ghep noi may tinh (1)

8/8/2019 Ghep Noi May Tinh (1)

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KHOA IN-IN T LP TBD TRONG CN&GTVT-K13

I. KHO ST TN HIU VO - RA LIN QUAN BI TON1. Tn hiu analog:

Tn hiu analog (tng t) l loi tn hiu c cc gi tr bin lin tc theo thi gian, th d tn hiu thoi analog.Mt dng in hnh ca tn hiu analog l sng hnh sine, cth hin di dng:

S(t) = Asin (t + ) Trong : A l bin tn hiu, l tn s gc ( = 2f, f l tns), l pha ca tn hiu.

Nu tn hiu l tp hp ca nhiu tn s th ngoi cc tham strn y cn c mt tham s khc, l di tn ca tn hiu.

2. Tn hiu xung: Tn hiu xung: tn hiu xung l loi tn hiu c cc gi tr bin l hm ri rc ca thi gian. in hnh ca tn hiu xung ltn hiu xung ly mu tn hiu analog da vo nh l ly mu.

3. Tn hiu s:

Hnh: (a) H thng v tn hiu lin tc, (b) h thng v tn hiu ri rc

GHP NI MY TNHThit k mch thu nhn s liu Analog 2 knh

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Tn hiu s cng l loi tn hiu c cc gi tr bin l hm rirc ca thi gian nh tn hiu xung. Tuy nhin, khc vi tn hiuxung ch bin ca cc xung bng 0 hoc 1, mt khc tp

hp ca mt nhm xung i din cho mt ch s, hoc mt kt no . Mi mt xung c gi l mt bit. Mt vi loi tnhiu s in hnh nh: tn hiu 2 mc (0 v 1), cn c tn l tnhiu xung nh phn hay tn hiu xung n cc; v tn hiu bamc (-1, 0 v +1), cn c gi l tn hiu xung tam phn haytn hiu xung lng cc.Tn hiu s l tn hiu c ly mu v lng t ha. Ly mu l qu trnh bimt tn hiu tng t thnh mt tn hiu ri rc theo thang thi gian. nh l lmu (Shannon-Nyquist) ni rng mun khi phc mt tn hiu bng tn gc li

tc theo thi gian th bng thng ca tn hiu ban u phi c gii hn v tn sly mu phi ln hn hai ln bng thng ca tn hiu ban u.Lng t ha l qu trnh bin mt tn hiu c gi tr lin tc thnh tn hiu cgi tr ri rc Nhng tn hiu trong qu trnh c th c phn chia thnh tn hiu lin tc vtn hiu ri rc. Mi quan h gia tn hiu vo v tn hiu ra trong h thngc m t bng m hnh ton hc. H thng lin tc thng c m t bnnhng phng trnh vi phn thng, v c s dng trong l thuyt iu khituyn tnh. Nhng h thng ri rc thng c m t bng phng trnh sai

phn. H thng v tn hiu ri rc thng c s dng trong l thuyt iukhin s.Trong h thng iu khin s, ngi ta thng s dng b bin i lin tc-s(analogue-to-digital converter, hoc vit tt l b A/D, A/D Converter) bin imt tn hiu lin tc y(t) sang tn hiu s y(k). Tng t tn hiu ri rc u(k)trong b iu khin s i qua b bin i s-lin tc (digital-to-analogueconverter, hoc vit tt l b D/A, D/A Converter) s c bin i thnh tnhiu lin tc u(t).

4. Cc tham s ca tn hiu: Mc in tng i:

Trong :Px l cng sut tn hiu (mW) ti im cn xc nh mc inP0 l cng sut tn hiu ti im tham kho (mW). Mc in tuyt i:


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L(dB)m= 0 dBm khi cng sut ti im x bng 1 mWL(dBm) > 0 khi cng sut tn hiu ti im x ln hn 1 mWL(dBm) < 0 khi cng sut tn hiu ti im x b hn 1 mW.

T s tn hiu trn nhiu

trong :Ps, Vs, Is tng ng l cng sut, in p v dng in tn hiuPn, Vn, In tng ng l cng sut, in p v dng in nhiu

II. THIT K H THNG:

1. Phn tch u bi:- Tn hiu vo l tn hiu analog, mc tn hiu l 0-1V (theo yu cu u

bi), ngoi ratn hiu analog c th l tn hiu 1 chiu, xoay chiu, nhit , mthanh, p sut hoc m.

- Mch thit k yu cu cch li hon ton, chnh xc 1,5%.- Tc ly mu: 1kSps

Ly mu l qu trnh bin mt tn hiu tng t thnh mt tn hiu ri rc thethang thi gian. nh l ly mu (Shannon-Nyquist) ni rng mun khi phcmt tn hiu bng tn gc lin tc theo thi gian th bng thng ca tn hiu banu phi c gii hn v tn s ly mu phi ln hn hai ln bng thng ca thiu ban u.Tc ly mu s quyt nh c bao nhiu mu c ly trong mt giy. Nutc ly mu theo bi l 1kSps s tng ng vi 1000 mu/1s (khng ph thuc s bit) cho ta bit thi gian trch mu mi knh l 100s.

2. Nguyn l mch:Mch thu thp d liu analog c s dng trong cc thit b o lng v iukhin s bin i cc tn hiu analog thnh tn hiu s, n l mch ni ghpgia phn analog vi phn s v my tnh. Trong cc thit b o lng v iukhin s n gin, mch thu thp d liu analog thc hin lun chc nng xl, hin th v iu khin tip theo, cn trong cc h thng phc tp hn, cc thiu tng t sau khi c bin i thnh s liu v c x l s b


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mch thu thp d liu s c chuyn vo my tnh hoc thit b s khc ttc x l.

3. La chn phng n thit k:Phng n thit k phn cng: Nhm chng ti trnh by mch thu thp d lianalog 2 knh s dng b vi iu khin n chp 89C51 c th ni ghp vimy tnh qua cng s liu song song 8 bit v cng ni tip.Vi yu cu ca bi ton cho vi cc ch tiu ca h thng Ta la chn MCUv thit b chuyn i sao cho m bo c yu cu u ra nhng ph hpnguyn tc hn ch ti a s lng v loi linh kin ngoi..

a, Phng php phn cng:

Trong mch ta la chn thit k phn cng nh sau:- Thit k b nh:Chn 89C51 (U1) l b iu khin trung tm ca mch.Bn trong 89C51 tchhp sn 4 KB ROM (thuc loi Flash memory) v 128 byte RAM. Trong ROM dng cha chng trnh iu khin v RAM cha d liu. B nhny l kh nh nhng vn p ng c cc yu cu iu khin. Tuy nhin khing dng i hi chng trnh ln hoc d liu nhiu th b nh ni khng ng c. Khi 8951 cho php m rng thm b nh bn ngoi, c th gnthm ti a 64 KB ROM v 64 KB RAM [1,2].Trong thc t khi thit k b nh, ngi ta thng cn c vo nhu cu v linhkin c sn (hoc thng dng) thit k. h thng tng qut, a nng, chnh b nh cn thit k phi linh hot, cho php cm nhiu loi IC nh cdung lng khc nhau trn mt cm, khng phn bit ROM v RAM.Trn th trng hin nay, i vi IC ROM c cc loi thng dng 8KB, 16 KBv 32 KB, i vi RAM l 8 KB v 32 KB [3]. Cc loi ny c u c 28 chnv c s kh ging nhau nn c th cm trn cng mt c.T thc t trn, b nh c thit k vi 3 cm IC nh, c th cm c IC nh Cu hnh b nh trn c thc hin bng mt mch gii m b nh v mt bJumper chn cu hnh.B nh ny c bo v bng mt mch pht hin mt in. Ngay ti thi iin th cung cp va tt xung (trc khi CPU ngng hot ng), mch ny pht hin v kho b nh li, khng cho CPU truy xut na ( trnh trnghp CPU ghi nhm vo b nh trong lc qu do mt in). Sau dng it pin backup s tip tc lu gi d liu trong b nh cho n khi c in tr li.89C51 cung cp 32 ng vo/ra lp trnh c (port P0, P1, P2 v P3). Tuynhin khi m rng b nh ngoi, 16 ng ca port P0 v P2 s dng cho bus


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Hot ng ratio-metrically hoc vi 5 VDC hoc m rng tng t in p iu chnh

Khng i hi hiu chnh im gia hoc full-scale(gi ng kch thc thc s)

8-channel b a cng c cc a ch logicDi vo 0V ti 5V vi b cung cp nng lng n l

5VCc u vo tho mn in p mc ch nh TTL

kn tiu chun hoc kiu bao gi 28-pin DIPBao gi chuyn ch chip kiu c 28-pinADC0808 tng ng vi MM74C949ADC0809 tng ng vi MM74C949-1 Nhng c tnh ch cht: phn gii 8 BitsTng s li khng hiu chnh 12 LSB v 1 LSB Ngun cung cp n l 5 VDC Nng lng thp 15 mWThi gian chuyn i 100 s

- 74LS737 cng ra s liu song song 8bit;- 74LS93 b m.

- MAX232 cng trao i s liu ni tip:My tnh c thit k theo chun RS232 (c qui nh nm 1960) ,chun ny c qui nh trc khi xut hin h logic TTL (ra i nm1968 )nn mc in p ca n khng tng thch vi TTL:Qui nh ca chun RS232: space(logic 0) c tr s t +3 n +25v mark(logic 1) c tr s t -3 n -25v Min gia -3v n +3 v khng hp l Dng in ngn mch khng c vt qu 500mAV vy ta phi c mt mch li ng dy chuyn i tn hiu giRS232 v TTL, thit b c s dng l MAX232, DS275,

Bn cnh cn c bn phm s HEXA (KPI), cc linh kin bn dn, gic ktni, b dao ng thch anh, mn hnh tinh th lng v cc cng tc ngun

b, Phng php phn mm gii quyt bi ton:Trn phn cng thit k, cn phi xy dng mt phn mm iu khin. Phmm ny hot ng nh mt h iu hnh, c chc nng download chntrnh ngi dng (user program) v iu khin vic thc hin chng trnh .


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Ngoi ra cn phi cung cp cc tin ch cn thit khc. Phn mm c cc tnnng mnh sau y:- Son tho v bin dch chng trnh ngi dng.

- Download chng trnh bin dch xung h thng.- Thc hin chng trnh download (lin tc).- Thc hin tng lnh chng trnh.- Thc hin tng khi chng trnh.- Hin th tt c cc thng tin: gi tr cc thanh ghi, nh ni, nh ngoi,khi chy tng bc (tng lnh/ khi). Cho php thay i ni dung thanh ghhoc nh.- Hin th ni dung b nh.- T PC c th reset (mm) c h thng d ang chy bt c chng trn

no.- C th t ch t ng chy user program mi khi bt in (khi s dMPC iu khin h thng thc t).- Cung cp cc hm/chng trnh con tin ch khc,

Phn mm c thit k gm c hai phn: Phn chy trn my tnh PC (cvit bng ngn ng Visual Basic) v phn chy trn h thng MPC(c vit bng ngn ng Assembler ca AT89C51). Hai phn ny phi bt tay nhau rtcht ch bo m khng c bt k li no xy ra.Phn mm ca mch thu thp d liu ny c th vit trn ngn ng C hocAssembler (m ng), chng ti trnh by chng trnh m ng.

III. THIT K CHI TIT PHN CNG:

1. S khi:


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S ghp ni tng qut


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2. gii thch nguyn l hot ngca tng khi:

- Mch thu thp tn hiu:

Hnh: Tn hiu analog vo qua cng (gic) J1

Tn hiu vo l tn hiu analog, mc tn hiu l 0-1V (theo yu cu u bi),ngoi ratn hiu analog c th l tn hiu 1 chiu, xoay chiu, nhit , m thanh, p suthoc mtn hiu qua b bin i tng t s ADC0809 (U3) v c ni ticng PO ca 89C51, ADC0809 lm vic cn phi t in p chun Uref =+5v n chn REF+ v ni t chn REF-, ng thi phi a xung nhp ti

chn CLK ca n. Xung nhp cho ADC0809 c ly t chn ALE (30) ca89C51 ri c chia 2 bi b m 74LS93 (U5), nn nu tn s thch anh ca89C51 l 12MHz th xung trn u ra ALE l 2MHz v xung nhp caADC0809 l 1MHz. Cc s liu trch mu ca 2 knh analog c lu gi bnh RAM trong ca 89C51 v c th lp trnh cho 89C51 x l cc s liu theo tnh cht ca tng loi tn hiu tng t v theo mt s thut ton x l stn hiu n gin ri hin th chng ln LCD hoc gi ti my tnh hay thit bs khc qua cng ra s liu song song hoc cng ni tip. Vic chuyn s liuqua cng song song U2 n my tnh c th c thc hin theo phng phphi p hoc dng ngt nh cc tn hiu bo s liu ra sn sng DR do


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89C51 to ra trn chn cng P3.5 v tn hiu bo nhn xong s liu ACK domy tnh a ti chn cng INT0 (12) ca 89C51 . nhn 1 byte s liu tcng ra s liu song song U2, my tnh hoc thit b s khc phi a tn

hiu /RP ti chn OC ca 74LS373 iu khin m cng U2 cho s liu nchng.

- Ghp ni my tnh v thit b ngoi:

Hnh: cng ni tip vi my tnh hoc thit b s khc qua gic J2

Cng ra s liu song song 8 bit 74LS373 (U2) c ni ti cng PO ca 89C51

Ni ghp cng song song vi my tnh hoc thit b s khc c thc hin quagic J2, ni ghp cng ni tip vi my tnh hoc thit b s khc c thc hiqua gic J3. Cc tn hiu analog (tn hiu tng t) c a vo mch qua giJ1 , 2 knh tn hiu analog n t u ra ca cc mch bin i, tn hiu tng

c gi tr 1V c a vo x l.

- Khi nhp d liu:


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Hnh: Bn phm s nhp d liu ngoi

Bn phm s HEXA (KPI) c ni n cng P2 ca 89C51. Bn phm KPI vLCD c s dng lm phng tin giao tip gia ngi vi my thit lp lm vic v hin th cc s liu cn thit.Bn phm s KP1 c16 phm, c t chc thnh 4 hng v 4 ct, nn mch raca n c 4 tn hiu ct v 4 tn hiu hang

- Hot ng ca b iu khin trung tm:

Hnh: Vi mch 89C51 (U1) l b iu khin trung tm ca mch


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Trong mch thu thp d liu analog ny, b vi iu khin 89C51 c thit l lm vic trong ch khng dng b nh ngoi, v th chn /EA (31) c89C51 c ni vi ngun +5v. ch ny, tt c 4 cng P0 n P3 c

89C51 u c s dng lm cng vo ra v chng c ni ti cc thit bngoi vi nh ni trn.Mch RESET cng ca 89C51 c thc hin trn cc in tr R1 , R2, t

in C3 v phm n RESET. Khi bt ngun, ban u t C3 coi nh b ngnmch nn chn RESET (9) ca 89C51 c gi mc cao (>1,8v) trongkhong thi gian cho 89C51 RESET mch ni b, ngha l n khi to gitr ban u cho cc thanh ghi chc nng c bit SFR v t b m chntrnh PC tr n a ch 00h ca b nh chng trnh EEPROM bn trong89C51. Do t C3 c np vi hng s thi gian t = c3.R1 = 0,1ms nn in

trn chn RESET (9) ca 89C51 gim dn, khi in p trn chn 9 nh hn 0,5vth qu trnh RESET kt thc, CPU ca 89C51 gi lnh cha a ch 00h c b nh chng trnh vo n thc hin, 89C51 bt u hot ng theo chtrnh cha EEPROM bn trong n. Phm n RESET l lm cho mch chyli t u ging nh khi bt ngun m khng cn ngt, bt ngun. Khi n phRESET, t C3 b ngn mch v phng in qua in tr R2, do khi nh phmRESET trong mch din ra qu trnh ging nh khi bt ngun.

Cng P2 ca 89C51 c s dng qut bn phm nhm pht hin phmc n v c m phm vo 89C51, cc chn cng P2.0 n P2.3 (21 24) qut cc ct, cn cc chn cng P2.4 n P2.7 (25 28) qut cc hng c bn phm KP1. Vic qut bn phm v c m ca phm n c thc hin bmt chng trnh con ca phn mm EEPROM ca 89C51.

Cng P0 ca 89C51 va l cng vo nhn s liu ca ADC0809, va lcng ra np s liu cho LCD v cng song song U2, mi thi im, phmm iu khin s quyt nh P0 ch phc v mt trong cc mch ngoi vi trDo P0 c s dng lm cng ra nn cn treo cc chn ca n ln mc cao bng in tr bng R3 (8x10k) c mt u chung c ni vi ngun +5v.

Cng P1 ca 89C51 c s dng chn mch ngoi vi ni ti P0 v iu khin b hin th tinh th lng LCD v b bin i tng t sADC0809.Chn cng P1.5 (6) ca 89C51 l tn hiu ra LPA tch cc mc caoc a ti u vo IE ca 74LS373 cho php n cht s liu do 89C51 ra trn cng P0 gi ti my tnh hoc thit b s khc. Chn cng P1.6 (7ca 89C51 l tn hiu ra ELCD tch cc mc cao c a ti u vo EN cLCD cho php LCD nhn cc s liu trn cng P0 do 89C51 a ra hith trn LCD . Chn cng P1.7 (8) ca 89C51 l tn hiu ra RLCD tch cc mccao c a ti u vo RS ca LCD xa s liu ang c hin th trLCD. Cc chn cng P1.0, P1.1, P1.2 (1, 2, 3) ca 89C51 l cc tn hiu raSA0, SA1, SA2 c a ti cc chn A0, A1 , A2 ca ADC0809 chn hatrong tm knh analog trn u vo ca ADC0809 c trch mu. Chn cng


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P1.3 (4) ca 89C51 l tn hiu ra STAR tch cc theo sn xung c a tcc u vo START v ALE ca ADC0809 cht cc tn hiu chn knhanalog v bt u qu trnh trch mu tn hiu tng t ca knh analog

chn. Sau xn xung ca tn hiu STAR, ADC0809 s iu khin tn hiu EOC ca n xung mc thp bo bt u qu trnh trch muvi tc trchmu 1kSps, sau khong 100s qu trnh trch mu kt thc, ADC0809 iukhin tn hiu EOC ln mc cao bo s liu trn u ra ca n sn sntn hiu ny c a ti chn cng INT1 (13) ca 89C51. Sau khi nhn tn hiu EOC mc cao, 89C51 s a ra tn hiu OUT mc cao chn cnP1.5 (6) cho php ADC0809 m cng s liu ra ca n, s liu ny 89C51 c vo cng P0.

Nh vy, ti mi thi im, ADC0809 ch cho php trch mu mt knh tn

hiu analog do 89C51 chn v bng cch thay i cc tn hiu ra SA0, SA2,SA3 t gi tr00h n 01h, 89C51 iu khin ADC0809 ln lt trch mu c2 knh tn hiu tng t. Thi gian trch mu ca mi knh l 100s (theo ra), do nu 2 knh analog u lm vic th chu k trch mu nh nht cmi knh analog l khong 200s, tng ng tn s trch mu 400 Hz.

- Cng trao i s liu ni tip:

Hnh: Cng trao i s liu ni tip MAX232

Cng trao i s liu ni tip MAX232 (U4) ni n cng P3 ca 89C51


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Cc cng s liu ni tip v song song l chuyn s liu cho my tnh hocthit b s khc, ngoi ra cng ni tip c th nhn cc lnh iu khin ca mtnh

Vic trao i s liu ni tip vi my tnh c thc hin theo chuRS232 qua vi mch MAX232 v gic J3. y, cc chn ra ca J3 c thik m bo c th ni thng cc dy tng ng n gic 9 chn ca cCOM1 my tnh.

IV. THIT K CHI TIT PHN MM:

D liu c truyn qua li gia PC v MPC thng qua cng COM1 (hoCOM2). Tc truyn d liu c chn l 9600bps, parity chn, bo truyn rt t li vi tc tng i nhanh.Trong phm vi ca bi bo co chng ti xin gii thiu phn m u cchng trnh chnh c lnh gi chng trnh con iu khin vic trch muknh tn hiu tng t ri ct s liu vo b nh RAM ca 89C51 thnh 2 mring bit cho 2 knh, mi mng di 5 s liu. Phn m u ca chng trnm ng thng phi khai bo cc bin v cng s liu c s dng tronchng trnh, sau l khi to im bt u ca chng trnh khi RESET vcc vector ngt bng cc ch dn ORG v cc lnh nhy n chng trnh chnv cc chng trnh con phc v ngt. Chng trnh chnh bt u t a ch30h ca b nh chng trnh EEPROM. on u ca chng trnh chnh lkhi to nh ngn xp, thit lp cc ngt c s dng v mc u tin cho cngt . Vic trch mu v to cc mng s liu ca 2 knh analog RAMtrong c thc hin bi chng trnh con CONV do chng trnh chnh g bng lnh ACALL.Di y l on m u ca chng trnh chnh v chng trnh con CONV.

;* * * * ** * * * * * * * ** **.* ** ** *** * ** * *Chng trnh iu khin ADC0809 trch mu 2 knh analog v ct s liuvo RAM trong;

;* * * * * * * *** * * * ** ** ** * ** ** * ** ** **

; Khai bo tn v a ch ca cc bin byte

BUFFEQU30h; a ch u vng m ct s liu RAM trong

TOP-SPEQU6fh; nh ngn xp khi khi ng

; Khai bo gi tr ca cc hng s liu tc thi


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LENGEQU5; di mi mng s liu ca mt knh

NUMBEQU 2; s knh analog cn trch mu; Khai bo tn v a ch ca cc bin bt

SA0 BITP1.0; AO chn cng analog ca ADC0809

SA1 BITP1.1; Ai chn cng analog ca ADC0809

SA2BITP1.2; A2 chn cng analog ca ADC0809

STARTBIT P1.3 ; Sn xung ca START bt u trch mu

OUT BIT P1.4 ; OUT="1" , M m ra ca ADC0809 n cng P0

LATCH BIT P1.5 ; LATCH="1" , Cht s liu ca cng P0 vo U2

E-LCD BIT P1.6 ; E_LCD="1" , Cht s liu ca cng P0 vo LCD

C-LCDBIT P1.7 ; C_LCD="1" , Xa b hin th LCD

EOC BIT P3.3 ; EOC="1" , Bo kt thc trch mu (l ngt INT1)

; M chng trnh bt u t y. Khi to cc vector ngt INT0 v cng nitip

ORG 00h ; a ch bt u chng trnh khi RESET

AJMP MAIN ; Nhy n im bt u chng trnh chnh

ORG 03h ; a ch vector ngt ngoi INT0

AJMP S_INTO ; Nhy n chng trnh con x l ngt INT0

ORG 23h ; a ch vector ngt cng ni tip.

AJMP S_PORT ; Nhy n chng trnh con x l ngt cng ni tip

;* ** * * * * * * * *** * * *** * * * * * * * *** * *


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; Bt u chng trnh chnh;

;* * * * *** * * ** * * * * * * * *** * *** * * * * *ORG 30h ; im nhp ca chng trnh chnh

MAIN:MOV SP,#TOP_SP ; Np nh ngn xp l a ch TOP_ SP RAM

MOV IE,#92h ; Cho php cc ngt INT0 v cng ni tip

MOV IP,#02h : Ngt INT0 mc u tin cao

MOV TCON,#01h ; t INT0 tc ng theo sn xung

MOV P2,#08h ; Xa cc bt cng P2 bng 0, ring START= 1

REL0:ACALL CONV ; Gi chng trnh con trch mu 2 knh analog

;........

; Tip theo l cc lnh x l v trao i s liu

;......

NOP

AJMP REL0 ; Nhy v RELO trch mu ly s liu

;......

; Ht chng trnh chnh, bt u cc chng trnh con

;** * * *** * ** * * **** * * * * *** **** ** ** * * * *** *

; CONV: Chng trnh con trch mu tn hiu ca 2 knh analog v cts liu thnh 2 mng;

; Cho 2 knh, mi mng di 5 byte bt u t a ch BUFF RAMtrong ca 89C51;


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; S dng cc thanh ghi: R0, R6, R7, B v thanh cha A

;****** ******* ************ *** * ********* ** *

CONV:MOV R6,LENG ; Dng R6 lm con m ch s mng s liu

MOV B,BUFF ; B cha a ch ct s liu ca knh 0 (mng 0)

MOV R7,#0 ; R7 gi a ch chn knh analog, t knh 0

CONI: MOV R0,B ; R0 l con tr ct s liu vo RAM trong

CON2: CLR SA0 ; Xo SA0 = 0CLR SA1 ; Xo SA1 = 0

CLR SA2 ; Xo SA2 = 0

MOV A,R7 ; Np a ch chn knh analog vo A

ORL P1,A ; Gi a ch chn knh analog n ADC0809

NOP ; Gi chm a ch n nh

CLR START ; Sn xung ca START kch bt u trch mu

JB EOC,$ ; i ADC0809 h EOC="0" bo bt u trch mu

SETB START ; Tr START v mc cao: START="1

JNB EOC,$ ; i EOC="1" bo kt thc trch mu

SETB OUT ; OUT = 1, m mch ra ADC0809 ti cng P0

NOP ; Gi chm cho s liu n nh trn BUS

MOV @R0,P0 ; Ct s liu trch mu vo nh tr bi R0

MOV A,R0 ; Gi gi tr ca R0 vo A:(A)="(R0)

ADD A,#LENG ; (A)="(A)+LENG" , a ch ct s liu ca knh sau


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18/19


MOV R0,A ; R0 tr n nh ct s liu ca knh tip theo

INCR7 ; Tng a ch chn knh analog n knh tip theoCJNER7,#NUMB, CON2 ; (R7)


19/19


GHP NI MY TNHThi k h h h li A l 2 k h

19

ghep noi may tinh (1)

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