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Phn I Tm hiu mt s linh kin8255
1. Cu trc ca 8255Vi mch 8255 l vi mch c ln LSI, thng c gi l mch phi ghp vo/ra
song song lp trnh c. Do kh nng mm do trong cc ng dng thc t n l
mch phi ghp c dng rt ph bin cho cc h vi x l 8, 16, 32 bit, Vi mch 40chn ny c cc chn nh sau:
U1
8255
3433323130292827
53698356
432140393837
181920212223
2425
1415161713121110
D0D1D2D3D4D5D6D7
RDWRA0A1RESET
CS
PA0PA1PA2PA3PA4PA5PA6PA7
PB0PB1PB2PB3PB4
PB5PB6PB7
PC0PC1PC2PC3PC4PC5PC6PC7
C 24 ng dn li vo/ra xp thnh 3 cng song song ( portA, portB, portC).Mt na cng C ( PC4 PC7) thuc nhm A, cn na kia thuc nhm B.
Chn Reset phi c ni vi tn hiu Reset chung ca ton h thng (khi Reset
cc cng c nh ngha l cng vo khng gy ra s c cho cc mch iukhin).
Tn hiu CS c ni ci mch to xung chn thit b t mch 8255 vo mta ch c s no . Cc tn hiu a ch A0, A1 s chn ra 4 thanh ghi bn trong8255: mt thanh ghi ghi t iu khin (CWR control word register) cho hotng ca 8255 v 3 thanh ghi khc ng vi cc cng l PA, PB, PC ghi c dliu theo bng:
A1 A0 CS RD WR Lnh (ca VXL)Hng chuyn s liu vi
VXL
0 0 0 0 1 c PortA PortAD0 D70 1 0 0 1 c PortB PortBD0 D71 0 0 0 1 c PortC PortC D0 D71 1 0 0 1 Khng c gi tr0 0 0 1 0 Ghi PortA D0 D7 PortA0 1 0 1 0 Ghi PortB D0 D7 PortB1 0 0 1 0 Ghi PortC D0 D7 PortC1 1 0 1 0 Ghi thanh ghi
iu khinD0 D7 Thanh ghi
iu khin
x X 1 x X Vi mch trngthi tr khngcao
Khng c trao i s liu
Tm hiu mt s linh kin3
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Tnh linh hot ca vi mch ny th hin kh nng lp trnh. Ta c th t ccmode hot ng thng qua thanh ghi iu khin. Cc chn D0 D7 to nn knh dliu 2 hng c rng 8 bit. Tt c d liu khi truy nhp ghi hoc c c dn quaknh d liu ny.
Trng thi logic ghi/c c nhn bit qua cc tn hiu iu khin CS ,RD , WR .Trao i thng tin vi 8255 ch c th c tin hnh khi CS = 0. Khi RD = 0 d liuca cng c chn c a ra knh d liu v c th c s dng bi cc vi mchkhc. Khi WR = 0, th moi vic xy ra ngc li. Cc bit a ch A0 v A1 cng vicc tn hiu ghi c bo cho bit s truy nhp ln cng no.
S khi m t chc nng ca 8255:
D0D7
RD
WR
A1
A0
Reset
2. Cc ch lm vic ca 8255C 2 loi t iu khin cho 8255:
T iu khin nh ngha cu hnh cho cc cng PA, PB, PC. T iu khin lp/xo tng bit u ra ca PC.
Tu theo lnh ghi vo thanh ghi iu khin khi khi ng vi mch m ta ccc PortA,B,C hot ng :
Cc ch 0, 1, 2 khc nhau.
Tm hiu mt s linh kin4
PortA
(8)
PortCna
cao (4)
PortCnathp(4)
PortB
(8)
iu
khinnhmA
iukhinnhm
B
ms liu
Logicikhincghi
A0PA7
C7PC4
C3PC0
8
4
4
8
B0PB7
CS
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Chiu trao i s liu khc nhau.2.1. T iu khin nh ngha cu hnh cho cc cngDng thc t iu khin nh ngha cu hnh cho 8255:
D7 D6 D5 D4 D3 D2 D1 D0
C =1 MA1 MA0 A CA MB B CB
Nhm AChn ch 00: mode 001: mode 11x: mode 2
2.2. T iu khin lp xo bit ra PCiDng thc ca t iu khin d lp xo PCi:
D7 D6 D5 D4 D3 D2 D1 D0
0 0 0 0 S/R
1 1 1 1 0 0 0 0
1 1 0 0 1 1 0 0
1 0 1 0 1 0 1 0
Cc ch lm vic ca 8255 c th c nh ngha bng t iu khin
CWR. 8255 c 3 ch lm vic: Mode 0: Vo/ra c s. Trong ch ny mi cng PA, PB, PCH
v PCL u c th c nh ngha l cc cng vo hoc ra. Mode 1: Vo/ra c xung cho php. Trong ch ny mi cng
PA,PB c th c nh ngha thnh cng vo hoc ra vi cc tnhiu mc ni ( handshaking ) do cc bit tng ng ca cng PCtrong cng nhm m nhn.
Mode 2: Vo/ra 2 chiu. Trong ch ny ch ring cng PA cth c nh ngha thnh cng vo ra 2 chiu vi cc tn hiu mc
Tm hiu mt s linh kin5
PA:1: vo0: ra
PCH:
1: vo0: ra
Nhm BPC
L(thp):
1: vo0: ra
PB:1: vo
0: ra
Chn ch :1: vo0: ra
1: Lp PCi
0: Xo PC
PC7PC6 PC5PC4 PC3 PC2PC1 PC0
3 bit a ch
ca 8 bit PC
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ni do cc bit ca cng PC m nhim. Lc ny cng PB c thlm vic trong ch 0 hoc 1.
Trong ch 0, ngi ta c th dng cc bit ca PC lp xo iu khinhoc i thoi vi cc thit b ngoi vi, ch ny cn gi l ch lp xotng bit ca PC:
Ghp ni 8255 vi h vi x l 8255 lm vic mode 0
Trong ch 0, 8255 cho mt kh nng xut v nhp d liu n gin qua 3cng A,B,C. PA, PB, PC c s dng c lp vi nhau, 3 ng dy u c dng trao i s liu hoc thng tin v iu khin v trng thi mt cch bnh ng vinhau v tu la chn:
Tm hiu mt s linh kin6
Mode 1
A0 PA7
A0 PA7
A0 PA7
RDWR, D0 D7 A0,A1,
B C A
B0 PB7PC0 PC3 PC4 PC7
A0 PA7
Mode 0
B APC0 PC1 PC2 PC3 PC4 PC5 PC6 PC7
B0 PB7
B0 PB7INTR
B
IBF STB INTR STB IBF I/O I/O
BOBF BACK I/OI/O
AACK AOBF
Mode 2B A
B0 PB7
PC0 PC1 PC2 PC3 PC4 PC5 PC6 PC7
INTRA
STBA
AACKAOBF
IBFA
Ca vo
Ca ra
I/O ( mode 0)i thoi (mode 1)
Ca B mode 0 hoc 1 i thoi ca A
i thoi ca Ai thoi ca B
8255
PA0 PA7
PC0 PC3
PC4
PC7
PB0 PB7
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8255 lm vic mode 1L ch vo/ra c cht, tc l c s i thoi gia ngoi vi v h vi x l thng
qua cc bit PortC. C 2 nhm:Nhm A: gm PortA dng trao i s liu v na PortC cao( PC4 PC7 )
i thoi gia vi x l v ngoi vi.Nhm B: gm PortB dng trao i s liu v na PortC thp( PC0 PC3 )
i thoi gia vi x l v ngoi vi.Hng v ch 1 ca PortA, PortB do t lnh iu khin quyt nh, cc tn hiu
i thoi PCi ph thuc hng cng vo hay ra. Xut d liu ra trong mode 1
Cng PA, PB c tn hiu i thoi tng t nhau. Tn hiu OPFBOBFA, bo rngb m ra y cho ngoi vi bit CPU ghi d liu vo cng chun b a ra.Tn hiu ny thng ni vi tn hiu STR ca thit b nhn.
Tn hiu ACKBACKA, l tn hiu ca ngoi vi cho bit n nhn c d liu tcc cng PA, PB.
Tn hiu INTRA, ITRB l tn hiu yu cu ngt t PA, PB.INTEA, INTEB l tn hiu ca mt mch lt bn trong 8255 cho php hoc
cm yu cu ngt INTRA hoc INTRB ca PA hoc PB.INTEA c lp/xo thng qua bit PC6INTEB c lp/xo thng qua bit PC2Khi lm vic ch xut thng tin mode 1, thanh ghi trng thi ca 8255 cung
cp cc thng tin phn nh trng thi hin hnh ca mnhS ghp ni ca 8255 mode 1
OBFA (Output Bufer A full) Cng A c d liu ri
Tm hiu mt s linh kin7
PC6
PC3
PC1
PC2
PC0
PC7
PA0 PA7
PB0 PB7
PC4,5
INTEA
INTEB
OBFA
ACKA
OBFB
INRA
ACKB
INRB
I/O
RA
PC5
PC3
PC2
PC1
PC0
PC4
PA0 PA7
PB0 PB7
PC6,7
INTEA
INTEB
STBA
INTE
INRB
VO
IBFA
STBB
IBFB
I/O
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OBFB (Output Bufer B full) Cng B c d liu riINTEA ( Interrupt Enable For PortA) cho php PA chy ch ngt.INTEB ( Interrupt Enable For PortB) cho php PB chy ch ngt.INTRA ( Interrupt PortA ) PA ngtINTRB ( Interrupt PortB ) PB ngt
Ni dung thanh ghi trng thi ca 8255 mode 1 cho hng ra:D7 D6 D5 D4 D3 D2 D1 D0
OBFA INTEA IO IO INTRA INTEB OBFB INTRB
Nhn d liu vo trong mode 1Khi nhn d liuvo trong mode 1 cc cng PA, PB c tn hiu i thoi tng t
nhau:STB ( cho php cht d liu). Khi d liu sn sng trn knh PA, PB ngoi vi
phi dung STB bo cho 8255 bit cht d liu vo cng PA hoc PB.Sau khi 8255 cht c d liu do thit b ngoi vi a n, n a ra tn hiu IBF
(In Buffer full) bo cho ngoi vi bit.Ni dung thanh ghi trng thi ca 8255 mode 1 cho hng vo:D7 D6 D5 D4 D3 D2 D1 D0
IO IO OBFA INTEA INTRA INTEB OBFB INTRB
8255 lm vic mode 2Ch ny ch dng cho cng PA vi vo/ra 2 chiu cc bit PC3 PC7 dng
lm tn hiu i thoi.Mch logic ca 8255 mode 2 v cc tn hiu i thoi:
Tm hiu mt s linh kin8
PC3
PC7
PC6
PC5
PC4
PA0 PA7
PB0 PB7
PC0,2
ACKA
OBFA
INRA
I/O
Vo
INTE 1
INTE 2
IBFA
STBA
PC3
PC7
PC6
PC5
PC4
PA0 PA7
PB0 PB7
PC1PC2
PC0
ACKA
OBFA
INRA
Ra
INTE 1
INTE 2
IBFA
STBA
INTRB
ACKA
OBFB
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Cng PB c th lm vic mode 1 hoc mode 0 tu theo bit iu khin trongthanh ghi CWR.
INTRA: yu cu ngtcho d liu 2 chiu vo/ra.INTE 1, INTE 2: l l 2 tn hiu ca 2 mch lt bn trong 8255 cho php hoc
cm yu cu ngt ca PA, cc bit ny c lp xo bi PC6 v PC4.
Khi dng 8255 trong ch bus 2 chiu trao i d liu theo cch thm d,phi kim tra xem bit IBFA c bng 0 (m vo rng) hay khng trc khidng lnhIN nhn d liu t cng PA.
Khi lm vic ch truyn thng tin 2 chiu ca mode 2, thanh ghi trng thica 8255 cung cp cc thng tin phn nh trng thi hin hnh ca mnh.
Ni dung thanh ghi trng thi:D7 D6 D5 D4 D3 D2 D1 D0
OBFA INTE1 IBFA INTE2 INTRA x x x
Tm hiu mt s linh kin9
Nhm A Nhm B
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8254( 8253 )Mch nh thi gian lp trnh c 8254/8253 l mt mch ph rt quan trng
trong cc h vi x l ca Intel. N c th p ng c cc yu cu ng dng khcnhau trong h vi x l: m thi gian, m s kin, chia tn s, to ra dy xung
c im ca 8254/8253: Hot ng tn s cc i l 8MHz. Nh da trn cng ngh CMOS nn t c tc cao v tiu th nng lng
thp. Hot ng ch hon ton tnh. C 3 b m li ( Down- counter ) c lp 16 bit. Ngun cung cp t 3V 6V. C th m nh phn hoc thp phn. MSM82C53-2RS c 24 chn. MSM82C53-2JS c 28 chn. MSM82C53-2GS-VK c 32 chn.S khi chc nng:
Chn chn v (CS) ca vi mch 8254/8253 phi c ni vi u ra ca mt bgii m nh a ch c bn cho mch. Cng vi a ch c bn, cc chn a chA1 v A0 s cung cp cc a ch c th ca cc thanh ghi bn trong 8254/8253 khighi ( lp trnh ) hoc c thng tin ca mch. l thanh ghi cho 3 b m v mtthanh ghi cho t iu khin. Ni dung ban u ca mi b m u c th lp trnht CPU thay i c. Ngoi ra cn c th iu khin hot ng ca cc b mbng tn hiu t bn ngoi qua cc chn ca ( GATE ) cho php bt u m( GATE = 1) hay kt thc qu trnh m ( GATE = 0). Gi tr ca b m c tht bng byte hoc word.
Truyn d liu gia bus d liu( data bus ) v thanh ghi bn trong c m t bibng sau:
Tm hiu mt s linh kin10
Counter#0
Counter#1
Counter#2
Control
wordregisrer
Read/
Write logicData bus
buffer
CLK0 GATE0 OUT0 CLK1 GATE1 OUT1 OUT2GATE2CLK2
Vcc GND
D7 D0
8
RDWR A0 A1CS
8
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CS RD WR A1 A0 Chc nng
0 1 0 0 0 Counter#0 ghi d liu t data bus0 1 0 0 1 Counter#1 ghi d liu t data bus0 1 0 1 0 Counter#2 ghi d liu t data bus0 1 0 1 1 Ghi thanh ghi t iu khin
0 0 1 0 0 Data bus c d liu t counter#00 0 1 0 1 Data bus c d liu t counter#10 0 1 1 0 Data bus c d liu t counter#20 0 1 1 11 X x X x0 1 1 X x
Data bus trng thi cao tr
1. Khi u cho 8254/8253Cng nh cc vi mch lp trnh c khc ph tr cho CPU, sau khi bt in mch
8254/8253 phi c khi u c th hot ng theo ng yu cu. Mt iu cn
ch l trng thi ca 8254/8253 sau khi bt in l khng xc nh. khi u cho 8254/8253 ta phi ghi t iu khin vo thanh ghi t iu khin
ca n. Dng thc t iu khin ca 8254/8253 nh sau:
D7 D6 D5 D4 D3 D2 D1 D0SC1 SC0 RW1 RW0 M2 M1 M0 BCD
Chn b m ( select counter ) qua CS1 v CS0:
Ghi/c :RW1 RW0
0 0 Lnh cht b m
0 1 c/ghi byte c trng s nh nht(LBS)1 0 c/ghi byte c trng s ln nht(MBS)1 1 c/ghi byte LBS, tip theo l MBS
t ch :M2 M1 M00 0 0 Mode 0- to yu cu ngt khi m ht0 0 1 Mode 1- a hi i lp trnh c0 1 0 Mode 2- b chia tn s cho N0 1 1 Mode 3- to xung vung
1 0 0 Mode 4- to xung cho php mm1 0 1 Mode 5- to xung cho php cng
Tm hiu mt s linh kin11
Selectcounter
Ghi/cChn ch
SC1 SC0 Chn ra0 0 Counter#0 c chn0 1 Counter#1 c chn1 0 Counter#2 c chn1 1 Lnh c ngc
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t ch m qua bit BCD: bit BCD = 0 m nh phn 16bit, bit BCD = 1 mthp phn 4 decades.
Thanh ghi t iu khin dng cha t iu khin cho c 3 b m. Vi cc bitSC0, SC1 ta c th chn ra b m lm vic theo cch thc do t iu khin quyt
nh. Trng hp c bit khi SC1 v SC0 = 1 ta c th dng lnh c ngc c -c ni dung hoc trng thi ca b m trong thi im hin ti.Cc b m ca 8254/8253 u lm vic ch m li. Nh vy s m ln
nht m ta c th a vo b m bt u m l 10000H hoc 10000, v sau khili 1 ta c ni dung mi ca b m l FFFFH hoc 9999 tu theo bit BCD = 0 hayBCD =1.
Cc bit M2,M1,M0 s xc nh cc ch lm vic ca b m, trong ccu vo GATE c nhng tc ng khc nhau n cc u ra OUT.
Cc bit RW1,RW0 cho php chn cch thc ghi/c vi cc b m. Ta c thghi/c tch ring tng byte ca b m. Nu mun ghi/c lin tip 2 byte ca bm th ta phi tun theo th t byte thp trc v tip theo l byte cao.
2. Cc ch lm vic ca 8254/8253Mode 0 To yu cu ngt khi m xong ( terminal count) ch ny t iu khin CW= 10H, ch c/ghi LSB v ch m theo h 16
cho b m s 0. Sau khi ghi t iu khin vo thanh ghi t iu khin th OUT= 0.Tip theo ta hgi LSB = 4l phn thp ca s m cho b m. Gi tr ny s cchuyn vo b m chu k ng h sau. Lc ny GATE = 1 nn b m bt um ngc. Khi b m t ti 0 th OUT =1. iu c ngha nu ta np vo LSB =N th sau N+1 xung ng h ta c OUT = 1. sau khi t 0000H th b m tip tcm li t FFFFH nu nh n khng c np gi tr m mi. Xung OUT c th cdng nh l xung yu cu ngt i vi CPU bo l t s m ( terminalcount ).
Khi b m ang lm vic m GATE = 0 th ni dung ca b m c gi khngi cho n khi GATE = 1, lc ny b m li tip tc m li.
Khi b m ang lm vic m c xung iu khin np ni dung s mi, ni dungmi ch c a n b m ti xung ng h tip theo. Sau b m li tip tcm li vi s m mi.Mode 1- a hi i vi thi gian lp trnh c
ch ny ta c CW = 12H, ch c/ghi LSB v ch m theo h 16 cho bm 0. Sau khi ghi t iu khin vo thanh ghi t iu khin th OUT = 1. Tip theota ghi LSB = 3 l phn thp ca s m cho b m. Gi tr ny s c chuyn vo
b m. Lc ny GATE = 0 nn b m cha lm vic. Khi c xung kch GATE = 1th b m bt u lm vic chu k ng h sau. T y OUT=0 v bt u qutrnh m ngc. Khi b m t ti 0 th OUT = 1. iu c ngha l nu ta npvo LSB = N v GATE = 1 th OUT = 0 trong N xung ng h. B m sau khi t0000H th s m li t FFFFH nu nh n khng c np gi tr m mi v mi khic xung GATE = 1 n li to ra xung OUT = 0 trong N xung ng h.
Khi b m ang lm vic v cha t c s m m c xung GATE = 1 th sm c c np li cho b m chu k ng h sau. T lc ny b m li tip tcm li. OUT = 0 cho n khi m ht.
Khi b m ang hot ng m ta c xung iu khin np s m mi th ni
dung mi ch c a n b m ti xung ng h tip theo sau khi c xung GATE= 1.
Tm hiu mt s linh kin12
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Mode 2-To xung c tn s fin/N ch ny ta c CW = 14H, tc l ch c/ghi LSB v ch m theo h 16
cho b m s 0. Sau khi ghi t iu khin vo thanh ghi t iu khin th OUT = 1.tip theo ta ghi LSB = 3 l phn thp ca s m cho b m. Gi tr ny c chuynvo b m ti chu k sau ca xung ng h. Lc ny GATE= 1 nn b m bt u
lm vic. T y bt u qu trnh m ngc. Khi b m t n 1 th OUT = 0trong thi gian 1 xung ng hv qu trnh m ngc li c bt u vi OUT = 1v vi s m c. iu c ngha l khi ta np LSB=N vo b m th c sau Nxung ng h, ta c u ra OUT = 0 trong thi gian 1 xung ng h.
Khi b m ang lm vic v cha t c s m m c xung GATE = 0 th gitr hin thi ca b m c c gi nguyn trong sut thi gian GATE = 0. KhiGATE = 1 th b m li tip tc m li.
Khi b m ang hot ng v cha t s m m c xung iu khin np sm mi th b m vn tip tc vi s m c, ch ti khi b m m n 1 ths m mi mi c p dng.
Mode 3- To dy xung vung ch ny ta c CW = 16H, ch c/ghi LSB v ch m theo h 16 cho bm s 0. Sau khi ghi t iu khin vo thanh ghi t iu khin th OUT = 0. Tiptheo ta ghi LSB = 4 l phn thp ca s m cho b m. Gi tr ny s c chuynvo b m ti xung ng h sau. Lc ny GATE = 1 nn b m bt u ngay qutrnh m ngc. Khi b m t ti (4/2)=2 th OUT = 0 trongtrong thi gian (4/2)=2 xung ng h cn li v qu trnh m li c bt u vi OUT = 1 v vi sm c. iu c ngha l sau khi ta np LSB = N (s chn) vo b m th c sauN xung ng hta c OUT = 1 trong N/2 xung ng h v OUT = 0 trong N/2 xungng h. Nu N l s l th c sau N xung ng h ta c OUT = 1 trong (N+1)/2xung ng h v OUT = 0 trong (N-1)/2 xung ng h cn li.
Khi b m ang hot ng m c xung GATE = 0 th b m khng thay ini dung chng no cn c GATE = 0, khi GATE = 1 n tip tc m li t gi trhin thi.Mode 4- To xung cho php bng ch ng trnh
ch ny ta c CW = 18H, ch/c ghi LSB v ch m theo h 16 cho bm s 0. Sau khi ghi t iu khin vo thanh ghi t iu khin thi OUT = 1. Tiptheo ta ghi LSB = 3 l phn thp ca s m cho b m. Gi tr ny s c chuynvo b m ti xung ng h sau. Lc ny GATE = 1 nn b m bt u ngay qutrnh m ngc. Khi b m t ti 0 th OUT = 0 trong thi gian 1 xung ng h vqua trnh m li tip tc t FFFFH vi OUT = 1. Tc l nu ta np s m N th
sau N+1 xung ng h th ta s c c xung cho php tch cc thp ko di 1 xungng h.
Sau khi b m c np s m n vn cha lm vic chng no cha c xungGATE = 1.
Khi b m ang m v cha t s m m ta c xung iu khin np s mmi th s m mi s c np v bt u m li ti xung ng h tip ngay sau .Mode 5- To xung cho php bng xung iu khin GATE
ch ny ta c CW = 1AH, ch c/ghi LSB v ch m theo h 16 chob m s 0. Sau khi ghi t iu khin vo thanh ghi t iu khin th OUT = 1. Tiptheo ta ghi LSB = 3 l phn thp ca s m cho b m. Lc ny GATE = 0 nn b
m cha lm vic. Khi c xung kch GATE = 1 th chu k ng h sau b m btu qu trnh m ngc. Khi b m t ti 0 th OUT = 0trong thi gian mt xung
Tm hiu mt s linh kin13
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Tim boi : [email protected] Bo co thc tp tt nghip
ng h v qu trnh m li tip tc t FFFFH vi OUT = 1 nu khng c xungGATE =1 mi. Tc l nu ta np s m l N v xung GATE=1 th sau N+1 xungng h ta s c xung cho php tch cc thp ko di 1 xung ng h.
Khi b m ang m li v cha t s m c xung GATE = 1 b m c npli s m c v n bt u m li ti xung ng h tip ngay sau .
Khi c lnh np s mi b m vn tip tc m li vi s m c cho ti khinhn c xung GATE =1 th s m mi mi c p dng xung ng h sau.
Tm hiu mt s linh kin14
WR
Clk
GATE
OUT
CW=10 LSB= 4
WR
Clk
CW=10 LSB=3
GATE
OUT
WR
Clk
CW=10 LSB=3 LSB=2
GATE
OUT
Biu thi gian ca 8254/8253 mode 0
N N N 4 3 2 1 0 F F
N N 3 2 2 2 1 0 F
N N 3 2 1 2 1 0 F
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Tm hiu mt s linh kin15
GATE
GATE
GATE
WR
Clk
CW=12 LSB=3
OUT
WR
Clk
CW=12 LSB=3
OUT
WR
Clk
CW=12 LSB=2 LSB=4
OUT
Biu thi gian ca 8254/8253 mode 1
N N N N 3 2 1 0 F 3 2
N N N N 3 2 1 3 2 1 0
N N N N 2 1 0 F E 4 3
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Tm hiu mt s linh kin16
WR
Clk
CW=14 LSB=3
GATE
OUT
WR
Clk
CW=14 LSB=3
GATE
OUT
WR
Clk
CW=14 LSB=4 LSB=5
Biu thi gian ca 8254/8253 mode 2
N N N N 3 2 1 3 2 1 3
N N N N 3 2 2 3 2 1 3
GATE
OUT
N N N N 4 3 2 1 5 4 3
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Tm hiu mt s linh kin17
WR
Clk
CW=16 LSB=4
GATE
OUT
WR
Clk
CW=16 LSB=5
GATE
OUT
WR
Clk
CW=16 LSB=4
GATE
OUT
Biu thi gian ca 8254/8253 mode 3
N N N N 4 2 4 2 4 2 4 2
N N N N 4 2 0 4 2 4 2 0 4
N N N N 4 2 4 2 2 2 4 2 4
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Tm hiu mt s linh kin18
WR
Clk
CW=18 LSB=3
GATE
OUT
WR
Clk
CW=18 LSB=3
GATE
OUT
WR
Clk
CW=18 LSB=3 LSB=2
GATE
OUT
Biu thi gian ca 8254/8253 mode 4
N N N N 3 2 1 0 F E D C
N N N N 3 3 3 2 1 0 F E
N N N N 3 2 1 2 1 0 F E
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Tm hiu mt s linh kin19
WR
Clk
CW=1A LSB=3
GATE
OUT
WR
Clk
CW=1A LSB=3
GATE
OUT
WR
Clk
CW=1A LSB=3 LSB=5
GATE
OUT
Biu thi gian ca 8254/8253 mode 5
N N N N 3 2 1 0 F 3 2 1
N N N N N 3 2 3 2 1 0 F
N N N N N 3 2 1 0 F E 5 4
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7400 l IC gm 4 phn t NAND 2 u vo:S chn:
11 9 813 12 10
Vcc
14
7
GND
654321
IC7400
7402 l IC gm 4 phn t NOR 2 u vo:S chn:
1 2 3 4 5 6 7
GND
Vcc
14 101213 8911
IC7402
7404 l IC gm 6 phn t NO :
S chn:
1 2 3 4 5 6 7
GND
Vcc
14 13 12 11 10 9 8
IC7404
7432 l IC gm 4 phn t OR 2 u vo:S chn:
1 2 3 4 5 6 7
GND
Vcc
14 13 12 11 10 9 8
IC7432
Tm hiu mt s linh kin20
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74LS138 l mch gii m:S chn:
8GND
Vcc16
Y015
Y114
Y312
Y69
Y510
Y411
7Y7
6G1
5G2B
4G2A
3C
2B
1A
Y213
74LS138
Bng chc nng ca 74LS138:Cc u vo
Chn Cho phpCc u ra
C B A BG2 AG2 G1 0Y 1Y 2Y 3Y 4Y 5Y 6Y 7YX x x 1 x x 1 1 1 1 1 1 1 1X x x x 1 x 1 1 1 1 1 1 1 1X x x x x 0 1 1 1 1 1 1 1 10 0 0 0 0 1 0 1 1 1 1 1 1 10 0 1 0 0 1 1 0 1 1 1 1 1 10 1 0 0 0 1 1 1 0 1 1 1 1 10 1 1 0 0 1 1 1 1 0 1 1 1 11 0 0 0 0 1 1 1 1 1 0 1 1 11 0 1 0 0 1 1 1 1 1 1 0 1 1
1 1 0 0 0 1 1 1 1 1 1 1 0 11 1 1 0 0 1 1 1 1 1 1 1 1 0
74273 l IC gm 8 D FF ng b theo sn xung, mch ra 3 trng thi:S chn:
Clock5Q5D6D6Q7D8D8QVcc
GND4Q4D3Q3D2Q2D1D1Qclear
7Q
74273
Bng chc nng:
Clear Clock D Output(Q)L x x L
H H HH L LH L x Q0
Tm hiu mt s linh kin21
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S chn ca 373:
7Q
1Q 1D2D2Q 3D3Q4D4Q GND
Vcc8Q8D7D 6Q6D5D5Q
OutputControl
G
373
Bng chc nng ca 373:
Output Control G D Output(Q)L H H HL H L L
L L x Q0H x x T
H: Mc High, L: Mc Low, T: Ba trng thi, Q0: D liu c lu nhADC0808, ADC0809. L b chuyn i tng t s 8 bits, 8 knh u vo, u ra
3 trng thi.c im:
phn gii 8 bits. Ngun cung cp n 5V. 8 knh u vo.
Cng sut tiu th: 15mW. u ra 3 trng thi. in p u vo tng t 0V 5V.
Cc u ra nh s t 2-8 2-1.Cc u chn a ch: A, B, C.S chn:
IN228
IN127
IN026
A25
B24
C23
ALE22 2021 191817 15
REF(-)16
1IN3
2IN4
3IN5
4IN65IN76
START7
EDC8 9OutputEnable
10Clock11Vcc12
REF(+)13GND14
ADC0808
ADC0809
2-1 2-2
2-3 2-4 2-5
2-8 2-7
Tm hiu mt s linh kin22
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Chn knh vou chn a ch
C B AIN0 L L LIN1 L L H
IN2 L H LIN3 L H HIN4 H L LIN5 H L HIN6 H H LIN7 H H H
DAC0808. L b bin i s tng t 8 bits.c im:
Kh chnh xc: sai s 0.19%.
Cng vo khng o, giao tip c vi TTL v CMOS. Gii in p cung cp 4.5V 18V. Cng sut 33mW ( 5V).
Cc gi tr danh nh: in p ngun:
Vcc +18VVEE - 18V
in p u vo s: 10V +18V. in p ra: -11V +18V Dng chun: 5mA. Cng sut tiu tn theo v: 1000mW
S chn:
1
2
3
4
5
6
15
14
12
11
10
9
I0
A4A5
A6
VREF(+)
VREF(-)
7
8
13
16COMPENSATION
Vcc
A8
A7
A3
A2
A1
VEE
NC
GND
DAC0808
Tm hiu mt s linh kin23
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245 Thng dng lm b khuych i mS chn:
c im: Giao din bus 2 chiu. u ra 3 trng thi.
S chc nng:
Bng chc nng:
Inputs Inputs/outputs
OE DIR An BnL L A = B Inputs
L H Inputs B = AH x Z ZZ - trng thi cao tr.
24
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