Dung nhiu Led siu sang vi ngun nui DC thp

Rt vui khi thy vo xem...Dn nhp

Bn

T khi ngi ta ch ra c cac loai en Led chiu sang co hiu sut cao thi no a c ng dung rng rai trong cng ngh trang tri cho cac san phm, nh lam cac bang en quang cao, nh dung trong cac mach chi thi bng anh sang, nh lam en chiu sang cng cng, lam cac mach nhac quang rt hp dn, va lam ca man hinh co phn giai cao na... Vi cac u im cua Led hin co, Khng bit ri ngay mai, ngi ta con dung no cho vic gi na. Hay ch xem! Va qua ti nhn c mt in th, ni dung cu hoi co lin quan n cac Led siu sang dung trong cac may in thoai cm tay, th hoi nh sau:

Cho thy. Em tnh c tm c trang web phuclanshop, thc s n rt b ch. nhng vi ngi c t kin thc v in t nh em th tht l kh hiu ht. Tnh hnh l by gi em ang lm 1 ci mch LED cho bn phm t em v n hng mt ri. Ci em cn lm nh trong clip ny : http://www.youtube.com/watch?v=WFFHbcEVskI Cng khng cn cu k, em ch cn thit k 1 mch khong 45 con led nhy theo th t. bnh thng th mch ny khng phi l kh. Nhng ngun pin t ch c 3.7v v mch thit k yu cu phi nh cho gn vo bn trong t c. Theo em tm hiu th phi dng ic dn + led dn. Nhng em cha bit phi dng loi ic no c Nht To c. Mong thy gip . Cm n thy.

Trong ln nay mn y trong in th cua mt Ban oc vit cho ti, ti se trinh bay cach dung cac Led siu sang trong cac mach in chay mc ngun DC thp va vit m rng v cach s dung cac ic nng ap DC va cach tao cac mach Led nhay theo iu nhac. Mong bai vit c nhiu Ban vao xem.

Tim hiu mach chiu sang man hinh mau trong cac may in thoai di ng. Trc ht theo dong tin hoa, chung ta hay tim hiu cac mach chiu sang man hinh dung trong cac may in thoai di ng co man hinh en trng, nh may Nokia 6110, ri qua may Nokia 3310... Ri cung phai theo s tin hoa, khi cac may in thoai di ng bt u dung n cac loai man hinh mau thi mach chiu sang man hinh mau cung phai co nhiu thay i, luc nay ngi ta cn co cac Led trng, lai phai dung loai Led siu sang mi u manh va cung dung it s Led hn. Chung ta bit loai Led siu sang co mc rao ap n 3V, do o cac mach in chiu sang dung trong thi ky man hinh en trng khng con thich hp na, va ngi ta a nghia ra cac mach in khac, thich hp hn, o la cac mach nng ap, nng mc ap DC thp ln mc ap DC cao, iu quan trong na la loai mach nng ap nay phai co hiu sut cao, nu khng thi pin se rt mau ht. o chinh la vn ma chung ta se ban n sau y. 1. Mach chiu sang man hinh en trng cac may in thoai i cu

cac in thoai di ng i cu, man hinh thng la dang en trng, nn ngi ta co th dung cac Led mau chiu sang cac man hinh nay, y la loai Led co mc rao ap thp, thng t 1.8V n 2.2V, do vy vic kich sang cac Led nay vi mc ngun pin cua in thoai la 3.6V se rt n gian. Trong hinh ngi ta cho mc cac led theo dang song song, cac chn Anode cho ni vao ngun dng cua pin Ion Li+ (Mc ap danh inh la 3.6V). Cac chn Cathode nhn dong t chn C cua transistor npn. Trn chn E la in tr inh dong 15 ohm, trn chn B co in tr 2.2K dung han dong IB va dung in tr vai K trn chn B ni masse lam tng h s n inh nhit. Mun transistor cp dong lam sang cac Led chiu sang trn chn C, ngi ta cho CPU xut lnh BLight vi mc ap dng trn chn B cua cac transistor nay. Noi chung mach rt d hiu va rt d sa. 2. Mach chiu sang man hinh en trng may i DCT3.

Trong cac may in thoai i DCT3, nh may Nokia 3310, 8210...Tuy mach co cai tin so vi may Nokia 5110, 6110... nhng do may vn con dung dang man hinh en trng nn mach chiu sang v nguyn tc vn dung cac Led mau thng. Trong cac may nay, ngi ta dung IC cp dong cho cac Led chiu sang. Chung ta ve lai s mach in trn, Ban thy:

* Dong chay ra trn chn s 13 lam sang cac Led chiu sang ban phim. in tr R311 (10K) co tac dung inh dong. Lnh tt m cac Led chiu sang ban phim a vao trn chn 15. * Dong chay ra trn chn s 9 lam sang cac Led chiu sang man hinh. in tr R310 (12K) co tac dung inh dong. Lnh tt m cac Led chiu sang man hinh a vao trn chn 7. IC TA23A lam vic vi chn s 1 ni vao cc dng cua pin va cac chn s 4, 5, 10 va 11, 12, 17, 18 cho ni masse. Mc ap Enable trn chn s 2 dung tam tt ic TA23A, khi may i vao mode nghi. 3. Mach chiu sang man hinh mau trong i may DCT4 (may Nokia 7210).

Vi cac may in thoai di ng i DCT4, mt cai tin quan trong la may chuyn qua dung man hinh mau, vi man hinh mau, cac Led chiu sang phai u manh va nht la phai co mau trng. Do o ngi ta chuyn qua dung loai Led trng siu sang, c tinh cua loai Led nay la co rao ap cao, thng la 3V, do vy vi ngun pin co mc ap danh inh la 3.6V thi cac kiu mach chiu sang cua cac may i cu khng con phu hp na. Ngi ta phai giai quyt bng cac kiu mach t nng ap va nht la loai mach nay con phai co hiu sut cao tranh hao pin.

Trn y la s mach Led dung chiu sang man hinh mau dung trong may in thoai Nokia 7210, cung tng t trong cac may 6100, 3210, 3100, 6610, 6600...Chung ti chon kiu mach nay trinh bay la do mach dung ic chn t canh, thay vi dung chn bung, vic "ch bin" trn cac ic co chn t bung, vic han rap se kho khn hn. Tim hiu ic nng ap TK11851L.

Theo trang t liu cua nha san xut, chung ta bit: IC co 8 chn, Cng dung cua cac chn nh sau:

* Chn 1: Chn cp ngun. Ban cho ni chn nay vao cc dng cua pin, vi pin in thoai Ion Li+, mc ap trn cc dng cua pin thay i t 4.2V (luc pin nap y) va 3.2V, y la "mc cht", mc volt nay may se t tt ch Ban nap in lai cho pin. IC nay co th lam vic vi mc ngun trn chn s 1 la 2.7V n 6.5V. * Chn 2: Chn cho dong in chay ra t chn s 3 qua cun dy L chay tr vao va cho chay qua mt in tr nho 0.3 ohm ri chay ra trn chn s 1 v cc dng cua pin. Ngi ta dung in tr 0.3 ohm o dong, t o iu chinh lai hoat ng cua mach, nhm tranh hin tng ic bi qua dong. * Chn s 3: la chn C cua mt transistor khoa, s ong m nhanh cua transistor nay se cp dong in dang xung kich thich cun dy L, chung ta bit khi s tt m nhanh mt dong in chay qua mt cun dy L, trn cun dy L nay se phat sinh ra in ap ng co bin cao. Ngi ta se dung diode cho nn dong nap mc ap ng nay vao cac tu in co ma ap DC cao. * Chn s 4: Trn chn nay ngi ta cho inh mc ap nga ra bng mt diode zener, khi mc ap nga ra cao hn mc ap cua diode zener, diode nay se dn in va no se lam tt mach ong m cua transistor, trong IC a co diode zener dung xac inh mc ap nga ra khoang 14V, di nhin Ban co th dung diode zener ngoai chon inh lai mc ap nga ra theo ung y cua Ban. * Chn s 5: Trn chn nay co mt in tr dung o cng dong in chay qua cac Led chiu sang. No tao tac dung hi tip nghich dung gi cho cng dong in chay qua cac Led lun khng thay i, nh vy mc sang chiu trn man hinh mau khng bi anh hng do mc ap trn pin co thay i. * Chn s 6: cho ni masse. Dong in t chay vao IC qua chn nay. * Chn s 7: Ngi ta co th thay i tn s cua xung bng cach thay i tri s cua tu in Cx gn trn chn nay. Vi tu Cx la 68pF, tn s cuaq mach dao ng tao xung la 300KHz.

* Chn s 8: Chn nay dung nhn lnh ong m mach. Vi mc volt cao, transistor trong IC se ong mach va mach se hoat ng va khi chn nay mc volt thp, transistor ngng dn, mach se vao trang thai "ngu", trang thai sleep, ic n dong rt rt nho. Phn tich mach:

Hinh ve cho thy, chn Vin cho ni vao cc dng cua ngun pin, chn GND cho ni masse, ic se c cp in. Trn chn Cx Ban cho gn tu inh tn Cosc. Luc nay se co dong xung chay ra trn chn Ext, dong nay chay vao chn Is qua in tr o dong t bn trong ic. Dong xung kich thich cun cam L gn trn Ext, chn Is. Cun cam L se phat ra xung bin cao trn chn Ext, ngi ta dung mt diode Schocky co mc ap tn hao nho nn dong, cho dong nap vao tu Cout co mc ap DC cao. Dung mc ap nay, khoang 14V, cp dong cho cac Led siu sang trng. Dong chay qua cac Led cho chay qua mt in tr i dong ra ap va cho mc volt nay tra v mach hi tip nghich trn chn FB, dung ng hi tip nghich nay n inh dong chay qua cac Led, du mc volt DC trn chn Vin co thay i. Mt gi y: Qua phn trinh bay trn, chung ta thy mun co dong khoang 10mA cp cho cac Led trng siu sang, Ban co

th dung nguyn ly cua mach in trn. c im cua loai mach nay la co kich thc rt gon nho, va do mach dung ic co chn canh nn cung rt d han rap, toan mach co th gn gon trong cac thit bi "ti hon". Mach co th lam vic vi loai pin Ion Li+ co mc ngun danh inh 3.6V, do mach co hiu sut rt cao, trn 90%, nn khng hao pin. Cu hoi la i u mua c loai ic nay? Ti khng bit ch Nht Tao P7 - Q10 co ban cac linh kin nay hay khng. Nhng nu chi lam thc hanh hoc tp va chi lam mt vai b thi Ban co th tim mua cac may in thoai di ng h ra ly linh kin, loai may h nay co ban bn kia ng gn ch Nht Tao va gia ban cung thp. Nu co nhu cu Ban hay th xem.

Tim hiu cac IC nng ap DC thp ln mc DC cao co hiu sut cao:UTJ34063.

S chc nng cua IC cho thy, trong IC co mt mach dao ng dung tao ra xung ong m. Tn s xung tuy theo tri cua tu in gn trn chn TC, tn s dao ng t 100Hz n 100KHz. Xung ra cho tac ng vao chn Reset cua mt Flip Flop. Nga ra Q cua Flip Flop cho tac ng vao chn B cua hai transistor ghep phc hp. SE la chn E chung. SC la chn C cua

transistor cng sut. DRI la chn C cua transistor thuc. Trong IC co ngun in ap mu 1.25V cp cho tng so ap, in ap hi tip a vao tng so ap qua chn FB vao chn ao, nga ra cua tng so ap qua cng AND cho tac dung vao cng Set cua Flip Flop. Chn IPK dung gii han mc dong inh. IC lam vic vi chn GND cho ni masse va chn Vcc cho ni ngun DC. IC co th lam vic vi mc ngun vao Vin t 3V n 40V. Cu truc cua mach trong IC cho thy, ngi ta dung dong xung tao ra t mach dao ng cho kich thich cun cam L tao ra in ap ng co mc ap cao va dung diode Schocky nn dong cho nap dong xung vao tu nng ap. Khi mach dung nh mt mach giam ap DC thi dung cun cam nh mt kho cha in, kt hp vi diode ly dong nghich tng n inh ng ngun nga ra. Cach tng ap hay giam theo theo tin hiu dang xung cho hiu sut rt cao, trn 90%. Loai IC nay hin co rt nhiu va kha thng dung.

Di y la cac mach in ng dung in hinh:

Trong IC co mach dao ng tao ra tin hiu dang xung, tn s tin hiu nay ly theo tri cua tuc in Cx gn trn chn s 3. Tin hiu xung qua tng ao tac dung vao chn Reset cua Flip Flop, tin hiu dang xung vung cho ra trn chn Q cua Flip Flop dung ong m nhanh hai transistor Q1, Q2 ghep theo kiu phc hp. co dong xung kich thich cun cam L gn trn chn C cua transistor Q2, tc chn s 1 cua IC. Chn s 2 cua IC phai cho ni masse, va chn 8 cua IC cho ni ln ngun in dng qua in tr giam ap 150 ohm. Khi cun cam bi kich thich bi dong xung chay ra trn chn s 1, no se phat ra in ap ng co bin cao trn chn s 1, ngi ta dung diode Schottky co mc tn hao nho nn dong va cho dong nap vao mt tu hoa ln 220uF co mc ap DC cao, 28V vi kha nng cp dong cho tai la 200mA.

Dong in dang xung cho chay qua in tr o dong 0.22 ohm tao ra tin hiu a vao trn chn s 7 co tac dung han bin dong xung inh. in ap DC ly trn nga ra, trn tu 220uF, qua mach chia ap vi in tr 47K va 2.2K tao ra in ap hi tip nghich a vao IC trn chn 5 n mach so ap, cho so vi mc ap mu la 1.25V tao ra tac dung xac inh mc ap trn nga ra. Nh vy mun iu chinh mc ap nga ra Ban co th cho thay i tri cua in tr 2.2K. Mach bin i mc ap DC thp ln mc ap DC cao nay dung it linh kin ngoai, hiu sut lai rt cao, nn hin nay rt c a dung.

S nay cho thy mun co dong xung manh hn, Ban phai dung thm transistor ngoai. Luc nay chn 2 cho ni vao chn B cua transistor ngoai, in tr R2 co tac dung lam tng n inh nhit, chn C cua transistor ngoai ni vao chn s 1, tc cho ni vao chn C cua transistor Q2 trong IC, chn E cua transistor ngoai cho ni masse, vi mach nay kha nng cp dong cho tai se ln hn. Mt cai bin rt n gian tng kha nng cp dong cho tai.

S trn cho thy cach dung IC xung lam mach giam ap DC. Luc nay xung ly ra trn chn E cua hai transistor Q1, Q2. co mc ap DC ra n inh, cun cam L dung lam cun loc. Khi Q1, Q2 dn in, dong in cp cho tai se cho chay qua cun cam L, luc nay cun dy L va co tac dung n dong, va ng thi va tich tr in nng, khi Q1, Q2 tt, luc nay in nng tich tu trong cun cam L se hoan tra lai di dang in ap ng, du cua in ap ng se lam thng diode D, va dong in ng lai c cho nap vao tu C. Vi c ch nay, chung ta thy mach dung hai kho cha in n inh iu kin cp in cho tai, mt kho ap vi tu hoa ln C (470uF) va mt kho dong vi cun cam L (200uH). mach nay vi in tr ly tin hiu hi tip 3.6K va 1.2K, in ap ra se c gi n inh mc 5V, in ap vao co th thay i trong khoang 9V n 30V.

Noi thm cho ro:

Hinh ve trn giai thich vai tro dung lam kho cha in cua cun cam L va tu in C. Vi cun cam L khi co dong in I chay qua no se tich tr in nng di dang t trng trong cun dy va vi tu in C khi co in ap t ln tu no se tich in di dang in trng ct trong lp in mi. Mun n inh in nng chung ta co th dung cun cam n dong hay dung tu in n ap.

Trong mach nay ngi ta dung thm transistor ngoai Q3 tng kha nng cp dong cho cun cam L, va nh o tng c kha nng cp dong cho tai. Trong mach: R2 dung han dong chn B va R1 dung lam tng h s n inh nhit cho Q3. RB va RA la cu chia volt dung ly tin hiu cho chn hi tip FB, tri cua hai in tr nay se xac inh mc ap nga ra. Khi Q3 dn, cun cam L c nap in nng va khi Q3 tt, cun cam L se hoan tra lai in nng di dang in ap ng va luc nay diode D dn in va cho nap dong in ng vao tu C.

Nguyn ly dung tao ng ngun co cc ra m nh sau: Khi Q1, Q2 dn in, luc nay cun dy L c cho nap in nng va no tich tr in nng di dang t trng, khi Q1, Q2 tt, cun dy L se hoan tra lai lng in nng tich tr di dang in ap ng, luc nay diode D se dn in va cho nap dong ng vao tu C (470uF), vi cach mc cua mach trn, nga ra chung ta se co mc ap m. Mc ap m cao hay thp se phu thuc vao tri cua hai in tr ly tin hiu hi tip FB. Vi tri in tr co trong mach nay, chung ta se ly c mc ap ra la -12V, va dong cp cho tai la 100mA. Noi thm cho ro:

Mt ln na Ban lai thy ngi ta tim cach khai thac in ap ng cua cun cam L tao ra mc ap m trn tu C. Khi khoa K ong la luc cun cam c cho nap dong va no tich tr in nng va khi khoa K h, ct dong cua ngun chay qua cun dy, luc nay cun dy se phat ra in ap ng. Nu bit cach dung diode nn dong, chung ta se ly c dong ng cho nap vao tu co ngun in ap m cp cho tai.

Hoat ng cua mach 6 ging nh mach 5, chi khac la mach dung thm transistor ngoai Q3, y Q3 la loai transistor pnp lam vic nh mt khoa in ong m nhanh, khi Q3 dn no bm dong vao cun cam L va khi Q3 tt no in ap ng cua cun dy L cho nap dong ng vao tu C va tao ra ngun volt m. Dung hai in tr inh h s hi tip nghich qua o xac inh mc ap nga ra. Vi Q3 mach se co kha nng cp dong ln hn cho tai. Ban co th dung iu bin rng xung thay i mc sang cua Led. 1. Cach thc iu chinh mc sang cua cac Led trong mach in dang xung.

Xung chm, thy Led nhp nhay thay i

Xung nhanh, mc sang Led

Vi cac mach dung xung on/off tt m cac Led, iu chinh mc sang cua Led, Ban phai dung xung iu bin rng nhip nhanh iu chinh mc sang cua Led.

* Hinh ve cho thy vi xung co h s duty 50 % thi trong mt chu ky tin hiu thi gian cho Led sang bng thi gian cho Led tt, nh vy Led se co mc sang trung binh.

* Vi xung co h s duty nho, nh 25 % thi trong mt chu ky tin hiu thi gian cho Led sang ngn hn thi gian cho Led tt, nh vy Led se co mc sang yu hn. * Vi xung co h s duty ln, nh 75 % thi trong mt chu ky tin hiu thi gian cho Led sang dai hn thi gian cho Led tt, nh vy Led se co mc sang manh hn. Phn tich nay cho thy trong cac mach in lam vic vi tin hiu dang xung, cac Led chi lam vic theo trang thai sang hay tt, thi vic iu chinh mc sang cua cac Led la phai dung n cac xung PWM, hay con goi la xung iu bin rng. Vy, h s Duty la gi?

Ngi ta inh nghia, trong mt chu ky xung, ty s gia thi gian Ton trn chu ky T la h s duty. Vy thi gian Ton cang dai thi h s duty cang ln. Mt thi du hiu h s duty: Nu trong mt ngay 24 gi, chung ta lam vic 12 gi va nghi 12 gi thi h s duty se la 50%. Vy s gi lam vic cang it h s duty se cang nho va s gi lam vic nhiu h s duty se ln. Trong cac mach in lam vic vi xung, do tn s cua xung n inh, nghia la chu ky xung khng thay i, luc o ngi ta se dung h s duty iu khin cac hoat ng cua mach. y la

mt dang xung iu bin rng, vn nay chung ta se gp trong cac mach s, nh cac mach lam cho cac Led nhp nhay iu khin bi cac ic lp trinh, ic logic... 2. Xem mt thi du: Mach iu ch rng cua xung rap vi IC 555.

Nguyn ly lam vic cua mach nh sau: * Thi ky Ton Khi chn s 3 mc volt cao, luc nay chn 7 h : masse, tu C2 nap dong qua RV', qua diode D13, va qua in tr 1K, va khi mc ap trn chn 2, 6 ln bng mc 8V (2/3 mc ngun) thi chn s 3 se chuyn nhanh xung mc volt thp, va cung luc no cho chn s 7 ong masse.

* Thi ky Toff Khi chn s 3 mc volt thp, luc nay chn : 7 ong masse, tu C2 xa dong qua RV'', qua diode D14, va khi mc ap trn chn 2, 6 xung bng mc 4V (1/3 mc ngun) thi chn s 3 se chuyn nhanh xung mc volt cao, va cung luc no cho chn s 7 h masse. Quy trinh trn c lp i lp lai va chu ky cua tin hiu xung ra trn chn s 3 se la: T 0.69 (RV' + 1K + RV'')C = 0.69(50K + 1K)0.1 ... la mt hng s. Vi : Ton = 0.69 (RV'+1K)C va: Toff = 0.69(RV'')C

Duty = Ton/T , no la mt ham cua RV', vy khi chinh chit ap RV, Ban thay i RV' va rng cua xung co dang iu bin va Ban se thy mc sang cua cac Led thay i. Nhn Ban: hiu ro hn v IC 555, Ban tham khao bai vit sau:

Click chut vao dong nay m xem.

3. Lam mach Led nhay theo tin hiu nhac. Tim hiu IC phat cac ban nhac khuc: UM66

Cac d liu trn cho thy, IC nhac UM66 co hinh dang nh mt transistor TO92, no co 3 chn, chn gia cho ni masse, chn bn phai ni vao ngun dng 3V, chn bn trai cho ra cac xung iu bin, vi ni dung la cac ip khuc quen thuc. UM66 co nhiu phin ban, phn bit theo cac ch phu ghi thm

bn sau, mi phin ban co cac ip khuc nhac khac nhau. Cach dung IC UM66 rt n gian. Cac s ng dung in hinh nh sau:

Nu UM66 dung vi loa gm thi do loa gm co tr khang ln nn co th cho ni thng vao chn Out ly tin hiu, nu dung loa in ng co ni tr nho thi phai thm tng khuch ai. Mach dung transistor 9013 vi in tr 4.7K han dong trn chn B, loa gn trn chn C. Vi cac mach in nay, mi khi Ban nhn nut SW, mach c cp in va t loa se phat ra cac ip khuc nhac nghe quen tai. Nu Ban dung may hin song xem cac tin hiu nhac phat ra t IC UM66 Ban se thy no la mt chui xung iu bin rng, nghia la bin tin hiu khng thay i, lun la xung vung, cac xung chi thay i rng ma thi, o cung la mt c im cua cac nhac cu in t.

Ban co th dung nhac khuc phat ra t IC UM66 kich sang mt bang en Led. Mt s ng dung nh hinh sau:

Trong mach dung IC UM66 phat ra tin hiu nhac (cac ip khuc), o la cac day xung iu bin rng, IC UM66 c cp ngun ly trn 2 Led D7, D8, in tr R1 dung han dong va tu C2 co tac dung n ap ng ngun 3.8V. Tin hiu nhac phat ra t chn s 1, cho vao chn B cua transistor Q1 c khuch ai, trn chn C cua Q1 chung ta dung transistor pnp Q3 khuch ai, cp tin hiu u ln cho loa in ng, va dung transistor npn Q2 khuch ai, tao tinh tt m cho cac Led trn bang en, cac Led nay se nhp nhay theo iu nhac. Khi co xung ra bin cao thi Led se sang va khi xung mc bin thp thi Led tt, Ban co th gn thm diode 4148 mc ni tip vi in tr han dong 4.7K trn chn B cua Q2 tng rao ap, tao tinh ngng dn tt cho Q2. Nhin chung mach rt n gian d rap, c hi thanh cng cao.

Mt gi y: Ban co th lam bang en Led chay ngun pin Lithium 3.6V

Ti nghi oc qua bai vit nay, Ban co th t cho kt hp cac mach in co mt kiu mach theo ung y mun cua Ban. Thi du: co bang en Led chay vi mc ngun nui thp. Ban co th dung IC nng ap 34063A, nng mc ap 3V ln mc ap 12V hay ln n 30V. Dung IC UM66 co tin hiu nhac, cho kt hp cac mach in nay lai la a co mt bang en Led siu sang nhay theo iu nhac. Phn nay Ban t thit k. Th xem!!!

Phu LucBan co th dung AT89C2051 cho Led nhay theo iu nhac.

Trong cac bai vit trc y, chung ta thy vi cac ic lp trinh, nh AT89C51, AT89C2051... chung ta a co th lam c rt nhiu vic thich thu. Trong bai nay ti thm phn phu luc noi v cach dung ic lp trinh vit cac chng trinh nhac, phn tich cach vit cac chng trinh ngun va ri tim cach dung cac chng trinh nay iu khin cac bang en Led. Mong Ban thich tai nay.

Trc khi mun vit mt chng trinh ngun dung ic lp trinh cho phat ra tin hiu nhac, Ban cung phai bit tin hiu nhac c tao ra nh th nao?

Hinh ve cho thy, s thay i cua r6 se tao ra cac nt nhac khac nhau, va s thay i cua r7 se tao ra cac trng khac nhau. Chung ta bit trong mt iu nhac gm co 2 phn: Phn nt nhac va phn trng , phu thm la khoang dng va du hiu ht bai. Nt nhac gm co nt: Do Re Mi Fa Sol La Si ng vi 7 con s la 1 2 3 4 5 6 7. V mt vt ly mi nt nhac la mt tin hiu co mt tn s xac inh. Sau y la tn s cua tin hiu ng vi 7 nt nhac trn. Do (523Hz) - Re (587Hz) - Mi (659Hz) - Fa (698Hz) - Sol (784Hz) - La (880Hz) - Si (988Hz). * Vn tao ra cac nt nhac: Trong chng trinh ngun bn di chung ta dung thanh ghi r6 cho phat ra nt nhac. Chung ta co th tao ra xung vi tn s xac inh tuy theo tri nap vao thanh ghi r6. Thi du: Trong chng trinh ngun bn di, vi thach anh 12MHz, khi tri trong r6 la 1 thi thi gian tr se la 20us. Vy tao ra tin hiu co tn s la 200Hz, chung ta se phai nap tri la bao nhiu vao thanh ghi r6?

Cach tinh nh sau: Vi: nu co tin hiu co tn s la f = 200Hz thi chu ky xung se la: T = 1/200Hz = 5ms hay 5000us, vy na ban ky cua xung se la 2500us, nu chia cho 20us, chung ta co con s 125 hay 7dh. Vy nu Ban nap con s 125 hay 7dh vao thanh ghi r6, chung ta se co tin hiu co tn s 200Hz. Qua thi du nay Ban bit cach tinh ra tri thp phn hay tri thp luc phn nap vao thanh ghi r6, ic lp trinh phat ra tin hiu cac nt nhac co tn s nh trn. Trong cach lam, Ban se tinh tri thp luc phn tng ng vi 7 nt nhac trn va khi cn co nt nhac nao, Ban chi vic cho nap tri a tinh c vao thanh ghi r6. * Vn trng cua cac nt nhac: keo dai thi gian cho phat ra mt nt nhac, chung ta se dung timer0 iu khin trng phat cac nt nhac. Trong chng trinh nay chung ta dung timer 0 tao ra khoang thi chun la 10ms va dung ngt iu khin khoang thi gian phat ra cua cac nt nhac, khoang thi gian nay tuy thuc vao tri trong r7. Thi du, nu chung ta qui inh trong 1phut co 94 nhip hay phach, thi thi gian cho 1 nhip se la 1/94 hay 0.64s. Vy 1/4 nhip se la 0.64s/4 = 0.16s hay 160ms = 16x10, 10 ln cua 10ms se tao ra trng la 1/4 nhip. co trng 3 nhip, thi gian se la 0.64sx3 = 1.92s hay 1920ms = 192x10ms. 192 ln cua 10ms se tao ra trng la 3 nhip. Nh vy chung ta inh c s ln cho ngt inh trng cua cac nt nhac. * Vn khoang dng va ma kt thuc ban nhac: Chung ta co th dung ma 00h t trong bang anh du s kt thuc cua ban nhac va dung ma 0ffh tao khoang dng.

Sau y la mt chng trinh ngun a gian lt tao ra tin hiu nhac. Tin hiu cho xut trn chn p1.7

ORG

0000H ; khi u t ia chi thanh nh 0000h JMP START ; nhy n tn nhan start

ORG 000BH ; vi tri dung cho ngt timer 0, nhy ngt theo bit tf0 ; chng trinh cua ngt timer 0 INC 20H ; cho tng tri trong thanh 20h ln +1 MOV TH0,#0D8H ; Nap tri vao thanh m th0 cua timer 0 MOV TL0,#0EFH ; Nap tri cho thanh m tl0. Vi thanh anh 12MHz, timer0 cho inh la 10ms RETI ; dng chng trinh ngt quay lai chng trinh chinh. START: th0 ; tn nhan dung cho lnh nhy MOV SP,#50H ; chon vung lam ngn xp MOV TH0,#0D8H ; nap tri inh trc cho thanh m

MOV TL0,#0EFH ; nap tri inh trc cho thanh m tl0 MOV TMOD,#01H ; khai bao dung mode 1 cho timer 0, mode m 16 bit MOV IE,#82H ; khai bao cho dung ngt theo bit bao tran tf0 ; Dung timer0 cho chay mode 1 tao thi gian chun la 10ms MUSIC0: ; tro 20h MOV MOV MOV ; t tn NOP ; dong DPTR,#DAT 20H,#00H B,#00H nhan cho lnh nhy khng tac vu ; t bang dat vao thanh ghi con ; nap tri 0 khi u vao thanh ghi ; nap tri 0 vao thanh ghi b

MUSIC1:

t tn nhan dung cho lnh nhy NOP ; dong khng tac vu CLR A ; cho xoa sach thanh ghi a MOVC A,@A+DPTR ; ly ma trong bang cho ct vao thanh a JZ END0 ; xet tri trong thanh a, bng 0 cha chon hng nhy CJNE A,#0FFH,MUSIC5 ; cho so tri trong a vi tri 0ffh chon hng nhy JMP MUSIC3 ; nhy n tn nhan la music3

MUSIC5:

t tn nhan dung cho lnh nhy NOP ; dong khng tac vu MOV R6,A ; cho ct tri trong thanh a vao thanh r6 INC DPTR ; cho tng tri trong dptr ln +1 ly ma tip theo MOV A,B ; chuyn tri trong thanh b vao thanh a MOVC A,@A+DPTR ; cho ly ma trong bang ct vao thanh a MOV R7,A ; chuyn tri trong thanh a vao thanh r7 SETB TR0 ; cho chay mach timer 0, nhy ngt theo bit bao tran MUSIC2: p1.7 CPL ; t tn nhan dung cho lnh nhy NOP ; dong khng tac vu P1.7 ; ly bu va cung cho xut tin hiu trn chn

;

MOV A,R6 ; tra tri trong thanh r6 tr lai thanh a MOV R3,A ; chuyn tri trong thanh a vao thanh r3 CALL DEL ; goi chng trinh tr co tn nhan del MOV A,R7 ; tra tri trong thanh r7 tr vao thanh a CJNE A,20H,MUSIC2 ; so tri trong a vi tri trong 20h inh hng nhy MOV 20H,#00H INC DPTR JMP MUSIC1 ; tra tri 0 vao thanh ghi 20h ; cho tng tri trong thanh ghi con ; nhy n tn nhan music1

tro

MUSIC3: ; t tn nhan dung cho lnh nhy NOP ; dong khng tac vu CLR TR0 ; tt mach m cua timer 0 ; tao khoang dng 100ms MOV R2,#0DH ; t tri s m 0dh vao thanh r2 MUSIC4: ; t tn nhan dung cho lnh nhy NOP ; dong khng tac vu MOV R3,#0FFH ; t tri 0ffh vao thanh r3 CALL DEL ; goi chng trinh tr co tn nhan la del DJNZ R2,MUSIC4 ; giam tri trong r2, r2=0? chon hng

nhy ln

INC JMP

DPTR MUSIC1

; cho tng tri trong thanh ghi con tro +1 ; nhy n tn nhan music1

END0: ; t tn nhan dung cho lnh nhy NOP ; dong khng tac vu ; Tao khoang dng 1s MOV R2,#64H ; t tri s m 64h vao thanh r2 MUSIC6: ; t tn nhan dung cho lnh nhy MOV R3,#00H ; t tri 00h vao thanh ghi r3 CALL DEL ; goi chng trinh lam tr co tn nhan la del DJNZ R2,MUSIC6 ; giam tri trong r2, r2=0?, chon hng nhy JMP MUSIC0 ; nhy n tn nhan la music0 DEL: ; t tn nhan dung cho lnh nhy, tr thay i theo r3 NOP DEL3: ; t tn nhan dung cho lnh nhy MOV R4,#02H ; t tri s m 02h vao r4 DEL4: ; t tn nhan dung cho lnh nhy NOP DJNZ R4, DEL4 ; giam tri trong r4 theo bc -1, r4=0?, chon hng nhy NOP DJNZ R3,DEL3 ; giam tri trong r3 theo bc -1, r3=0?, chon hng nhy RET ; quay lai sau lnh call del NOP DAT: ; bang t cac cp ma: nt nhac va trng ... cua mt ban nhac db 26h,20h,20h,20h,20h,20h,26h,10h,20h,10h,20h,80h,26h,20h,3 0h,20h db 30h,20h,39h,10h,30h,10h,30h,80h,26h,20h,20h,20h,20h,20h,1 ch,20h db 20h,80h,2bh,20h,26h,20h,20h,20h,2bh,10h,26h,10h,2bh,80h,2

6h,20h db 30h,20h,30h,20h,39h,10h,26h,10h,26h,60h,40h,10h,39h,10h,2 6h,20h db 30h,20h,30h,20h,39h,10h,26h,10h,26h,80h,26h,20h,2bh,10h,2 bh,10h db 2bh,20h,30h,10h,39h,10h,26h,10h,2bh,10h,2bh,20h,2bh,40h,4 0h,20h db 20h,10h,20h,10h,2bh,10h,26h,30h,30h,80h,18h,20h,18h,20h,2 6h,20h db 20h,20h,20h,40h,26h,20h,2bh,20h,30h,20h,30h,20h,1ch,20h,2 0h,20h db 20h,80h,1ch,20h,1ch,20h,1ch,20h,30h,20h,30h,60h,39h,10h,3 0h,10h db 20h,20h,2bh,10h,26h,10h,2bh,10h,26h,10h,26h,10h,2bh,10h,2 bh,80h db 18h,20h,18h,20h,26h,20h,20h,20h,20h,60h,26h,10h,2bh,20h,3 0h,20h db 30h,20h,1ch,20h,20h,20h,20h,80h,26h,20h,30h,10h,30h,10h,3 0h,20h db 39h,20h,26h,10h,2bh,10h,2bh,20h,2bh,40h,40h,10h,40h,10h,2 0h,10h db 20h,10h,2bh,10h,26h,30h,30h,80h,00H END * Nu Ban thay dung bang ma sau y cho chng trinh ngun trn, Ban se co ban nhac: Thang 8 hoa Qu toa hng thm. DAT: DB DB ; Ban nhac "Thang 8 hoa Qu toa hng thm" 18H, 30H, 1CH, 10H 20H, 40H, 1CH, 10H

DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB DB

18H, 1CH, 1CH, 1CH, 20H, 30H, 20H, 20H, 40H, 20H, 20H, 20H, 18H, 26H, 30H, 20H, 18H, 26H, 30H, 20H, 18H, 1CH, 26H, 2BH, 20H, 20H, 20H, 20H, 2BH, 2BH, 1FH, 1CH, 26H, 30H, 20H, 18H, 1CH, 26H, 2BH, 20H, 20H,

10H, 10H, 20H, 20H, 1CH, 15H, 20H, 20H, 26H, 20H, 10H, 20H, 20H, 20H, 10H, 20H, 20H, 30H, 20H, 20H, 40H, 20H, 20H, 30H, 10H, 20H, 20H, 40H, 05H, 10H, 20H, 20H, 30H, 20H, 20H, 40H, 20H, 20H, 30H,

80H,

20H, 18H, 20H, 18H, 10H, 20H, 20H, 20H, 20H, 1CH, 20H, 2BH, 2BH, 1CH, 20H, 2BH, 2BH, 1CH, 15H, 20H, 20H, 26H, 30H, 1CH, 1CH, 26H, 30H, 20H, 20H, 20H, 2BH, 2BH, 1CH, 15H, 20H, 20H, 26H, 30H, 1CH,

30H,

10H 40H 20H 20H 0FFH,20H 18H 1CH 26H 2BH 20H 80H, 0FFH 10H 20H 20H 40H 10H 20H 20H 40H 10H 20H 20H 20H 20H 80H 10H 10H 20H 20H 15H 10H 20H 20H 40H 10H 20H 20H 20H 20H 30H 10H

DB 18H, DB 20H, DB 13H, DB 15H, DB 18H, 80H, 00H

40H, 20H, 60H, 40H,

1CH, 26H, 18H, 13H,

20H 40H 20H 40H

* y la bang ma cho phat ban nhac: Chuc Ban binh an DAT: db 26h,20h,20h,20h,20h,20h,26h,10h,20h,10h,20h,80h,26h,20h,3 0h,20h db 30h,20h,39h,10h,30h,10h,30h,80h,26h,20h,20h,20h,20h,20h,1 ch,20h db 20h,80h,2bh,20h,26h,20h,20h,20h,2bh,10h,26h,10h,2bh,80h,2 6h,20h db 30h,20h,30h,20h,39h,10h,26h,10h,26h,60h,40h,10h,39h,10h,2 6h,20h db 30h,20h,30h,20h,39h,10h,26h,10h,26h,80h,26h,20h,2bh,10h,2 bh,10h db 2bh,20h,30h,10h,39h,10h,26h,10h,2bh,10h,2bh,20h,2bh,40h,4 0h,20h db 20h,10h,20h,10h,2bh,10h,26h,30h,30h,80h,18h,20h,18h,20h,2 6h,20h db 20h,20h,20h,40h,26h,20h,2bh,20h,30h,20h,30h,20h,1ch,20h,2 0h,20h db 20h,80h,1ch,20h,1ch,20h,1ch,20h,30h,20h,30h,60h,39h,10h,3 0h,10h db 20h,20h,2bh,10h,26h,10h,2bh,10h,26h,10h,26h,10h,2bh,10h,2 bh,80h

db 18h,20h,18h,20h,26h,20h,20h,20h,20h,60h,26h,10h,2bh,20h,3 0h,20h db 30h,20h,1ch,20h,20h,20h,20h,80h,26h,20h,30h,10h,30h,10h,3 0h,20h db 39h,20h,26h,10h,2bh,10h,2bh,20h,2bh,40h,40h,10h,40h,10h,2 0h,10h db 20h,10h,2bh,10h,26h,30h,30h,80h,00H Giai thich y nghia cac cu lnh dung trong chng trinh ngun: (1) Dung Timer 0, chon mode 1, tao ra thi chun 10ms

co thi chun 10ms dung chon inh trng phat ra cua cac nt nhac, ngi ta dung timer0, cho lam vic mode

1, vi cac tri a nap vao thanh m tl0, th0 la th0 0d8h=216 va tl0 la 0efh=239 thi b m chi cn m thm 10000us=10ms na la tran. Ban hiu ro hn v hoat ng cua ng h timer0, chung ta se khao sat hinh ve sau:

Hinh ve cho thy vi thach anh 12MHz thi chu ky xung vao mach m se la 1us, vi thanh m 16 bit tao bi 2 thanh tl0 va th0 thi b m nay co th m c ti a la 65535 xung, hay 65525us, nhng do chung ta a cho nap trc vao 2 thanh tl0 va th0 tri d8efh, tc la 55355, nn b m chi cn m thm 10000us na la tran, tc la 10ms. dung timer0, mode 1, chung ta dung cac cu lnh sau: mov tmod, #01h ; tc t bit 00000001b vao thanh tmod. mov th0, #0d8h ; tc t tri 0d8h=216 vao thanh m th0 mov tl0, #0efh ; tc t tri 0efh=239 vao thanh m tl0 m mach m chung ta dung cu lnh: setb tr0 va dng m chung ta dung cu lnh: clr tr0.

y chung ta khai bao nh sau, trong thanh IE, dung ngt theo bit bao tran tf0.

Dung cu lnh: setb tr0 cho m b m cua timer 0, va khi b m tran s, m n 65535 nhip, bit bao tran bc ln 1, ngay luc nay se nhy ngt tf0, chng trinh chinh se dng lai, nhy n ia chi 000bh va cho thc hin cac cu lnh bn di ia chi nay...cho n khi gp cu lnh:reti, no se dng thc hin chng trinh ngt va quay lai thc hin tip chng trinh chinh a dng lai luc trc. (2) Dung cac cu lnh ly ma nt nhac va ma trng trong bang. Chung ta bit trong bang ma vi tn nhan la dat: , trong o ngi ta a t tng cp ma, trc lama nt nhac va k bn la ma trng . ly cac ma nay cho phat ra trn chn p1.7 (hay co th trn cac chn khac tuy chon), chung ta se dung cac cu lnh c giai thich nh sau: MUSIC0: ; thanh MOV MOV t tn NOP ; dong DPTR,#DAT ghi 20H,#00H nhan cho lnh nhy khng tac vu ; t ia chi cua bang dat vao con tro dph va dpl ; nap tri 0 khi u vao thanh ghi

20h

MOV

B,#00H

; nap tri 0 vao thanh ghi b

Giai thich: dung thanh ghi co ia chi 20h lam thanh ghi ct gi s m s ln a nhy ngt. Dung thanh ghi b gi s ln a ly ma trng MUSIC1: tri 0 CLR ; t NOP ; A tn nhan dung cho lnh nhy dong khng tac vu ; cho xoa sach thanh ghi a, ly

MOVC A,@A+DPTR ; ly ma vi tri 0 trong bang cho ct vao thanh a JZ END0 ; xet tri trong thanh a, bng 0 cha chon hng nhy CJNE A,#0FFH,MUSIC5 ; cho so tri trong a vi tri 0ffh chon hng nhy JMP MUSIC3 ; nhy n tn nhan la music3 Giai thich: Trc ht cho xoa tri trong thanh clr a, ri cho ly ma u tin trong bang cho ct vao thanh a. Xet xem tri trong thanh a co bng 0 khng?. Nu cha bng 0 thi xung cu lnh di, nu bng 0 thi nhy n tn nhan END0, chay chng trinh kt thuc ban nhac. Cu lnh: CJNE cho km tra tri trong a co la 0ffh khng? Nu khng thi nhy n tn nhan MUSIC5 tip tuc cho phat nhac.....Nu a bng 0ffh thi xung chay cu lnh jmp music3, music3: la chng trinh cho dng 100ms. MUSIC5: t tn nhan dung cho lnh nhy NOP ; dong khng tac vu MOV R6,A ; cho ct tri trong thanh a vao thanh r6 INC DPTR ; cho tng tri trong dptr ln +1 ly ma tip theo MOV A,B ; chuyn tri trong thanh b vao thanh a MOVC A,@A+DPTR ; cho ly ma trong bang ct vao thanh a MOV R7,A ; chuyn tri trong thanh a vao thanh r7 SETB TR0 ; cho chay mach timer 0, nhy ngt theo bit bao tran ;

Giai thich: By gi cho chuyn ma nt nhac co trong a ct vao thanh ghi r6, dung cu lnh: inc dptr cho di ma trong bang ln mt bc. Chuyn tri cua thanh b vao thanh a va lai cho ly ma trong bang, ln nay ly la ma trng , lai cho ct ma trng vao thanh ghi r7. Bt u cho chay timer 0 vi cu lnh: setb tr0 dung ngt tf0. Tom lai oan chng trinh trn cho thy, chung ta a ly ma nt nhac trong bang cho ct vao thanh ghi r6 va ly ma trng cho ct vao thanh ghi r7, cung luc kim tra ma trng trong a co la 00h hay khng? hay co la 0ffh hay khng? Nu trong a la ma 00h thi cho kt thuc ban nhac, cho nghi 1s ri lp lai, nu trong a la ma 0ffh thi dng 100ms ri tip tuc. (3) Cach phat tin hiu nhac ra trn chn chung ta chon la p1.7 MUSIC2: p1.7 CPL ; t tn nhan dung cho lnh nhy NOP ; dong khng tac vu P1.7 ; ly bu va cung cho xut tin hiu trn chn

MOV A,R6 ; tra tri trong thanh r6 tr lai thanh a MOV R3,A ; chuyn tri trong thanh a vao thanh r3 CALL DEL ; goi chng trinh tr co tn nhan del MOV A,R7 ; tra tri trong thanh r7 tr vao thanh a CJNE A,20H,MUSIC2 ; so tri trong a vi tri trong 20h inh hng nhy MOV 20H,#00H INC DPTR JMP MUSIC1 ; tra tri 0 vao thanh ghi 20h ; cho tng tri trong thanh ghi con ; nhy n tn nhan music1

tro

Giai thich: Cu lnh: cpl p1.7 dung cho xut tin hiu nhac trn chn p1.7. Ln xut nay la ma nt nhac, nt nhac la mt xung co tn s a bit, tn s xung xac inh theo tri co trong thanh ghi r6, y cho chuyn tri cua r6 vao thanh ghi r3 ri dung lnh goi: call del, chay chng trinh inh thi gian tr, thi gian tr tuy thuc vao tri trong r3, vi tri trong r3 cang

ln thi gian tr dai se tao ra xung co tn s thp va ngc lai nu tri trong r3 nho chung ta se co xung tin hiu tn cao. K o cho chuyn tri trong thanh ghi r7 vao thanh a, tri trong thanh ghi r7 la ma trng , tc dai cua nt nhac ma chung ta cho phat ra trn chn p1.7. Hay cho so sanh tri co trong thanh 20h va tri trong thanh ghi a (tc tri cua r7) bit s ln nhy ngt a u theo tri trong thanh ghi r7 cha. Nu cha thi tip tuc cho nhy ngt n khi tri trong 20h bng tri trong thanh r7. Trc khi nhy tr lai tn nhan music1 tip tuc..., chung ta khng qun tra tri trong thanh ghi 20h v 0 va ng thi cho di ma trong bang ln mt bc vi cu lnh: inc dptr. Tom lai, ma nt nhac co tn s inh theo tri trong r6, tn s ly theo thi gian tr trong chng trinh del: va ma trng co dai xac inh theo tri trong thanh ghi r7, thi gian dai ngn la mt bi s cua ngt timer 0, tc ly theo s ln cua thi chun 10ms. DEL: ; t tn nhan dung cho lnh nhy, tr thay i theo r3 NOP DEL3: ; t tn nhan dung cho lnh nhy MOV R4,#02H ; t tri s m 02h vao r4 DEL4: ; t tn nhan dung cho lnh nhy NOP DJNZ R4, DEL4 ; giam tri trong r4 theo bc -1, r4=0?, chon hng nhy NOP DJNZ R3,DEL3 ; giam tri trong r3 theo bc -1, r3=0?, chon hng nhy RET ; quay lai sau lnh call del (4) Tao khoang dng 100ms ng vi ma trng 0ffh ly c t trong bang dat: MUSIC3: ; t tn nhan dung cho lnh nhy NOP ; dong khng tac vu CLR TR0 ; tt mach m cua timer 0 ; tao khoang dng 100ms MOV R2,#0DH ; t tri s m 0dh vao thanh r2

MUSIC4: ;

del nhy ln

t tn nhan dung cho lnh nhy NOP ; dong khng tac vu MOV R3,#0FFH ; t tri 0ffh vao thanh r3 CALL DEL ; goi chng trinh tr co tn nhan la R2,MUSIC4 ; giam tri trong r2, r2=0? chon hng DPTR MUSIC1 ; cho tng tri trong thanh ghi con tro +1 ; nhy n tn nhan music1

DJNZ INC JMP

Giai thich: Trc ht cho tt timer 0 vi cu lnh: clr tr0, ri t tri 0dh=13 vao thanh ghi r2, y la mt s m. Luc nay t tri 0ffh=255 vao thanh ghi r3, ri cho goi chng trinh lam trdel: , dung cu lnh: call del. Qui trinh nay cho lp lai n khi tri trong thanh ghi r2 giam theo bc -1 cho n bng 0. Trc khi quay lai tn nhan music1, Ban khng qun cho di ma trong bang dat: ln mt bc vi cu lnh: inc dptr. Vy mi khi ly c ma trng co tri la 0ffh, thi chung ta se cho chng trinh nhy n tn nhan music4: cho chay chng trinh lam tr 100ms. (5) Tao khoang dung 1s ng vi ma trng 00h ly c t trong bang dat: END0: ; t tn nhan dung cho lnh nhy NOP ; dong khng tac vu ; Tao khoang dng 1s MOV R2,#64H ; t tri s m 64h vao thanh r2 MUSIC6: ; t tn nhan dung cho lnh nhy MOV R3,#00H ; t tri 00h vao thanh ghi r3 CALL DEL ; goi chng trinh lam tr co tn nhan la del DJNZ R2,MUSIC6 ; giam tri trong r2, r2=0?, chon hng nhy JMP MUSIC0 ; nhy n tn nhan la music0 Giai thich: Khi ly ma trng trong bang gp tri 00h thi chng trinh se nhy n tn nhan end0: y la chng trinh lam tr 1s. Chng trinh nay c vit nh sau: Trc ht t

tri s m 64h=100 vao thanh r2. t tri 00h vao thanh ghi r3 va cho goi chng trinh tr vi cu lnh:call del. Kim tra tri trong r2 xem bng khng cha inh hng nhy. Nu tri trong r2 a giam n mc bng 0 thi nhy v tn nhan music0 cho khi u lai. end ; la mt gia lnh, co nghia la dng bin dich tai dong nay