同步二进制记数器.ewb

EWB经典实用列子

>0GH8D>DM4CDD4M<28346D44LHBHC8:4@49D8@>H1HE4HD1@:<KD9@1D3464H<>H6
HD4M@B0C@20><=0K@:L@<4H68O<ML;06@NH0LO@0<$000@J8@0@004D8@4082040N
D>04LADC@68;LJ8B004A4MDL8LH1DK4HHH004240@@@A030648@J87H?D?4C@9@=4
BLGD<@7H>0KHI@ED283D6@80K000440<8@IDFH<@B8EDLHB@74E<GD>0@0I0;4EHK
<A8:4B<=@6HLH1DC<6L>DL@L87D1888EH5H2<6D<8@0C0A4L@58C47<=L4HD@KD48
2<<8=HG404F8<@J4I@2@HD5D6HBL849DI<F0ID:H<8J0@@F8O<<H88IH?D68NL7<4
H8HB8OD<8L@K@8H64=@88;4:H6<<088IH:D6<?<L4B0JDI@6H<L>8BD2L9H107<80
0H9HA074F05@I400840<4HD8I@L<5H386<:<F0@0AH4@D4M@80C0DD10O00L$000@
38500004:81L>0KHI@04B48H0L1D207080I@M@A404D80H90D8JDC@68<LJ<9<LHG
D=H<8O8A@?4H<LH9D3DG41D0404B<=@>84LADC@68;LJ8B0HD>L>4N<@H=@<<L0@0
100888H@1@3048=4CLGH7@9HDHF@I<;H68;L>H9<IH:<B<<42<2LDDG0FDB4ND2<D
<LHEHD8;4CL8D544HF@3D202<<81HK@B<BD8D2<J4@44D8H0HA0C<>490I@8L6DOL
NHK0@@F06<<@K@@@C86<4<H43D2@2<B4FD>L6L4H=@E0G42H=85@2DL<LH@@:0H<L
H:<6@;4AL=L6<4<@LC8G<=L0H9H7D@<EHG@>8MH6<C8A01HA4046<MHG834>LMLM@
CD044<<LC0GDLDHHH@B014HH1H;L2@6D<420LDN@I<D80@O@0<$000@<8@0O@:00<
8@0<0D4080M8<4I@3<6H=LM8I004B40H0@9@F8I4CD6@>8I8?@948<2HKLHDID3<F
8AD@40<4810102468=HA0D@?DO8N870C4J85H?<I4?@L0G@C4;<4D78=0@0B0;4C4
7D64=HFH9LNHC8:<LH=@C8HD=@<0ODIDG@<@DH7D74G<>0M8544HDH70=078G<I@H
@I0A4A<B<>0:HI@O8A@<D=HK0O@B@F<7DC@?8A8242<A@CD6DF<FL1@I@8@>82HIH
KD7DJ<MLO@6HA<3<1DC040ID=0644<@HC<>0A0<4<H30H<<HODFL@88<<HM06LDL3
06@H4K0;46<9<7DD810L<20C424049D9@O040M45834409DO0A0EHB834G@M@G414
1LI@0@O@0<$000@80@0I@L49H3874<DGHD@440<481D1030403850J@CH7D=HKHB0
=D1@3@208480A0@044B8FHM4I<L<L@94G<M@4DF<@4N<<H=H2DM0D00488<H>LLDJ
@=@<<4HK4=<9HC4F<=4<HF<7H?<3<2L0<0@IH?8=DDD4H;4<0I@3<6H=LM8I0HD?<
308HJLHDA0147DNLBL1H3474>4>4A8O<9<3HIH@HLD@@F0=<444LBLC8>4I<IDDLE
0>8A434G4H@D0;46H>08H@8J0>DH09@I0I4DLLHKH5D>D6@243D;0L8>8HH:D6HK<
;@L@:0<H;DM0G47LI8E4:42<0H0LK@A@0<=8@8FD0<=HHH@4>090044L907820N01
L$000@80M@04J4800410B0?8@0N<<H1HA06@78=0@0B0>40<H@1@2074?L28EDLHB
@74C<;H6H80L00024D<<H>L1L1DC0>D0DH88H9DF8H@C06L=@KHJ@B4;<2L40<0B8
9DMHD@B4:<LH9<38F8O05H=HKHB0=D1@3@208480A0C0248<4@MDJ<BLHLI4B@>H8
D>D00IH?0N84<A80<ML;DJ@MD00C420>HBDA@C820><JDI@I8M@E4A4M058C<G<58
<H=@4@6<<<50I<144HJ@K@;H8H5<@L4HE8M<<@IH:86<D4M@2HC4:0<<GLC4<4EL3
46<B4LDG8=<9<O@E@;<6H;<B4A4H49DI074404LN@3@406<N8HDB0E07000LLEHD4
>4><0LL@G@?<7H6HH4;0C8M89D6@94H@1@N4IL@@6<>H5<6064?H0DO@0<$000@HH
G@<4N<DHAH3@20=480H000J4800410B0?8G0B<8H9HC45L=4I0L8G<G0?48<FH64>
0800@0444<88H1@B4F@9L;L3H4L:<K8<D5LC41LC@6L><E<8@0L1D206<<H@0B0K4
0H9D;@3@><I8C@9DN<HHHDM@D4A4=41@6DNLI0I0146DNLJ@K@=L6D=@7H8D>4=L4
<9<A@I@;D;DML<D><<LJ00@<<0LI0A@K@J4<@2@F<M44D00<L3@2<6<AHF4K43H9H
7DHDB014GHIHAH>@L4B0JHI@G0M84H;09<K<CHE4A4505DC<HH:<9<1<DHJL<0M@H
@606D68B<L40084L<<HN09HHHID;00H<HC@3<E028D<4H0@CD1DO00L$000@I0B@O
4080L8@202048<@L@2004D8@4082040><M0I<D<7<=4L@B@DD;DNHJ8><1LC@6L><
80D@J4840<0@1D3040<@@0C0@4F<C<M@6DDLI@;4=D2HF<GHML:HD<4HK4=<I@3<6
H=LM8I0ED3L2060I4DH14LD9<38F8O05H=HKHF8E<<8K@@@C8E<I<B0I@G05L4HB8
E<=@KHL@<H;@CD=H64=@88H8?D68B4KD:L2<=8MHC<G4IL=8D8G<GL;@H@A@C0=85
H8DA@BL444LG<C4J0><KDI@902<2<4L<D4DC@4DE0LH6HC8A4<4;0B0>@2L9DBD6D
C8G<<@8HJHB04H0@C4J0><ED<DA4HHA8B4HDI@I0D84HD@<D1474>L0LO4<L9D1@7
8K8KD@0?L$000@J8M0F00448<H9LA@3<40>0@0B0440<0H103840;<=4D0000@907
DA@?4H<LH9D3D7440J8@0@0946HG4B<8H9HC45L=4I0L8G<G0?48<FH64>0800@04
4448HH1@B4F@9L;L3H4L:<K8<D5LC41LC@6L><E<8@<L;4D8;4HH<HFH842<2LHLC
@68<LFD?4H<<8J@K@6470=888K4;D68D4LHEH3@40<@HH@4=0MH=H?@94E8A4M41<
AHEHKDGLG<DH4HF85@>L24I@G03<I8F8B0242<=8MH5HJ<BD3D1LD8G018LLH@246
<MHG<>4N<>H68>8J@?@6DH<4HD8:<EL18<HB83@F48L8@6@54K0K@6D6H<<@4C02H
;8C@FL84B874<8@H74>84898?0I42HCLC8@4K<J0@@G<@0?L$000@I8?@@40<4810
102464<@A000J4800410B074N@LDJ4CD6@>8I8J85H?<M4G40LIHC<7440J8M0D00
4D88H1D206080I@H004484HK4=<9HC4F<=44H0<<@D<<@J@4@O<A@?4H<LH9D3DG4
1D7D8LD8=488O0B8@H5@GHA<C<6L<@K46D6LD4LLK8B86<@<4H1@EHD414<DJLI0I
0147DJLI0A@J8<@48G4FH7H3<6DF<K@=L9<:0BH<DILA@C<KDA0F8B014>4;4L0@@
C8=<=@CH3@9D70A0004LD@BD1H74H@F434>DH8H49H74D4ILIH20>@>LC4D4140D>
H0HO@0<$000@KHJ@B40<481D10304038500004:81L>LJ8I054N<4D1D;4?@2L6L=
LI06H0H1HA040408@H@C044B8NHM4E<<<K44@>46<@LIHB@68>@M0D@>4><<HEHB@
K09<9<6DE4H<FH049DM<DLA@;@K8B8=0?HO<L<KL2L68I4BHBD0D@L983HG010;DE
@@@<4:<FL=4>8>@J00024N<0<1@2L60F<4DK89D34;<OL<LM4>H6<FL48B4:D;L3H
34E4L<<HI@B468=H<4N8I@9@F8HDBD60>H74G@C8BD2L0<4H9H6D:<N8F@=4;<M0I
4I4?<3H5D64CHE4L84H1DCDG4?<8H4HF84LCHI@34B<@H1DC<FLMDG@KDO@A0KH@4
N86HG4K4E@I0F86@><CL@0=@1<4HIHF0E8JD:@A0@4N<JHHD5@HH9D=L946LDDJ4:
<2HHLCHJ@<L88<<9@8@CL20148<4LM@>4H@E034=<GL7@H830KDG8F@:L?DB@2H6@
B448G8N88H1H;4308@0@FDH8ILJ08@=L=@NL60;43878=41<8D7@D4IH<D=4K@G89
<AH3@74I4GHJ@BLJ@4H6DD<9D>D7DD4;@;8@HA8C@78>@J0:0144<@H5DF8AH@@G@
?4H<DH103H70>8@<N80@A89L=L<4LHE@8DBH0HB<6L<LJ8A@14G8E<N8M08D8L84>
<H<;@G<G4<@I0A0=4O8HDD0IL206H=LHHE@2DD8HLM0B82DG@DLN0L0HD3H64EH0H
@4F8@0?L$000@80@0I@<410C<6D><D0B@B48<4@AD3D20=480H000J480D4FHM4E<
<<K4;@94L<@HI@C<7<94K@C0?45<0DNHJ888:0KHI@948<4LID3<FLJDD<4<0HID2
<C004888H1H206H<HI0=@84HH1D205D=HH@=@?H3<6H;<B4440<<HH<<8K@?@K8K<
?87DJ0O@BHD<<H3L90;@G0LD<L1HKD4<8@14L@I4C@64=4K0F0=DH0C06L>0I83HJ
09@9DB@6<ML=4:8@L=DM4=<:8@H=HL4MH=H643<48@<4HK4MHI83<74<@AHB@>4M<
;H74F47464?4><4HIDC040=HH8F0I4D<:L68HL2LD048DL1H3D6@:@H8A0<4E<7HC
8A4MD4HL@1D;4MD@<F<>46<I47H8HM8G034I<?HF0A4ID28HD;864<0JH2L9@0@5D
K<2D><J8I@F4K8:HCDF8905860N8DHAHC@F@K<B0OL8@<LO<A<A@2474<DL8@0E@M
L180DB<<094D8:<2D6L=4M0:H;8;8J8DD7D9HM8F@84288H9HK<G<L@4@G<;05D?L
>@DHA@143<CDB<6@7HD<D0146<DL9@JD5HF8O07H9@J8G054><8@9H3070=0J4?87
4ADF8@84824LL0H3<28:H1@AL=8@854>@9<0@;D6H4<<8;LFH7H4HN@O8?00<BLN<
50F<484H<8=<IH<H4HDHJLCD68<DL0:0I40<2L84@LE<9H9@34G46D;8CLBH649HF
@30@DL88@G41H146<<8ID?490=4N@480@98:D908L8@J8I@5D0H>81DNDH48@ID@0
?L$000@80I00424D<I@A83060806@:00008D@3HDHJ0?40<HLA0C@68>4E8G0948<
<L1HA06@40<H<8?8KD54:<0H1HBD7@>0I8KH2LB<@LB<78=DH@B@B4;<D<NDC43@5
<3<J<I<=80<M09@342<@H=DN8A094NH6428L<A4KD0H34B4:4<D9H34F8O0L@G4ND
=H@<L4484L4HC@6L<@I8I@4D?L?<I4NL=H9<D<2LH48D?D?49DHLJDB@FH=@J8A8C
00@A<:0K0<83<7D8LDDA0?D;4ADA0980L<L149D?4:<8LIHK08H0@HD4HG@B8N45D
D@B@64A<JH0D=8A4@<G83LI<;8K<@84D5L38?LL<O84<O0;4G<3@54L<FH;HH82H4
@>8>4:4:<84@0;89L<4K8B@D4?<D8J454E8801D?4J<0HIHK<E8>08<2LH4LDC@6D
@89<J<JLG@3<E88@=0:@H@1D;4H@6H94K@A@B4A<<L=49DJLEHHDN<5LB8@8A01@1
4L<4H1@C<7@><J848J00D2D5484C@B8ED64N40D@D4<ILF8LHFHF4M<L0143@78=4
1<;0;0:0D<98B8D4<L4D2<A<G@J424BD6@=DI8L8ADE80@I4AD;@H0@0A4N4N@OHG
@>49034H<D@@0?L$000@80@0B@0<BD6@=DI880?4B<HH1DCD7440J8@0A0040<0HA
00H18=4=L6LC<88DL1@3@20>83<:@DH0DA@C8G0<H9DH8L09DEL58><I8B07D=<=@
HHJ87<O4L8O80@E48<LL=D38IDBD;@64KDO828E<408<KHH0D4B<LHADC<G4<@G<G
DG0@@E<48A@3@788HL@B@A4A<284@MD:@HD9D;8C<2@M<LHO8EHJ0C@9LC42D64B4
C<><:H6<F4KDMHB@5D68:@N8H054A<28A4B<78=DH@B@B4=<2<D<94HD=8@<M09@3
42<@H9D;430>@908L:@L@@@5DN0I@JHBHB478=HHH8HOLF@708H<L94K@9@?4:<8L
IHK0I814A8N<A8BD6L=@1<C0F<10<470?48<2HD4B0B@68<HJ4G87@E48<2L5D;8M
84HE02DD@A@JH28N42HJDAD945H547HODN@70A8JH8<54;8ALDD>0;<=8=014B4:<
HH1D;DG@@04D>40<FLI04@=40<DL1@C460=HHH48N0N84H@DDLC<B46@=HI0HH7@>
<N404DL=LA@ADK890I03<78=0>4=DE448DHBH@074=4M0D@F4K<BL2L:DE4<0H<@D
7D8@@H4850LL=D84NHHH=DB@A@5DA@@<B4@0?L$000@806@:00008D@3HDHJ0144<
@LAH2474<DL8:@>4B<@HIH3@20=480H0H@6D?<0<6LGD80I00424D<I@A8C0A0ED7
4C<C4C0;H>LI8B@@48<4D1LC@F8O0L@C@J@=44<DHA@K@38EDILL@;0K4C0;H:H3<
80<LI8C060=@B<8L9@K8DL5LALC8G@>4;<:<8<A<2DC<FLF@JL;HB@C0CHC0B4:8H
L=DD8B894FHD8N8FHJ8L@@@>46<FH882H1H6D641H5D?H<@N4MH4<B8<H1H3D74=4
H@J@D4B<FHC@48K0M81DK4=810A8ED;HA8K@2HF<7@><J848I0@DA8B@409HI4JH@
@JD?<@8H8B4LLAH=@9@K4@8L414K@O0=D5HK438<<K@CH5894@HL81D50M@844D9D
K<30282<E4>85<6L>8040<4HHHJ<O<N<HHL4F<58><:4F@E@IDD0G@94L<@H5H28:
L2<74C<>H;8H0H@A0>HEH18@<2LAH;0DD>LN8HDND14:8FL;0C8>H4D:L9@>L98CL
B4KD;<O0:@9LJ43H4D90G0B0305HD@@H1DI4<484?84@0@H@6D8L8H8@J8O0>@8@D
D9@K<18404L1@CDG8DDK<<4D<H8I<2@FD64FL@8A@C<O08H8DK@B0HDF@0DO@0<$0
00@80@0M@D4:8DH1DC@4@=HHHI004K42<0<8@0<@D=4I4=DDHK@54:<0H1HA06@40
<0B8?DC@G@44:<0H8@:0;@1<488<H8G014H<4HILC@6@><ELAD9<8<9820DL<@=<9
@3H8464?4<838:4B4K<H0HHB@>48<LL143@78=4KHFH9@FHK89<GH?<E84@34?8:H
68>47DDHJ0144<@L1HBD6@=DI8=H>49@D@M4N@0H5H6L>8040<4HHHE4O<N<HHND;
0:0:DC4:<@H5@KHN<K81@I8C<F@4DJ<<H@<A4J@7@748L<H<D;8H0E0A4=<JH4@1@
;H70<8BDKH?004;D7D>DA<<D38IDBD;@64KDO8<8<@NL2H7HJD;<:<8HL@B@A4A<2
84@MD:@HD9D38G81008EL98LH?@I8E@A0A4K@C@F<C8A4MD3HM8D<B80L9H;4B@90
C@J@=44<DHA@;@C<K0:8HD6DF<K82078:<HH@@<4:<2H0HL<J<64DD>4;82DD<:<4
@;8@@@4OHL4D4>L?0M03<3H?8@H@L?H<4D4:L<@O8@@A43H0<H4L4<4A06@?8240@
349428:LKHI0C48<<L90K018CLE8@0?L$000@80@0O@F00L8@0<@D3H?LD0N8@H9D
3474<4K@A@540<881HA0C8<@3L4L=LI06H541010C0<@A<D4>DH@4H1@KDHHD@HD>
DD4@88H9HC474=03<8@NH0@<8B8?DA01@EDC060=@N8I@946<2LCL84:0;038GD@4
8<4LID3<6L><I4CH308LNL9@D42<8H1H3DD<LD5@5H7H=@F8:<2D6L=4M0488@C@N
H2DC8N<54F<484H>8><IH=84HFHK<CD68<DL0:0I40<2L84GL5<D89H3<64<DL@:H
=L?D4LJLA8H@>HF<K84078:<HH2HB@I42LL<E@GHG@BHF4=@AHI0140<0L=D5D4D>
4<<LHED2@4L>@6D0DIDC<7<=H94KL9<2H:<J8F@E47<1L5H@LDL70O42834J44D;4
1@@H9<H8E<FDJ<DHI@BLG4K<K0K8=<040<4LMD2@8H=@D<=<:8K<H@B094K<A@84>
<BH=08<B<=0;<2HM@CHD<D@A@1464CD=43<C40@14B454<<4H=@E0C4:0>H78I@8D
M0C0D0=<1H0H1@C08@A@>LG4A<J@LD9@C<6@=H:4C@0H4LAD3D74<D7494D8NH=D1
4A<289@484L9@3<G0:444IHC<LLELFDF494I0C4@<DHAH3<G888EH@@1L1<A8FH64
B8A@C<8@0L6L=LK8L87<I0JD10A41H>HK@:8ILH4F094J@=42<0HEL6@4D<@8<JLB
0L@A<KDK8ALIL<HG04@78A43DN@?@>4:<DLID2L70=LJ8G0D4A<@08L<4M8BHELEL
AH:4N02@N01L$000@80@0O@80DL9D307@;LI8G0144<0H8@382060806@:0M0DHAD
@4N<4HAD3<78><ML240<4HJ4DD9HC8F4>LB094?L<@J8I@@4H<4H9@CH5L=LL0J0L
D4@<8J8<H>0L@B@O4888L9HC86<<LI8I0HD4L;<L4LHJ0HDFH4H?8G4?4;<34<4K0
J0JDHHF@I<C06L=HM@F094J<4H1D;D;@BL6L>DE<M8ADC45L=DI8F@?44<4L5LIHN
H2DE@9@30F84DGDEDF05D48G0<@=@:490;<K4G05H<HE<=L=@6410682@BL@HKHJ8
NLLH9<38FL<DMLM<?H4<A<:D?<E4EHMDH<@0?<7L68<DN0KHA<4HMD;DO<6D;L:H1
L2484<H<4K@2H=8;LH82HEDFLG0D@1<@878><E<5@=@L@8L6H2HC<6<FHO0B@>4A<
FD;0;014=D5HIH4H=HM8F@O4A8I8EDM0ND4<AD60<8=D:L2@DH9L=LL@9H<LK8BH;
LC86HJ4FH<0<42<2<MLK<;<I0G@8D9D;@0LC8D4GHC8C01H6HF4149L=0<DM@J0AD
9@B4O@9DN@9HE830=8GDF<:05D=8EH4@;448L@48@L5@1H3DL@I@84:<HL5D38@HI
DB46<2H9D5L<4HHA@HDL8@<C0G@LD<H5HCH<LKH7@@4B<:@?D9H:8@0C@7@:@KH1@
?4J<FH>HCD40E4I068:0LHM@J@:LDH943478=0KHB04D:<M8C<MDJ<GL@0?L$!4bf
478c1