.Vi s pht trin mnh m ca ngnh k thut s c bit l cho ra i cc h vi x l, vi iu khin hay PLC gii quyt c nhng b tc v kinh t hn m phng php dng IC s kt ni li khng thc hin c.1.1.2. Vi mch dng k thut vi x l.Ngoi nhng u im nh lit k trong phng php dng IC s th phng php dng k thut vi x l con c nhng u im sau:Ta c th thay i chng trnh mt cch linh hot bng vic thay i phn mm trong khi phn cng khng thay i m mch dng IC s khng th thc hin c m nu c th thc hin c th cng cng nhc m ngi cng nhn cng kh tip cn, d nhm.S linh kin s dng trong mch t hnMch n gin hn so vi mch dng IC s. Song do phn cng ca vi x l ch s dng CPU n chp m khng c cc b nh Ram, Rom, cc b timer, h thng ngt. Nn vic vit chng trnh gp nhiu kh khn. Do vy hin nay khc phc nhng nhc im trn hin nay ngi ta thng dng b vi iu khin.1.1.3. iukhin bng vi iu khin.Ngoi nhng u im c ca hai phng php trn, phng php ny cn c nhng u im sau: Trong mch c th s dng ngay b nh trong i vi chng trnh c quy m nh, rt tin li m vi x l khng thc hin c. N c th giao tip ni tip trc tip vi my tnh m vi x l cng giao tip c nhng l giao tip song song nn cn c linh kin chuyn i d liu t song song sang ni tip giao tip vi my tnh. Do trong vi iu khin c s dng cc b timer, cc h thng ngt, cu lnh n gin nn vic lp trnh n gin, d thc hin. Ph hp vi kin thc ca sinh vin.1.1.4. iu khin bng PLCVi phng php iu khin bng PLC c nhng u im sau:Lm vic chc chn, lin tc v c tui th cao.Chc nng iu khin thay i d dng bng thit b lp trnh (my tnh, mn hnh) m khng cn thay i phn cng nu khng c yu cu thm bt cc thit b xut nhp.C th lm vic trong nhiu iu kin khc nhau.Hng dn ngi s dng n gin.Thi gian hon thnh mt chu trnh iu khin rt nhanh (vi ms). Tuy phng php ny c nhiu u im hn vi x l nhng vic p dng trong cc h thng nh l khng thch hp bi gi thnh rt cao.V d h thng n giao thng hin nay Thi Nguyn.(n ti ng t ng Minh cu giao nhau vi ng Hong Vn Th).

Hnh 1.1. Kho st s b ti ng t ng Minh cu.H thng n giao thng ti ng t ny gm :C 4 ct n.Thi gian sng ca cc n T = 28 giy,Tvng = 3 giy, Txanh = 25 giy. Hin th thi gian m ngc bng led ma trn.Gm 3 n tn hiu Xanh, ,Vng .Ch hot ng mt ch .Khng c ch phn ln xe cc thi im.Vi cc phng php nu trn y chng em la chn gii php iu khin bng vi iu khin bi y l phng php ph hp v ti u nht vi ti.1.2 Xc nh bi ton.1.2.1 Xc nh bi ton.Thit k h thng iu khin n giao thng ti ng t dng vi iu khin gm:4 ct n, c n tn hiu phn lung r tri trc.Hin th thi gian m li trn led 7 thanh v tr lng trng ct v trn nh ca ct n.1.2.2 Yu cu ca bi ton thit k h thng iu khin n giao thng.Trc tnh hnh phng tin tham gia giao thng ngy cng gia tng khng ngng v h thng giao thng nc ta ngy cng phc tp. Dn n tnh trng n tc v tai nn giao thng ngy cng gia tng. V vy m bo giao thng c an ton v thng sut th vic s dng cc h thng tn hiu iu khin v phn lung ti cc nt giao thng l rt cn thit. Vi tm quan trng nh vy h thng iu khin tn hiu giao thng cn m bo cc yu cu sau:m bo hot ng mt cch chnh xc,lin tc trong thi gian di. tin cy cao.m bo lm vic n nh, lu di.D quan st cho ngi i ng.

B mn k thut my tnhnmnhcHthngnhng

B mn k thut my tnhnmnhcHthngnhng

Chi ph nh, tit kim nng lng.

GVHD Th.s. Nguyn Vn HuyTrang 20

GVHD Th.s. Nguyn Vn HuyTrang 21

Gi s c mt ng t nh hnh v: \

Hnh 1.3. S m phng hot ng ca 1 h thng n giao thngC chu k n tn hiu T= T0 + Txanh + Tvno Trong :+T : L thi gian n sng.+Txanh L thi gian n xanh sng.+Tvng L thi gian n vng sng.+T = Txanh + Tvng. Xt ti thi im xt bi ton th:TH 1: n 1 xanh sng, n 2 sng.Khi h thng s cho php cc hng sau i: BIAID2A2DIB2C2C2Neu nh khng c phn ln, u tin hng i th d gy ra tai nn, n tc ti cc im giao ct (E, F) nh trn hnh v.T thc t ta thit k h thng c thm ch dn phn ln u tin cho cc hng nh sau: B1 n C2 v D2 n AI.

AIA20102

Hnh 1.2. M phng h thng nh thit kTH 2: n 1 vng sng v n 2 sng th cnh bo chuyn sang TH3.TH 3: n 1 sng v n 2 xanh sng th ta thit k tng t nh TH trn.1.2.3 Gii php cng ngh.Mch iu khin dng vi iu khin.Hin th thi gian dng led 7 on.n bo hng u tin dng n led n.Cc n bo dng led n.Bn phm reset v t thi gian cho h thng (thi gian 1 chu k n).1.2.4 Gii php thit k. Thit k mch m phng trn phn mm Proteus 7. Cng c lp trnh: phn mm PIC c Compiler (CCS). Thit k mch in bng phn mm Orcad 10.5.1.2.5 Yu cu v gii hn cua h thng iu khin n giao thng dng vi iu khin.Yu cu:+Hot ng chnh xc.+Mch in n gin.+Gi thnh thp tnh ng dng trong thc t cao.+C kh nng m rng.Gii hn:+C s sai lch trong thi gian so vi thi gian thc.+Kh lin kt vi cc h thng gim st chung ca h thng giaothng.Chong 2. THIT K H THNG2.1 S khi tng quan ca h thngKhi iu khin trung tm.KhiNgun.Khi hin thi. Hnh 2.1: S khi tng quan ca h thngTrong :Khi ngun:+ Ngun 1 chiu in p 5V cp cho vi iu khin, led hin th. Khi iu khin trung tm:+ Vi iu khin trung tm.+ Phn mm iu khin.Khi hin th:+ Led 7 on dng ngun 1 chiu hin th thi gian m ngc ca cc n.+ n phn ln, ch dn, n xanh, n vng, n : led n s dng ngun 1 chiu.Bn phm: bn phm t thi gian sng ca cc n, reset v bt u cho h thng hot ng.

xanh, i thns v r phi

vng

Hnh 2.2: Gin thi gian ca cc n2.2 Gin thi gian.xanh r tri

Ch thch:+ Trn gin thi gian c 3 n mu(Xanh, Vng, ) khi trng thi mc 1 tc l n sng, mc 0 n tt. Chu k sng tt cc n c lp i lp li nh trn gin .Th t sng Xanh => Vng => .C u tin khi n Xanh sng( u tin 1 v u tin 2 nh trnh by trn; Tg Xanh sng = Tg xanh r tri+ Tg xanh i thng v r phi).2.3 So nguyn l.LED 7 THANH HIEN THI THOI GIAN DEM NGUOC

_ bo IK Q1bi IVfK 03 b3 Ik 04 b IK 05 ICITrIdendoPtBCDGFG DP 121FTTOSCDEFG DP 1sTinOBCDEFG DP 12wn

Hnh 2.3: S nguyn l m phng h thng2.3.1 Gii thch cc khi.2.3.1.1. Bn phmR310K

0 oC1|o o' C2|o o'C3

MI MI 'M

R110KR210K10uF10uF10uF

Hnh 2.4 S nguyn l khi bn phmKhi nt c tc dng t thi gian (chu k ca n xanh) cho h thng hot ng v bt u chy h thng.Khi nt bm dc chng rung bng phn mm v phn cng + Chng rung bng phn mm: to khong thi gian tr gia cc ln bm phm

+ Chng rung bng phn cng ni thm t 1 OjLiF mc song song vi phm bmTrong h thng ny khi nt bm s c thit k ring trn 1 bo mch cng vi nt bm ca khi reset Nguyn l hot ng .Khi cp ngun nu nh khng c phm no c bm h thng s trng thi ch. Neu cc phm bm ni vi cng REO v RE1 ca PIC c bm (ng vi mc logic 0) th chng trnh s chy theo thi gian thit lp khi bm phm start (ni vi cng RE2). Neu cc phm SET TIME khng c bm th khi bm phm Start chng trnh s chy theo thi gian mc nh t vi chu k n l: R tri 10s,i thng 17s ,vng 3s v l 30s c hai nhnh.2.3.1.2. Khi hin thLED 7 THANH HIEN THI THOI GIAN DEM NGUOC

Hnh 2.5. S nguyn l khi hin th

n xanh sng ng vi cng RBO (ca nhnh 1) v RB4 (ca nhnh 2) c xut mc logic 1 m tranzitor Q1 v Q5 khuch i dng in v a vo n tn hiu (n led).n xanh i thng sng ng vi cng RB1 (ca nhnh 1) v RB5 (ca nhnh 2) c xut mc logic 1 m tranzitor 2 v Q6 khuch i dng in v a vo n tn hiu (n led).

n vng sng ng vi cng RB2 (ca nhnh 1) v RB6 (ca nhnh 2) c xut mc logic 1 m tranzitor Q3 v Q7 khuch i dng in v a vo n tn hiu (n led).n sng ng vi cng RB3 (ca nhnh 1) v RB7 (ca nhnh 2) c xut mc logic 1 m tranzitor Q4 v Q8 khuch i dng in v a vo n tn hiu (n led).Cc n tn hiu c ni chung m.Led 7 thanh l loi c ni chung anot. Mi ct n s c 2 led 7 thanh hin th thi gian m ngc. Chn anot chung ca cc led c iu khin thng qua cng RCO v RC1 (mc logic 1) cc thanh a,b,c ,d ,e ,f,g ca led c iu khin bng cng RD (mc logic 0) ca PIC (thanh a-RDO, thanh b-RDl, thanh C-RD2, thanh d-RD3, thanh e-RD4, thanh f- RD5, thanh g-RD6).Khi c tn hiu iu khin mc logic 1 chn RCO th led hng chc s c m v thanh no c ni vi mc 0 s sng (tn hiu iu khin logic 0 cng RD). Khi c tn hiu iu khin mc logic 1 chn RC1 th led hng n v s c m v thanh no c ni vi mc 0 s sng (tn hiu iu khin logic 0 cng RD).2.3.1.3 Khi iu khin trung tmiu khin cc khi khc thng qua phm mm iu khin: xut mc logic 0 hay 1 ra cc cng RB, RC, RD v nhn tn hiu logic t cng REKhi iu khin trung tm gm cc khi nh: Khi vi iu khin, khi to xung giao ng, khi reset.2.3.1.3.1 Khi reset.Hnh 2.6. S khi resetKhi RESET c tc dng a vi iu khin v trng thi ban u. Khi nt Reset c n in p +5V t ngun c ni vo chn Reset ca vi

vcc

iu khin c chy thng xung t lc ny in p ti chn vi iu khin thay i t ngt v 0, vi iu khin nhn bit c s thay i ny v khi ng li trng thi ban u cho h thng.2.3.1.3.2 Khi to xung giao ng.XTAL2XTAL1T2PIC16F877A

20MHz=C133pF:C 133pF

GNDHnh 2.7 S nguyn l khi to xung dao ng y l b dao ng thch anh c tc dng to xung nhp vi tn s 20MHz cho vi iu khin hot ng. Hai u ny c ni vo 2 chn XTAL1 v XTAL2 ca vi iu khin.2.3.1.3.3 Khi vi iu khin.MCLR/VPP/THV l401 RB7/PGD

RAO/ANo nu351 RB6/PGC

RA1/AN1GT3a| RB5

RA2/AN2/VREFw37] RB4

RA3/AN3/VREF+ ~5~i| RB3/PGM

RA4/TOCKI T3 RB2

RA5/AN4/SSQT13 RB 1

REO/RD/AN5 [rm RBO/INT

RE1 /WR/AN6 [H321 VDD

RE2/CS/AN7 [;PIC1 6F877~3 vss

VDD QT301 RD7/PSP7

vss 2mRD6/PSP6

OSC1 /CLKIN [UHI RD5/PSP5

OSC2/CLKOUT [T27] RD4/PSP4

RCO/1 OSI/T1 CKIm RC7/RX/DT

RC1/T1OSO/CCP2msl RC6/TX/CK

RC2/CCP1 T713 RC5/SDO

RC3/SCK/SCL m;m RC4/SDI/SDA

RDO/PSPO Tm RD3/PSP3

RD1/PSP1i21 RD2/PSP2

Hnh 2.8. S chn PIC6F877A Cc n tn hiu c icu khicn thng qua cng RB, Lcd 7 thanh c iu khin bng cng RD v RC ca PIC 16F877A.+ Khi nt bm c ni vo cc chn 9,10, 11 (REO,RE 1 ,RE2)+Khi dao ng ni vo chn 13 14(OSCl ,OSC2).+Khi ngun ni vo chn 11,12 v 31, 32. Vcc vo chn 11 v32.GND vo chn 12 v 31.+ Khi Reset ni vo chn 1 (MCLR).2.3.1.4 Khi ngun.UIvcc

GND

Hnh 2.9. S nguyn khi nguny l mch dng to ra ngun in p chun +5V. S dng IC7805.u vo l in p xoay chiu sau khi c bin i qua my bin th, a vo b Diod cu cho ra dng in mt chiu( lc ny in p nm trong khong t 7->10V). Sau khi i qua IC n p 7805 s to ra ngun in p chun +5V cung cp cho mch.IC n p 7805: u vo > 7V u ra 5V, 500 mA. Mch n p: cn cho vi iu khin v nu ngun cho vi iu khin khng n nh th s treo vi iu khin, khng chy ng hoc reset lin tc thm ch l cht vi iu khin.2.3.2 Nguyn l hot ng.Khi n nt Start h thng s hot ng theo thi gian mc inh hoc thi gian t.Thi im u tin n xanh r tri nhnh 1 v n nhnh 2 s sng.Thi im th 2 n xanh i thng v n nhnh 2 sng.Thi im th 3 n vng nhnh 1 v n nhnh 2 sng.Thi im th 4 n nhnh 1 v n xanh r tri nhnh 2 sng.Thi im th 5 n nhnh 1 v n xanh i thng nhnh 2 sng. Thi im th 6 n nhnh 1 v n vng nhnh 2 sng.ng thi trn cc led s hin th thi gian m ngc dn xung 00 theo thi gian tr l 1 s. Sau h thng s lp li trng thi hot ng t thi im u tin.Nu n nt Reset h thng s tr v trng thi ch' ban u.2.4 So' thut ton iu khin h thng n giao thng.2.4.1. Chng trnh chnh.

Chng trnh chnh

Bt u chng trnh chnh s kim tra phm bm :Neu kt=0 khng thay i thi gian hot ng v chng trnh s chy theo thi gian mc nh t sn+ n xanh r tri sng lOs,+n xanh i thngsng17s.+n vng sng 3s.+ n sng 30s).Neu bin kt=l c ngha l thay i thi gian hot ng ca n.+ n xanh r tri sng (Tt/3)(s).+n xanh i thngsngTt-(Tt/3+3)(s).+n vng sng 3s.+ n sng Tt(s).Chy vo chng trnh ngt sau ls th thi gian s gim xung 1 v xut tn hiu iu khin ra cc n. Chng trnh hin th s hin th thi gian m ngc ra cc LED 7 on.2.4.2. Cho'ng trnh ngt(^^begincount=0time=t3

count=0

Gim time xung 1 n v (time--)FT

time=t3(^END^)Hnh 2.11 .S thut ton iu khin chng trnh ngt

B mn k thut my tnhnmnhcHthngnhng

B mn k thut my tnhnmnhcHthngnhng

B mn k thut my tnhnmnhcHthngnhng

GVHD Th.s. Nguyn Vn HuyTrang 36

GVHD Th.s. Nguyn Vn HuyTrang 37

2.4.4 Chong trnh hin th

Xut tn hiu iu khin n ra cng RB:output_b(den[d])

Hnh 2.13 .S thut ton iu khin chng trnh hin tht lai bin d

2.4.5 Chng trnh set (hin th thi gian ci t cho h thng)

Ll=(time/ 1)% 10. L2=(time/ 10) % 10.

(^END^)Hnh 2.14 .S thut ton iu khin chng trnh set2.5 La chn lnh kin.2.5.1 B iu khin 8 bit Pic 16F877A.2.5.1.1. Tng quan v pic.a. PIC L G ?PIC l vit tt ca Programable Intelligent Computer, c th tm dch lmy tnh thng minh kh trnhdo hng Genenral Instrument t tn cho vi iu khin u tin ca h: PIC1650 c thit k dng lm cc thit b ngoi vi cho vi iu khin CP1600. Vi iu khin ny sau c nghin cu pht trin thm v t' hnh thnh nn dng vi iu khin PIC ngy nay.b. Ti sao li dng PIC m khng phi l cc loi vi iu khin khc.Hin nay trn th trng c rt nhiu h vi iu khin nh 8051, Motorola 68HC, AVR, ARM,...Ngoi h 8051 c hng dn mt cch cn bn mi trng i hc, bn thn ngi vit chn h vi iu khin PIC m rng vn kin thc v pht trin cc ng dng trn cng c ny v cc nguyn nhn sau: H vi iu khin ny c th tm mua d dng ti th trng Vit Nam. Gi thnh khng qu t. C y cc tnh nng ca mt vi iu khin khi hot ng c lp. L mt s b sung rt tt v kin thc cng nh v ng dng cho h vi iu khin mang tnh truyn thng: h vi iu khin 8051. S lng ngi s dng h vi iu khin PIC. Hin nay ti Vit Nam cng nh trn th gii, h vi iu khin ny c s dng kh rng ri. iu ny to nhiu thun li trong qu trnh tm hiu v pht trin cc ng dng nh: s lng ti liu, s lng cc ng dng m c pht trin thnh cng, d dng trao i, hc tp, d dng tm c s ch dn khi gp kh khn,...S h tr ca nh sn xut v trnh bin dch, cc cng c lp trnh, np chng trnh t n gin n phc tp,...Cc tnh nng a dng ca vi iu khin PIC, v cc tnh nng ny khng ngng c pht trin.

Hnh 2.15. nh thc t PIC16F877A

M c LR/VP P/THV rrV...' RB7/PGD

RAO/ANO [En RB6/RGC

RA 1 /AN 1 l~5~5 RB5

RA2/AN2/VREF \ZLg RB4

RA3/AN3/VREF+ fs~l RB3/PGM

RA4/TOCKI [~i~35] RB2

RA5/AN4/SS \zL15 RB1

REO/RD/AN5 [HI RBO/INT

RE 1 /WR/AN6 r~32| VDD

RE2/CS/AN7 [70m vss

VDD [TT301 RD7/PSP7

vss [H11 RD6/PSP6

OSC1 /CLKIN [Im RD5/PSP5

OSC2/CLKOUT E13 RD4/PSP4

RCO/1 OSI/T1 CKI QIm RC7/RX/DT

RC1/T1 OSO/CCP2 En RC6/TX/CK

RC2/CCP1 [T241 RC5/SDO

RC3/SCK/SCL [n;n RC4/SDI/SDA

RDO/PSPO [22| RD3/PSP3

RD1/PSR1 [5013 RD2/PSP2

Hnh 2.16. S chn ca PIC16F877A

2.5.1.2.2. Cc thng s ca PIC 16F877A.2.5.1.2 Gii thiu v PIC 16F877A. 2.5.1.2.1.S chn.

y l vi iu khin thuc h PIC16Fxxx vi tp lnh gm 35 lnh c di Mbit.Mi lnh u c thc thi trong mt chu k xung clock.Tc hot ng ti a cho php l 20 MHz vi mt chu k lnh l 200ns.B nh chng trnh 8Kxl4 bit, b nh d liu 368x8 byte RAM v b nh d liu EEPROM vi dung lng 256x8 byte.S PORT I/O l 5 vi 33 pin I/O.Cc c tnh ngoi vi bao gmcc khi chc nng sau:

+ TimerO: b m 8 bit vi b chia tn s 8 bit.+Timer 1: b m 16 bit vi b chia tn s, c th thc hinchcnngm da vo xung clock ngoi vi ngay khi vi iu khinhotng ch sleep.+ Timer2: b m 8 bit vi b chia tn s, b postcaler.Hai b Capture/so snh/iu ch rng xung.Cc chun giao tip ni tip SSP (Synchronous Serial Port), SPI v I2C.+Chun giao tip ni tip SART vi 9 bit a ch.+Cng giao tip song song PSP (Parallel Slave Port) vi ccchniu khin RD, WR, cs bn ngoi.Cc c tnh Analog: 8 knh chuyn i ADC 10 bit.Bn cnh l mt vi c tnh khc ca vi iu khin nh:+ B nh flash vi kh nng ghi xa c 100.000 ln.+ B nh EEPROM vi kh nng ghi xa c 1.000.000 ln.+ D liu b nh EEPROM c th lu tr trn 40 nm.Kh nng t np chng trnh vi s iu khin ca phn mm. Np c chng trnh ngay trn mch in ICSP (In Circuit Serial Programming) thng qua 2 chn.Watchdog Timer vi b dao ng trong.Chc nng bo mt m chng trnh.Ch Sleep.C th hot ng vi nhiu dng Oscillator khc nhau.2.5.1.2.3. Cng xut nhp (I/O port).Cng xut nhp (I/O port) chnh l phng tin m vi iu khin dng tng tc vi th gii bn ngoi. S tng tc ny rt a dng v thng qua qu trnh tng tc , chc nng ca vi iu khin c th hin mt cch r rng.Mt cng xut nhp ca vi iu khin bao gm nhiu chn (I/O pin), ty theo cch b tr v chc nng ca vi iu khin m s lng cng xut nhp v s lng chn trong mi cng c th khc nhau.Bn cnh , do vi iu khin c tch hp sn bn trong cc c tnh giao tip ngoi vi nn bn cnh chc nng l cng xut nhp thng thng, mt s chn xut nhp cn c thm cc chc nng khc th hin s tc ng ca cc c tnh ngoi vi nu trn i vi th gii bn ngoi. Chc nng ca tng chn xut nhp trong mi cng hon ton c th c xc lp v iu khin c thng qua cc thanh ghi SFR lin quan n chn xut nhp .Vi iu khin PIC16F877A c 5 cng xut nhp, bao gm PORTA, PORTB, PORTC, PORTD v PORTE.Cu trc v chc nng ca tng cng xut nhp s c cp c th trong phn sau. PORTA :PORTA(RPA) bao gm 6 I/o pin. y l cc chn hai chiu (bidirectional pin), ngha l c th xut v nhp c.Chc nng I/O ny c iu khin bi thanh ghi TRISA (a ch 85h). Mun xc lp chc nng ca mt chn trong PORTA l input, ta set bit iu khin tng ng vi chn trong thanh ghi TRISA v ngc li, mun xc lp chc nng ca mt chn trong PORTA l output, ta clear bit iu khin tng ng vi chn trong thanh ghi TRISA.Thao tc ny hon ton tng t i vi cc PORT v cc thanh ghi iu khin tng ng TRIS (i vi PORTA l TRISA, i vi PORTB l TRISB, i vi PORTC l TRISC, i vi PORTD l TRISD vi vi PORTE l TRISE).Cc thanh ghi SFR lin quan n PORTA bao gm: PORTA (a ch 05h) : cha gi tr cc pin trong PORTA. TRIS A (a ch 85h): iu khin xut nhp. CMCON (a ch 9Ch): thanh ghi iu khin b so snh. CVRCON (a ch 9Dh) : thanh ghi iu khin b so snh in p. ADCON1 (a ch 9Fh) : thanh ghi iu khin b ADC. PORTBPORTB (RPB) gm 8 pin I/o. Thanh ghi iu khin xut nhp tng ng l TRISB. Bn cnh mt s chn ca PORTB cn c s dng trong qu trnh np chng trnh cho vi iu khin vi cc ch np khc nhau.PORTB cn lin quan n ngt ngoi vi v b TimerO. PORTB cn c tch hp chc nng in tr ko ln c iu khin bi chng trnh. Cc thanh ghi SFR lin quan n PORTB bao gm: PORTB (a ch 06h,106h) : cha gi tr cc pin trong PORTB TRISB (a ch 86h,186h) : iu khin xut nhp OPTTON REG (a ch 81h,181h) : iu khin ngt ngoi vi v b TimerO.*PORTCPORTC (RPC) gm 8 pin I/o. Thanh ghi iu khin xut nhp tng ng l TRISC. Bn cnh PORTC cn cha cc chn chc nng ca b so snh, b Timerl, b PWM v cc chun giao tip ni tip I2C, SPI, SSP, USART.Cc thanh ghi iu khin lin quan n PORTC: PORTC (a ch 07h): cha gi tr cc pin trong PORTC TRISC (a ch 87h): iu khin xut nhp.*PORTDPORTD (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 (Parallel Slave Port).Cc thanh ghi lin quan n PORTD bao gm: Thanh ghi PORTD: cha gi tr cc pin trong PORTD.+Thanh ghi TRISD : iu khin xut nhp.+Thanh ghi TRISE : iu khin xut nhp PORTE v chun giaotip PSP. PORTEPORTE (RPE) gm 3 chn I/o. Thanh ghi iu khin xutnhptngng l TRISE. Cc chn ca PORTE c ng vo analog.BncnhPORTE cn l cc chn iu khin ca chun giao tip PSP.+Cc thanh ghi lin quan n PORTE bao gm: PORTE : chagi tr cc chn trong PORTE. TRISE: iu khin xut nhp v xc lp cc thng s cho chun giao tip PSP.+ ADCON1 : thanh ghi iu khin khi ADC.2.5.1.2.4. Timer. TIMER 0.y l mt trong ba b m hoc b nh thi ca vi iu khin PIC16F877A.TimerO l b m 8 bit c kt ni vi b chia tn s (prescaler) 8 bit. Cu trc ca TimerO cho php ta la chn xung clock tc ng v cnh tch cc ca xung clock.Ngt TimerO s xut hin khi TimerO b trn. Bit TMROIE (INTCON) l bit iu khin ca TimerO. TMR0IE=1 cho php ngt TimerO tc ng, TMR0IF= 0 khng cho php ngt TimerO tc ng.S khi ca TimerO nh sau.

Hnh 2.17. S khi ca timerO.Mun TimerO hot ng ch Timer ta clear bit TOSC (OPTION_REG), khi gi tr thanh ghi TMRO s tng theo tng chu k xung ng h (tn s vo TimerO bng % tan so oscillator). Khi gi tr thanh ghi TMRO t FFh tr v OOh, ngt TimerO s xut hin.Thanh ghi TMRO cho php ghi v xa c gip ta n nh thi im ngt TimerO xut hin mt cch linh ng.Mun TimerO hot ng ch counter ta set bit TOSC (OPTION_REG). Khi xung tc ng ln b m c ly t' chnRA4/T0CK1. Bit TOSE (OPTION_REG) cho php la chn cnh tc ng vo bt m. Cnh tc ng s l cnh ln nu TC)SE=0 v cnh tc ng s l cnh xung nu TOSE=l.Khi thanh ghi TMRO b trn, bit TMR0IF (INTCON) s c set. y chnh l c ngt ca TimerO. C ngt ny phi c xa bng chng trnh trc khi b m bt u thc hin li qu trnh m. Ngt TimerO khng th nh thc vi iu khin t' ch sleep. B chia tn s (prescaler) c chia s gia TimerO v WDT (Watchdog Timer). iu c ngha l nu prescaler c s dng cho TimerO th WDT s khng c c h tr ca prescaler v ngc li. Prescaler c iu khin bi thanh ghi OPTION REG. Bit PSA (OPTION_REG) xc nh i tng tc ng ca prescaler. Cc bit PS2:PS0 (OPTTON_REG) xc nh t s chia tn s ca prescaler. Xem li thanh ghi OPTION REG xc nh li mt cch chi tit v cc bit iu khin trn. Cc lnh tc ng ln gi tr thanh ghi TMRO s xa ch hot ng ca prescaler.Khi i tng tc ng l TimerO, tc ng ln gi tr thanh ghi TMRO s xa prescaler nhng khng lm thay i i tng tc ng ca prescaler.Khi i tng tc ng l WDT, lnh CLRWDT s xa prescaler, ng thi prescaler s ngng tc v h tr cho WDT. Cc thanh ghi iu khin lin quan n TimerO bao gm: TMRO (a ch Olh, lOlh): cha gi tr m ca TimerO.INTCON (a ch OBh, 8Bh, lOBh, 18Bh): cho php ngt hot ng (GIE v PEIE). OPTION REG (a ch 81h, 181h): iu khin prescaler.*TIMER 1.Timerl l b nh thi 16 bit, gi tr ca Timerl s c lu trong hai thanh ghi (TMR1H:TMR1L). C' ngt ca Timer 1 l bit TMR1IF (PIR1). Bit iu khin ca Timerl s l TMR1IE (PIE).Tng t nh TimerO, Timerl cng c hai ch hot ng: ch nh thi (timer) vi xung kch l xung clock ca oscillator (tn s ca timer bng Va tn s ca oscillator) v ch m (counter) vi xung kch l xung phn nh cc s kin cn m ly t bn ngoi thng qua chn RCO/TIOSO/TICKI (cnh tc ng l cnh ln).

Vic la chn xung tc ng (tng ng vi vic la chn ch hot ng l timer hay counter) c iu khin bi bit TMR1CS (T1C0N).So' khi ca Timerl:Set - lag bi! TMR1IF on Ove-rfowSynchronizedtrTMRtClock npuiTMR1LTMR10NOn/OffT1SYNC.- : TSC :