Đồ án Đo khoảng cách sóng siêu âm hiển thị led 7 thanh

TRNG H K THUT CNG NGH TP HCM N MN HC: DO KHONG CCH

LI M U Cm bin trong ting anh gi l sensor xut pht t ch sense tc l cm nhn. T ngnxa ngi tin s nh vo cc gic quan xc gic cm nhn, tm hiu c im cath gii t nhin v hc cch s dng nhng hiu bit nhm mc ch khai thc thgii xung quanh phc v cho cuc sng ca h. Trong thi i pht trin ca khoa hc v k thut ngy nay con ngi khng ch da vocc c quan xc gic ca c th km ph th gii. cc chc nng xc gic nhn bitcc vt th hin tng xy ra trong thin nhin c tng cng nh cc pht trin dng cdung lng v phn tch m ta gi l cm bin. Cm bin c nh ngha nh cc thit b dung bin i cc ddaij lng vt l v cci lng khng in cn o thnh cc i lng in c th o c( nh dng in,inth,in dung , tr khng). N l thnh phn quan trng nht trong cc thit b o haytrong cc h thng iu khin t ng . c th ni: nguyn l hot ng ca mt cm bin,trong hiu trng hp thc t cng chnh l nguyn l ca php o hay ca phng phpiu khin t dng.

t lu cm bin c s dng nh nhng b phn cm nhn v pht hin, nhngch t vi chc nm tr li y chng mi th hin r vai tr quan trng trong cc hotng ca con ngi. Nh nhng thnh tu mi ca khoa hc v cng ngh trong lnh vcvt liu, thit b in t v tin hc, cc cm bin c gim thiu kch thc, ci thintnh nng v ngy cng m rng phm vi ng dng. gi y khng c mt lnh vc nom khng s dng cc cm biin. chng c mt trong cc h thng t ng phc tp,ngi my, kim tra cht lng sn phm, ti kim nng lng, chng nhim mitrng. Cm bin cng c s dng rng ri trong lnh vc giao thng vn ti, hang tiudung, bo qun thc phm, t, tr chi in t..

Mt trong cc ng ng rt dng ri v ph bin l cm bin v tr v dch chuyn. Vvic kim tra v tr v dch chuyn dng vai tr raats quan trng i vi hot ng canhiu my mc,cng c. Hn na, mt s i lng vt l c th o c thng qua vicxc nh s dch chuyn ca mt vt chu tc ng ca i lng vt l . C nhiu phng php xc nh v tr v dch chuyn. trong phm vi mn hc, chngta c th thit k c mt mch in t n gin o khoang cch, s dng cm binsiu m. lm mch ny cn thit k c 3 phn chnh : b phn cm bin - b phn xl - b phn hin th.

LP 09HDT1SVTH: BI CNG TUN MSSV: 09B1010058

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PH LC.LI M U...................................................................................................1PH LC..........................................................................................................2BNG NHN XT CA GIO VIN HNG DN..................................3BNG NHN XT CA GIO VIN PHN BIN.....................................4PHN II : L THUYT THIT K................................................................5

I.S KHI..............................................................................................5II. KHI CM BIN SIU M SRF 05 :...................................................5

1. Gii thiu cm bin siu m SRF05 :....................................................52.Thng s k thut :..................................................................................53.Ch hoat ng :.................................................................................6

3.1Ch 1 :..........................................................................................63.2Ch 2 :..........................................................................................7

4.Chc nng cc chn :..............................................................................85. Nguyn tc hot ng ca SRF05:........................................................86. Tnh ton v xc nh khong cch :.....................................................8

III.KHI IU KHIN ATMEGA8..........................................................111.S chn ATMEGA8 :......................................................................112.T chc ca ATMega8 ni ring, AVR ni chung..............................12

2.1 B nh d liu...............................................................................122.2 Vng Nh......................................................................................132.3RAM tnh, ni (internal SRAM)....................................................132.4RAM ngoi (external SRAM)........................................................142.5EEPROM (Electrically Ereasable Programmable ROM)...............14

3.Cu trc bn trong ca ATMEGA8.....................................................14IV. KHI HIN TH...................................................................................15

1.Chc Nng chn LCD..........................................................................152.S khi LCD...................................................................................16

2.1Cc thanh ghi..................................................................................162.2C bo bn BF................................................................................162.3B m a ch AC : (Address Counter)........................................172.4Vng RAM hin th DDRAM : (Display Data RAM)...................172.5Vng ROM cha k t CGROM: Character Generator ROM........182.6 Vng RAM cha k t ha CGRAM: (Character Generator RAM)...................................................................................................19

PHN III: NI DUNG THI CNG..............................................................20I.S NGUYN L...............................................................................20II. CODE LP TRNH CHOVDK:.............................................................21

PHN IV : U NHC IM V TLTK..................................................25I.U IM :...............................................................................................25II.NHC IM :......................................................................................25III.TI LIU THAM KHO:.....................................................................25


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BNG NHN XT CA GIO VIN HNG DNGio vin hng dn : NGUYN TH NGC ANHH v tn sinh vin : Bi Cng Tun

Lp : 09HDT1Mssv : 09B1010058

Tn ti: THIT K V THI CNG MCH DO KHONG CCH ..................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................im nh gi : ...................Xp loi : ................................................

TP H Ch Minh, ngy 28 thng 11 nm 2010

Gio vin hng dn( K tn v ghi r h tn)


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BNG NHN XT CA GIO VIN PHN BINGio vin phn bin : H v tn sinh vin : BI CNG TUN

Lp : 09HDT1Mssv : 09B100058

Tn ti: THIT K V THI CNG MCH O KHONG CCH..................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................im nh gi : ...................Xp loi : ................................................

TP H Ch Minh, ngy thng nm 2010

Gio vin phn bin( K tn v ghi r h tn)


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PHN II : L THUYT THIT K

I. S KHI

II. KHI CM BIN SIU M SRF 05 : 1. Gii thiu cm bin siu m SRF05 :

SRF05 l mt bc pht trin t SRF04 , oc thit k lm tng tnh linh hot, tng phm vi hot dng v gim chi ph. Do ,SRF05 hon ton tng thch vi SRF04. Khong cch c tng ln t 3 mt n 4 mt. Mt ch hot ng mi (chn chnch ni t ) cho php SRF05 s dng mt chn duy nht cho c kch hot v phn hi,do tit kim chn cho b iu khin ca bn. Khi chn ch c ngt kt ni,SRF05 hot ng vi cc chn kch hot v chn phn hi ring bit. chn hi tip, gingnh l SRF04. SRF05 thit lp sn mt thi gian tr nh trc khi xung phn hi mangli iu khin chm hn chng hn nh b iu khin thi gian c bn Stamps v Picaxe thc hin cc xung lnh.

HNH: cm bin siu m SRF05.

2. Thng s k thut :


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in p 5VDng thp 4mATn s 40KHzPhm vi hot ng 1cm - 4cmLoi 1 chn cho triger/echo

hoc 2 chn tng thch SRF04 u vo kch khi 10uS min, mc xung TTLXung va p Mc tn hiu dng, b rng i xng

43x20x17 (mm)iu khin t ng Khng nh kch c hot ng, tu x l, hot ng nhanhTgian hot ng Thi gian hi p, a tn hiu iu khin

Khi cm bin siu m SRF05

Khi iu khin ATMEGA8

Khi hin th LCD


3. Ch hoat ng :

3.1 Ch 1 : Ch ny s dng chn kch hot v chn phn hi ring bit, v l ch n ginnht s dng. Tt c cc chng trinh mu cho SRF04 s lm vic vi SRF05 ch ny. s dng ch ny, ch vic ngt kt ni chn mode - SRF05 c mt in tr nipull up chn ny.


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3.2 Ch 2 : Ch ny s dng mt chn duy nht cho c tn hiu kch hot v hi tip, v cthit k lu cc gi tr trn chn ln b iu khin nhng. s dng ch ny, chn mode ni vi mass. Tn hiu hi tip s xut hin trn cngmt chn vi tn hiu kch hot. SRF05 s khng tng dng phn hi cho n 700uS saukhi kt thc cc tn hiu kch hot. Bn c thi gian kch hot pin xoay quanh v lmcho n tr thnh mt u vo v c pulse o m ca bn sn sng. Lnh PULSINc tm ra v c dng ph bin hin nay iu khin t ng.


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4. Chc nng cc chn : - Echo Output : chn u ra tn hiu phn hi v t cm bin. - Triger Output : chn u vo kch hot - Mode : chn ch ( khng c kt ni ch mt) - b nm chn bn kia : 5 c ng nhn l "programming pins" ch c s dng mtln duy nht trong qu trnh sn xut lp trnh cho b nh Flash trn chip PIC16F630. Cc chn chng trnh ca PIC16F630 cng c s dng cho cc chc nng khc trnSRF05, nn chc chn rng bn khng kt ni bt c ci g vi cc chn, hoc bn s lmgin on hot ng m-un

5. Nguyn tc hot ng ca SRF05:

T gin iu khin ta thy : - SRF05 hot ng ta cn cp mt xung mc cao c rng t nht l 10uS trn

chn TRI - sau SRF05 s pht ra mt chu k 8 khi tn hiu siu m tn s 40KHz v tng

dng tn hiu phn hi ca n ln mc cao (hoc ng tn hiu kch hot ch 2 ) . sau n ch phn hi, v ngay sau khi pht hin mt vt th n s gimdng phn hi xung. do dng phn hi s l mt xung c rng t l vikhong cch ti vt th. Bng cch o xung , ta hon ton c th tnh ton khongcch theo n v inch / cm hay bt c g khc. Nu khng pht hin vt th thSRF05 s ko dng phn hi xuc mc thp sau 30mS .

- SRF04 cung cp mt xung phn hi t ln vi khong cch. Nu o rng caxung bi uS, sau chia cho 58 s cho ta khong cch tnh bng cm, hoc chia cho148 s cho khong cch atinhs bng inches: uS/58=cm hoc uS/148=inches.

- SRF05 c th c kch hot nhanh chng vi mi 50mS, hay 20 ln / s. Bn nn i 50ms trc xung kch hot k tip, ngay c khi SRF05 pht hin vt th gnv xung phn hi ngn hn. iu ny m bo rng siu m beep tt hn vkhng lm sai lch tn hiu phn hi trong ln o tip theo c bit SRF05 ch c th nhn xung trn chn TRI ti a 20 Hz,cho nn vic kch xungtrn chn TRI phi ph hp th SRF05 mi hot ng chnh xc.

6. Tnh ton v xc nh khong cch : Sng siu m c truyn i trong khng kh vi vn tc 343 m/s. Nu mt cm binpht ra sng siu m v thu v cc sng phn x ng thi, o c khong thi gian tlc pht ra ti lc thu v, th my tnh c th xc nh c qung ng m sng dichuyn trong khng gian. Qung ng di chuyn ca sng = 2 ln khong cch t cmbin ti chng ngi vt theo hng pht ca sng siu m. khong cch t cm bin ti chng ngi vt s c tnh theo nguyn l TOF


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d = ( Time Of Flight )

Trong : d- khong cch cn o v- vn tc sng siu m trong mi trng truyn sng t: thi gian t lc sng c pht i n lc sng c ghi nhn li

5- sai s v hiu chnh cm bin : a- sai s : hin tng c cho(crosstalk) ca cm bin.


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Hin tng forecasting :


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III. KHI IU KHIN ATMEGA8.

1. S chn ATMEGA8 :

Bn c th thy chip ny gm 28 chn, trng c cc chn c ghi l PB0(chn 14),PB1(chn 15),,PB7(chn 10), l cc chn ca PORTB. PORT l khi nim ch ccng xut nhp. Trong AVR, PORT c th giao tip theo 2 hng (bi directional), c thdng xut hoc nhn thng tin, mi PORT c 8 chn. Chip Atmega8 c 3 PORT c tntng ng l PORTB, PORTC v PORTD (mt s chip AVR khc c 4 hoc 6 PORT).PORT c coi l ca ng then cht ca vi iu khin. Trong AVR, mi PORT lin quan n 3 thanh ghi (8 bits) c tn tng ng l DDRx,PINx, v PORTx vi x l tn ca PORT, mi bit trong thanh ghi tng ng vi mi chnca PORT. Trong trng hp ca Atmega8 x l B, C hoc D. V d chng ta quan tmn PORTB th 3 thanh ghi tng ng c tn l DDRB, PINB v PORTB, trong 2 thanhghi PORTB v PINB c ni trc tip vi cc chn ca PORTB, DDRB l thanh ghi iukhin hng ( Input hoc Output). Vit gi tr 1 vo mt bit trong thanh ghi DDRB thchn tng ng ca PORTB s l chn xut (Output), ngc li gi tr 0 xc lp chntng ng l ng nhp. Sau khi vit gi tr iu khin vo DDRB, vic truy xut PORTBc thc hin thng qua 2 thanh ghi PINB v PORTB. Quay li vi 2 dng code ca chng ta, dng u: LDI R16, 0xFF, vi LDI LoaDImmediately, dng lnh c ngha l load gi tr 0xFF vo thanh ghi R16, R16 l tn 1thanh ghi trong b nh ca AVR, 0xFF l 1 hng s c dng thp lc phn, k hiu 0xni ln iu , bn cng c th dng k hiu khc l $ ch 1 s thp lc phn, v d&FF, v 0xFF=255(thp phn)=0B11111111 (nh phn). Nh th sau dng u thanh ghiR16 c gi tr l 11111111 (nh phn). Dng th 2: OUT DDRB, R16 ngha l xut gitr t thanh ghi R16 ra thanh ghi DDRB, tm li sau 2 dng trn gi tr DDRB nh sau:

1 1 1 1 1 1 1 1 C th bn s hi ti sao chng khng s dng 1 dng duy nht l LDI DDRB, 0xFFhay OUT DDRB, 0xFF, chng ta khng th v lnh LDI ch cho php thc hin trn ccthanh ghi R16,R31 v lnh OUT khng thc hin c vi cc hng s. V v DDRB=11111111 nn trong trng hp ny tt c cc chn ca PORTB snsng cho vic xut d liu. Lc ny thanh ghi PINB khng c tc dng, thanh ghi PORTBs l thanh ghi xut, ghi gi tr vo thanh ghi ny s tc ng n cc chn ca PORTB.1.


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2. T chc ca ATMega8 ni ring, AVR ni chung.C cu trc Harvard, trong ng truyn cho b nh d liu (data memory bus) vng truyn cho b nh chng trnh (program memory bus) c tch ring. Datamemory bus ch c 8 bit v c kt ni vi hu ht cc thit b ngoi vi, vi register file.Trong khi program memory bus c rng 16 bits v ch phc v cho instructionregisters. Hnh 1 m t cu trc b nh ca AVR. B nh chng trnh (Program memory): L b nh Flash lp trnh c, trong ccchip AVR c (nh AT90S1200 hay AT90S2313) b nh chng trnh ch gm 1 phn lApplication Flash Section nhng trong cc chip AVR mi chng ta c thm phn BootFlash setion. Boot section s c kho st trong cc phn sau, trong bi ny khi ni v bnh chng trnh, chng ta t hiu l Application section. Thc cht, application sectionbao gm 2 phn: phn cha cc instruction (m lnh cho hot ng ca chip) v phn chacc vector ngt (interrupt vectors). Cc vector ngt nm phn u ca application section(t a ch 0x0000) v di n bao nhiu ty thuc vo loi chip. Phn cha instructionnm lin sau , chng trnh vit cho chip phi c load vo phn ny.

B nh d liu (data memory): y l phn cha cc thanh ghi quan trng nht cachip, vic lp trnh cho chip phn ln l truy cp b nh ny. B nh d liu trn cc chipAVR c ln khc nhau ty theo mi chip, tuy nhin v c bn phn b nh ny cchia thnh 5 phn.

2.1 B nh d liu.Bao gm 32 thanh ghi c tn gi l register file (RF), hay General Purpose Rgegister

GPR, hoc n gin l cc Thanh ghi. Tt c cc thanh ghi ny u l cc thanh ghi 8 bitsnh trong hnh 2.

Hnh 2. Thanh ghi 8 bits. Tt c cc chip trong h AVR u bao gm 32 thanh ghi Register File c a ch tuyti t 0x0000 n 0x001F. Mi thanh ghi c th cha gi tr dng t 0 n 255 hoc ccgi tr c du t -128 n 127 hoc m ASCII ca mt k t no Cc thanh ghi nyc t tn theo th t l R0 n R31. Chng c chia thnh 2 phn, phn 1 bao gmcc thanh ghi t R0 n R15 v phn 2 l cc thanh ghi R16 n R31. Cc thanh ghi ny ccc c im sau:c truy cp trc tip trong cc instruction.Cc ton t, php ton thc hin trn cc thanh ghi ny ch cn 1 chu k xung clock.Register File c kt ni trc tip vi b x l trung tm CPU ca chip.Chng l ngun cha cc s hng trong cc php ton v cng l ch cha kt qu tr lica php ton.


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2.2 Vng NhVng nh I/O l ca ng giao tip gia CPU v thit b ngoi vi. Tt c cc thanh

ghi iu khin, trng thica thit b ngoi vi u nm y. Xem li v d trong bi1, trong ti c cp v vic iu khin cc PORT ca AVR, mi PORT lin quann 3 thanh ghi DDRx, PORTx v PINx, tt c 3 thanh ghi ny u nm trong vngnh I/O. Xa hn, nu mun truy xut cc thit b ngoi vi khc nh Timer, chuyn iAnalog/Digital, giao tip USARTu thc hin thng qua vic iu khin cc thanhghi trong vng nh ny. Vng nh I/O c th c truy cp nh SRAM hay nh cc thanh ghi I/O. Nu sdng instruction truy xut SRAM truy xut vng nh ny th a ch ca chng ctnh t 0x0020 n 0x005F. Nhng nu truy xut nh cc thanh ghi I/O th a ch cachng c tnh t 0x0000 n 0x003F.

2.3 RAM tnh, ni (internal SRAM).L vng khng gian cho cha cc bin (tm thi hoc ton cc) trong lc thc thi

chng trnh, vng ny tng t cc thanh RAM trong my tnh nhng c dung lngkh nh (khong vi KB, ty thuc vo loi chip).


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2.4 RAM ngoi (external SRAM).Cc chip AVR cho php ngi s dng gn thm cc b nh ngoi cha bin, vngny thc cht ch tn ti khi no ngi s dng gn thm b nh ngoi vo chip

2.5 EEPROM (Electrically Ereasable Programmable ROM)l mt phn quan trng ca cc chip AVR mi, v l ROM nn b nh ny khng bxa ngay c khi khng cung cp ngun nui cho chip, rt thch hp cho cc ng dnglu tr d liu. Nh trong hnh 1, phn b nh EEPROM c tch ring v c a chtnh t 0x0000.

3. Cu trc bn trong ca ATMEGA8

Hnh . Cu trc bn trong ATmega 8.

ATmega c 32 thanh ghi trong Register File c kt ni trc tip vi ArithmeticLogic Unit -ALU (ALU cng c xem l CPU ca AVR) bng 2 line, v th ALU cth truy xut trc tip cng lc 2 thanh ghi RF ch trong 1 chu k xung clock. (vngc khoanh trn mu trong hnh 4).Cc instruction c cha trong b nh chng trnh Flash memory di dng ccthanh ghi 16 bit. B nh chng trnh c truy cp trong mi chu k xung clock v 1instruction cha trong program memory s c load vo trong instruction register,instruction register tc ng v la chn register file cng nh RAM cho ALU thc thi.Trong lc thc thi chng trnh, a ch ca dng lnh ang thc thi c quyt nh


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bi mt b m chng trnh PC (Program counter). chnh l cch thc hot ngca AVR. AVR c u im l hu ht cc instruction u c thc thi trong 1 chu k xungclock, v vy c th ngun clock ln nht cho AVR c th nh hn 1 s vi iu khinkhc nh PIC nhng thi gian thc thi vn nhanh hn

IV. KHI HIN TH.

1. Chc Nng chn LCD.S Chn Tn Chc Nng1 Vss Chn ni t cho LCD, khi thit k mch ta ni chn ny vi

GND ca mch iukhin

2 Vdd Chn cp ngun cho LCD, khi thit k mch ta ni chn ny viVCC=5V ca mchiu khin

3 Vee iu khin tung phn ca LCD4 RS Chn chn thanh ghi (Register select). Ni chn RS vi logic

0 (GND) hoc logic1 (VCC) chn thanh ghi.+ Logic 0: Bus DB0-DB7 s ni vi thanh ghi lnh IR caLCD ( ch ghi -write) hoc ni vi b m a ch ca LCD ( ch c -read)+ Logic 1: Bus DB0-DB7 s ni vi thanh ghi d liu DRbn trong LCD.

5 R/W Chn chn ch c/ghi (Read/Write). Ni chn R/W vilogic 0 LCD hotng ch ghi, hoc ni vi logic 1 LCD ch c

6 E Chn cho php (Enable). Sau khi cc tn hiu c t ln busDB0-DB7, cc lnh ch c chp nhn khi c 1 xung cho php ca chn E.+ ch ghi: D liu bus s c LCD chuyn vo(chpnhn) thanh ghi bn trong n khi pht hin mt xung (high-to-low transition) ca tnhiu chn E.+ ch c: D liu s c LCD xut ra DB0-DB7 khipht hin cnh ln (low-to-high transition) chn E v c LCD gi bus n khi nochn E xung mcthp.

7-14 BD0-BD7 Tm ng ca bus d liu dng trao i thng tin viMPU. C 2 ch sdng 8 ng bus ny : + Ch 8 bit : D liu c truyn trn c 8 ng, vi bitMSB l bit DB7.+ Ch 4 bit : D liu c truyn trn 4 ng t DB4 tiDB7, bit MSB l DB7


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Chi tit s dng 2 giao thc ny c cp phn sau

2. S khi LCD

Hinh: S khi ca LCD

2.1 Cc thanh ghiChp HD44780 c 2 thanh ghi quan trng.

- Thanh ghi IR: iu khin LCD. Ngui dng phi ra lnh thng qua ung bustn hiu, mi lnh uc nh cung cp qui nh r rang. Ngi dung ch vic cungcp a ch lnh bng cch np vo thanh ghi IR. Ngha l, khi ta np vo thanh ghiIR mt chui 8 bit, chp HD44780 s tra bng m

lnh ti a ch m IR cung cp v thc hin lnh - Thanh ghi DR dung cha d liu 8 bit ghi vao RAM DDRAM hoc CG

RAM. Hoc dung cha d liu t hai vng RAM gi ra MPU. Ngha l, khiMPU ghi thng tin vo DR, mch ni bn trong chp s t ng ghi thng tin nyvo DDRAM hoc CGRAM. Hoc khi thng tin v a ch c ghi vo IR, d liu a ch ny trong vng RAM ni caHD44780 s c chuyn ra DR truyncho MPU.

2.2 C bo bn BFHi thc hin cc hot ng bn trong chp, mch ni bn trong cn mt khongthi gian hon tt. Khi ang thc thi cc hot ng bn trong chip nh th,LCD b qua mi giao tip vi bn ngoi v bt c BF(thng qua chn DB7 khic thit lp RS=0, R/W=1) ln bo cho MPU bit n ang bn. D nhin, khi xong vic, n s t c BF li mc 0.


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2.3 B m a ch AC : (Address Counter)Nh trong s khi, thanh ghi IR khng trc tip kt ni vi vng RAM(DDRAM v CGRAM) m thng qua b m a ch AC. B m ny li ni vi 2 vng RAM theo kiur nhnh. Khi mt a chlnh c np vo thanh ghi IR, thng tin c ni trc tip cho 2 vng RAMnhng vic chn la vng RAM tng tc c bao hm trong m lnh. Sau khi ghi vo (c t) RAM, b m AC t ng tng ln (gim i) 1 n vv ni dung ca AC cxut ra cho MPU thng qua DB0-DB6 khi c thit lp RS=0 v R/W=1 (xembng tm tt RS - R/W).Lu : Thi gian cp nht AC khng c tnh vo thi gian thc thi lnh mc cp nht sau khi cBF ln mc cao (not busy), cho nn khi lp trnh hin th, bn phi delay mtkhong tADDkhong 4uS-5uS (ngay sau khi BF=1) trc khi np d liu mi. Xem thm hnh bn di.

2.4 Vng RAM hin th DDRAM : (Display Data RAM)y l vng RAM dng hin th, ngha l ng vi mt a ch ca RAM lmt k t trn mn hnh v khi bn ghi vo vng RAM ny mt m 8 bit, LCD s hin th ti v tr tngng trn mn hnh mt k tc m 8 bit m bn cung cp. Hnh sau y s trnh by r hn mi lin hny Vng RAM ny c 80x8 bit nh, ngha l cha c 80 k t m 8 bit. Nhng

vng RAM cn likhng dng cho hin th c th dng nh vng RAM a mc ch. Lu l truy cp vo DDRAM, ta phi cung cp a ch cho AC theo mHEX


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2.5 Vng ROM cha k t CGROM: Character Generator ROMVng ROM ny dng cha cc mu k t loi 5x8 hoc 5x10 im nh/k t,v nh a ch bng8 bit. Tuy nhin, n ch c 208 mu k t 5x8 v 32 mu k t kiu 5x10 (tngcng l 240 thay v 28= 256 mu k t). Ngi dng khng th thay i vng ROM ny.

Hnh 5 : Mi lin h gia a ch ca ROM v d liu to mu k t.


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2.6 Vng RAM cha k t ha CGRAM: (Character Generator RAM)

Nh trn bng m k t, nh sn xut dnh vng c a ch byte cao l 0000 ngi dng c th to cc mu k t ha ring. Tuy nhin dung lng vngny rt hn ch: Ta ch c th to 8 k t loi 5x8 im nh, hoc 4 k t loi5x10 im nh. ghi vo CGRAM, hy xem hnh 6 bn di

Hnh 6 : Mi lin h gia a ch ca CGRAM, d liu ca CGRAM, v m k t.


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PHN III: NI DUNG THI CNG

I. S NGUYN L

V C C

C 41 0 4

J 4

S R F 0 5

12345

V C C

M O S I

V C C

E S

R D

D B 6

J 1

L C D 1 6 x 2

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

U 1

A T M E G A 8

1

2

3

4

5

6

7

8

9

1 0

1 1

1 2

1 3

1 41 5

1 6

1 7

1 8

1 9

2 0

2 1

2 2

2 3

2 4

2 5

2 6

2 7

2 8R E S E T / P C 6

P D 0 / R X D

P D 1 / T X D

P D 2 / I N T 0

P D 3 / I N T 1

P D 4 / T 0 / X C K

V C C

G N D

P B 6 / T O S C 1 / X T A L 1

P B 7 / T O S C 2 / X T A L 2

P D 5 / T 1

P D 6 / A I N 0

P D 7 / A I N 1

P B 0 / I C P 1P B 1 / O C 1 A

P B 2 / O C 1 B / S S

P B 3 / O C 2 / M O S I

P B 4 / M I S O

P B 5 / S C K

A V C C

A R E F

G N D

A D C 0 / P C 0

A D C 1 / P C 1

A D C 2 / P C 2

A D C 3 / P C 3

S D A / A D C 4 / P C 4

S C L / A D C 5 / P C 5

R W

J 3

C O N 2

12

R e s e t

R e s e t

S C K

V C C

U 2

L M 7 8 0 5 C / T O

1 3I N O U T

C 31 0 u F

T r i g e r I n p u t

E c h o O u t p u t

D B 4

S C K

C 24 7 0 u F

G N D

C 51 0 4

D B 7

M I S O

T r i g e r I n p u t

D B 5M I S O

V C CE c h o O u t p u t

M O S I

J 2

C A P N A P

1234567891 0


20


II. CODE LP TRNH CHOVDK:

/*****************************************************This program was produced by theCodeWizardAVR V2.03.9 StandardAutomatic Program Generator Copyright 1998-2008 Pavel Haiduc, HP InfoTech s.r.l.http://www.hpinfotech.com

Project : Version : Date : 11/25/2010Author : Bui Cong TuanCompany : Comments:

Chip type : ATmega8Program type : ApplicationAVR Core Clock frequency: 4.000000 MHzMemory model : SmallExternal RAM size : 0Data Stack size : 256*****************************************************/

#include #include

#define Signal_Output PORTC.0 #define Signal_status DDRC.0 // 0 = In & 1 = Out#define Signal_Input PINC.0

// Alphanumeric LCD Module functions#asm .equ __lcd_port=0x12 ;PORTD#endasm#include

//Child programvoid lcd_putint(unsigned int so, unsigned char x, unsigned char y); //Display intergernumber void lcd_putnum(unsigned char So, unsigned char x, unsigned char y); //Display charnumberunsigned int read_from_sensor();

// Declare your global variables here


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unsigned int Distance; //Store distance value =Wide_of_pulse/58 cm;wide_of_pulse/148 Inch. 3-400 cmunsigned int Wide_of_pulse; volatile unsigned char TimerStatus;unsigned int TempI;unsigned char TempC;

interrupt [TIM0_OVF] void timer0_ovf_isr(void){// Reinitialize Timer 0 valueTCNT0=0x28;// Place your code hereTimerStatus=1;}

void main(void){// Declare your local variables herePORTB=0x00;DDRB=0x00;PORTC=0x00;DDRC=0xff;

PORTD=0x00;DDRD=0xFF;

TCCR0=0x01;TCNT0=0x28;

// Analog Comparator initialization// Analog Comparator: Off// Analog Comparator Input Capture by Timer/Counter 1: OffACSR=0x80;SFIOR=0x00;

// Global enable interrupts#asm("sei")

// LCD module initializationlcd_init(16);

//*** sensor initial *** Signal_status = 1; // out Signal_Output = 1; delay_ms(35); Signal_status = 0; // In Signal_Output = 0; delay_ms(10);

while (1)


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{ // Place your code here lcd_gotoxy(0,0); lcd_putsf("Distant measure");

//Wide_of_pulse = 0; //Reset counter Wide_of_pulse = read_from_sensor(); Distance = Wide_of_pulse/58; //cm lcd_putint(Distance,5,1); lcd_putsf("Cm"); delay_ms(1000); if (TempC


if (TimerStatus==1) { TimerStatus=0; wide_pulse++; } } Signal_status = 0; // Set Input Signal_Output = 0; #asm("cli") //Disable interupt return wide_pulse; } void lcd_putint(unsigned int so, unsigned char x, unsigned char y) //65535 { unsigned char N1=0; unsigned char N10=0; unsigned char N100=0; unsigned char N1K=0; unsigned char N10K=0; //#asm("wdr"); N10K = so/10000; N1K = (so - N10K*10000)/1000; N100 = (so - N10K*10000 - N1K*1000)/100; N10 = (so - N10K*10000 - N1K*1000 - N100*100)/10; N1 = (so - N10K*10000 - N1K*1000 - N100*100 - N10*10); lcd_gotoxy(x,y); lcd_putchar(N10K+48); lcd_putchar(N1K+48); lcd_putchar(N100+48); lcd_putchar(N10+48); lcd_putchar(N1+48); } void lcd_putnum(unsigned char So, unsigned char x, unsigned char y) { unsigned char Tram=0; unsigned char Chuc=0; unsigned char Donvi=0; //#asm("wdr"); Tram = So/100; Chuc = (So - Tram*100)/10; Donvi = (So - Tram*100 - Chuc*10); lcd_gotoxy(x,y); lcd_putchar(Tram+48); lcd_putchar(Chuc+48); lcd_putchar(Donvi+48); }


24


PHN IV : U NHC IM V TLTK.

I. U IM : - khong cch m cm bin c th pht hin ln ti 4m.- sng phn hi khng ph thuc vo mu sc,b mt ca vt th hay tnh cht phn x nhsang ca i tng. - tn hiu p ng ca cm bin analog l t l tuyn tnh vi khong cch. iu ny cbit l tng cho cc ng dng nh theo di cc mc vt cht, mc chuyn ng ca ditng.- mch in t n gin, x l tn hiu d rng.

II. NHC IM : - Cm bin siu m yu cu i tng c mt din tch b mt ti thiu (ph thuc votng loi cm bin)- sng phn hi m cm bin siu m nhn c c th chu nh hng ca sng m thanhtp m - cm bin siu m yu cu mt khong thi gian sau mi ln sng pht i sn sngnhn sng phn hi. Kt qu nhn chung chm hn cc cm bin khc - cm bin siu m c gii hn khong cch pht hin nh nht. - s thay i ca mi trng nh nhit (vn tc m thanh ph thuc vo nhit ),psut, s chuyn ng khng u ca khng kh, bi bn bay trong khng kh gy nhhng n kt qu o. Nhit ca b mt i tng lm nh hng n phm vi hot ng ca cm bin, lmmo dng sng ,lm cho khoang cch pht hin ngn li v kt qu khng chnh xc. - b mt phng phn hi nng lng ca sng siu m tt hn mt g gh,tuy nhin b mttrng phng li c i hi kht khe v v tr gc to thnh gia cm bin v mt phng itng.

III. TI LIU THAM KHO:www.datasheep.com www.ant7.com


25

LI M UPH LC.BNG NHN XT CA GIO VIN HNG DNBNG NHN XT CA GIO VIN PHN BINPHN II : L THUYT THIT KI. S KHIII. KHI CM BIN SIU M SRF 05 :1. Gii thiu cm bin siu m SRF05 :2. Thng s k thut :3. Ch hoat ng :3.1 Ch 1 :3.2 Ch 2 :

4. Chc nng cc chn :5. Nguyn tc hot ng ca SRF05:6. Tnh ton v xc nh khong cch :

III. KHI IU KHIN ATMEGA8.1. S chn ATMEGA8 :2. T chc ca ATMega8 ni ring, AVR ni chung.2.1 B nh d liu.2.2 Vng Nh2.3 RAM tnh, ni (internal SRAM).2.4 RAM ngoi (external SRAM).2.5 EEPROM (Electrically Ereasable Programmable ROM)

3. Cu trc bn trong ca ATMEGA8

IV. KHI HIN TH.1. Chc Nng chn LCD.2. S khi LCD2.1 Cc thanh ghi2.2 C bo bn BF2.3 B m a ch AC : (Address Counter)2.4 Vng RAM hin th DDRAM : (Display Data RAM)2.5 Vng ROM cha k t CGROM: Character Generator ROM2.6 Vng RAM cha k t ha CGRAM: (Character Generator RAM)

PHN III: NI DUNG THI CNGI. S NGUYN LII. CODE LP TRNH CHOVDK:

PHN IV : U NHC IM V TLTK.I. U IM :II. NHC IM :III. TI LIU THAM KHO:

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