Điện Tử - Cơ Sở Thiết Kế Mạch - Design Trên Máy Tính (Phân 2) part 5 doc

Dtle t,i thea vi tri : m6i philn tti nll~n gi,\ tri ella cluing trong bicu thue then trM tt!.. nhu tren tru phcp gan eu6i : type CoIOl'_list is Red, Orange.. ta e the' kh6ng can thiet t

Dtle t,i thea vi tri : m6i philn tti nll~n gi,\ tri ella cluing trong bicu thue then trM tt!

vr ell.) nhu tren tru phcp gan eu6i :

type CoIOl'_list is ( Red, Orange nIue White );

type Colocarray is array (CoJoclist)

of BlT_ VECTOR ( 1 downto 0);

variable X ; Coiocarray;

X ;= ( "00" "10" , "0 I" , "11" );

K hi gan giii tf! eho nhom ta e() the' kh6ng can thiet (t~lt gia trj eho tAl dl

de ph:in tu ella nhom

Vi dl,l

subtype BV7 is I3IT _ VEcrOR ( 7 duwntu 0 );

variable X : BV7;

X:= ('0' '0' '0' 'I' 'I' 'I' 'I' '1');

X '.= ( '0' '0' '0' others => '1' );

X := llvT ( '0' • '0' '0' others => 'I' ):

g, Cae hien thue djnh kieu

Oie bieu thuc djnh kicu la !lhiing bi2u thue hO(IC nh6m ciLlIlg de xac djnh

fa nilling tlnh tr'.U1g m~lp mo Vi d!.J nhu trong truong hQ'p hai beu li¢t k6 co nhling gia tfj li¢t ke gi6ng nhau CU phapcua bieu thCre dinh kieu nhu sau:

hi/If flll(e phili co kieu trung vai fl'J/):.ii;'If

170

VI dl,l tmng truang hqp hai li¢t kc co nhOng gia tri giong nhau

type Color{ is ( Red Orange, Yellmv, Green, Blue Purple);

type Color2 is ( Green, Black White Yellow);

variahle X: CaIOl·I;

X ::::: Color!' ( Yellow);

Uia tri 'YeUO\v' dU(jc XdC djnh tuong minh la thut)c kicu Colorl Nhu v(ty phcp gall (r2n lit dung \'6i cu phap

h Phcp ehuycn dui kicu

Phep ehuycn u61 kicu cung dip phuong ti¢n biC'n (k~i gia tq ella nht1ng doi tU<;l'ng Ihw>e nhGng kieu e6 quan h~ eh~t ehe voi nhau \'i dy nille kieu rca I

va kieu intej:!,cr CU ph,ip ella ph~p bien doi kieu nhu "au:

VI tiy,

signal X: STD_LOGIC_ VELIOR ( ~ downto 0);

signal Y: STD_ULOUIC YECrOR ( 3 down to 0):

Y <= STD_ULOGIC YECroR ( X ):

~6.5 Cae e:lu true tmln t~

Trang ngon ngfr VIIDL, kie'n true Xil.c djnh eh6e nfmg ella timc the: Trong kicn true chua ph[in khai IXlo cae ki~u, d.e I[n hi2u cae htll1g dc thanh ph[in va de chlfo'ng trinh con 111(.:0 sau phAn khili bao li\ eAc C{lll Irllc tlu.re hi¢n dong thoi Cic eau true thlfe bi~n dong thai co the: iit de bi0u tbue gall tin hi~u song song de khoi \'a cae !<;nh kll{1i tao phien ban cUJ Ihanh phfin Cae I~nh thy"e hi~n dong thai dU~1e ket noi veti nhau hang nhG'ng I[n hi~u Moi khoi ICnh tiwc hi~n dong thai trong mt)t kit'n true xac dinh In91 don yj t[nh toan baD gOIl1 de thao t,le tfnh toan nhu: dQe tin hi¢u \,ao tlwc

hi~1l de tfnh toan trcn cue lin hi~u do va gan nhnng gia Iri tfnh dUQ'C cho de tin hi~u ra

Trang ngon ngt1 VHDL, I1H?t cau true thy"e hi~n d6ng thoi II qua trlnh ( pruees " ) Qua tdnh Iii lTIt)t du true quan trQng dV(je su tlL.IIl); de m6 1:1

hill1h vi hOi 11 dong cua mi LCh Trong ITIQI kien lr(lc, 1[\1 ci dc qu,\ trlnh sl' dW1C Ih~rc hi¢n d6ng thai khi ma phung

\11)1 qu,\ trlnh duC)'c xay dl!ng tll" nhl1ng cfiu Ink lu,"in IV - hay 6lJl ~t)i Iii c,le \¢nh tufin tlr Trong thoi gian ITIO phlmg, cac \~nh IU(1Il IV Irong ]lll)1 qll'.\ trinh sc ctuae tlll.rc hi¢n \fill IUQ1 trong 1l1(1\ chu trinh VO \wn hM dfill Ill" I~nh thCr nh:it (k"n 10:nh lhu /I va sau do vi¢c thvc hi~n qua trlnh 1<.li quay In)" t.li knh cti.lu Vi¢c Ilwc hi~n Il1Ql qua Irlnh trong qu,i trlnh m6 phlmg In~n ngon ngiJ VHDL hi dung h.li khi gZtp diu l~nh wait va duC)'c kfeh hoat I'-.Ii khi c() su thay cit), tn.Lng thai eua it nh[it tnQt trong cac tin hi~u mCuTI Irong danh sitch

die till hi¢u I(IC d(mg

Cac I¢nh ttHIn IV trang ngon ngCr VIIDL gum eo:

Gill \¢nh gan eho hien;

Gill I¢nh gan cho lin hi¢u;

Cau I¢nh iF;

Gill 1¢1111 case;

Gill I~nh rcng null:

Cic I¢nh \'()ng \(tp

1 Phcp gan bien

Trang ngon ngu: VIIDL, phep gan bien co lac d~lllg \u"lmg II! phcp gan () cae ngon ngil" 1(lp Irlnh truyen thong Phcp g • in bien IhleL \(\p g[,\ tr! m6"i cho hilYn Cu ph<lp cua phep gan bien nhu sau:

bit';11 := hilll tllli't":

Ve" tnti eua phep gan phil! la bien da dUQ'c khai bilo tir truac Ve ph,ii ella

phcp gan Ia bieu thuc De phcp gan co the tlwc hi¢n duqc, bieu thuc d \'C trai

va bien ave pil,ii clLa phep gan phai cung ki6u,

Klli mc)t bien dU"qc gan gia II'" phcp gan duqc Ihl:re hi¢11 vl:ii tl1(\i gLan rno

phimg bimg khong DieLl d6 e6 nghia IiI sl! Ihay do, gia tri cua bien ctuqc xu)'

ra ttk Iho-i ngay t:'.li thui diem rna ph6ng hi¢n tai

Cac hic'n chi dU"<;1c khai bao trong cae gu ! trlnh ho<:tc ChU0Jlg trlnh con va

duC)'c slr cl~l!1g de Iuu tnl cac ket qua trung gian M¢t bien dU"q'c khai [)iio hl':n trung m(ll qua tdnh hO(lc chuang trlnh con se ton t~li C~IC bl) lrang qua trlnh ho~tc chuong lrlnh con do va kh6ng the dU"<;1C truy C~tP 16i Ilr cae e~iu truc :->ong song kh "ic

172

VI dV ph{;p gan bien,

suht."pe Intl6 is integcr rallj!;c 0 to 05635;

siglwl S1 S2; In116:

si~nal (iT: boolean:

pruccss (Sl, S2)

variable A, 13 : Int16:

COllstant C: Intlo;= 100;

bcgin

A :~Sl + I:

B :~ 52 *2 -C:

GT <= A > 13;

end pl'ocess;

2 Phep gall tin hieu

Trong ngon ngi::i' V HDL tin hi¢u lA m9t d~ng clui tuVng d[\c bi¢t Ph{;p gan tin hi~u dung de tbay doi gia tri eua tin hi¢u Die tin hi¢u lu6n c1uo'C bi~u dicn kc't hQ'p v6i dicn biC:n thui gian Phcp gan tin hi¢u thay doi gi{\ II'! clla lin

hi~u tl(ang lrng thea thui gian va plw thu<)e vao de mo hlnh qua Irlllh Ire Irong d.e phfin Ill' mi leh Khi tin hi¢u citlqe gan gia Ir! gia Ir! m6i clo kh(ing dWK g.an \"()'j 1111 hl~U m()\ deh IU."C Ih,1i mil plliii sau 11191 thoi gian duq'c d~nh Ijeh lrlnh trude trong Iho'i diel1l m6 ph6ng tiep then wang lWg v6i 1110 hlnh tre Phep gall lin hi~u eo eu ph{lp nhLf sau:

fJ/c"II_lfllk xJc djnh dlc gia tri gall Kieu clla bu;'u_,IIII"c ph"li trung \'6'j ki~ll ella 1{/I)li~;II_,1fc"

IfuJi_Ulal/ iii bieu thlIe C() kieu TIME

Trang 1119t qu,i trinh, vi¢c gan gia Iri clla bi~u thu'c cho tin hi~u sc throc lam tre khi chu trinh mo ph6ng diUlg thlfc hl~n va dUQ"c kiem soit bo-i loan Ilr wait Chlmg ta hay xct VI d~l ve phep gan tin hi~u trang dOi-.U1 chuC1ng I["[nh sau:

proccss

hc~in

end;

S 1 <::::: nut eLK after 30 ns ;

Sl <= DIn aftcr 0 ns ; S3<=SllmdS2;

wait on eLK;

Trang doc.lrl chuang Irinh nay Ihao tac g.ln kc'l qua c.:ua phcp tO<Ill "not eLK" cho bien SI 'iC chI9c I1wc hi91l ~au 30 ns tlnh IU tho'j di~m Illt) phong hien lai Trong Call \¢nh Ihtt hai thai gian tre clli.l phcp g<.in dU"(fc clio Ix\ng '0', khi do

n¢c gtlll gi,i Iri ella lin hi¢u DIn cho tin hi¢u S2 s0 du"(1C tln.!"c hi¢li sau khaang thi:1i gian delta tlnh III th(:ji diem m6 phc'mg hl~n t'.lI Tm111g !L.r nlllr v;ly t!"ong ph 'p g.,in lIn hieu 1\111 ta kct qu<.i ella phc'p tOiln IC)gic and \11lK hi¢n Ir0n cac gia tri hi¢n tho'i cua lill hi¢u SI d S2 Sl: dlf0c gan cho tin hi¢u

Sl S,tU khming tho'j ginn delta tinh IV Ihui diem 1116 ph()ng hi¢n Ih('ii Khi XU<lt hi¢n st! ki~n tren dU'ung lin hi¢u eLK ( gi,i tri tn~n duang tin hi9u eLK chuycn tLr '0' sang 'I' ), tat d cac giaa d~ch <.tJ dU(Jc dillh lich trlnh Inf(k thai di6m Xuflt hi~n slf ki¢n sc dUQ"c tlwc hi¢n b6i h0 m() ph()ng

Khi tin hl¢U dl:qc gan gi,,\, Ir! trang qua trinh, phcp g{m s2 :.;.{tC dinh m6t h<,1 dieu khien lin hi¢ll Trang me)t qua trinh, I110t tIll hl~U chi co the' nl 1n01

clicll khien, dicu d6 co nghlu Ib ben {rang lllQt qua trlnh tin hi~Ll chi e6 Ih~ xu[it phat til me>1 ngu()ll Neu tin hi~u dU<;1c gan gi{1 II"! trong nhicu qua tl"lnh h;lc !lhau, cllling ta 1161 l"t'ing tin hi~u c6 nhi6u dieu khi~ll Trong ng{)n ngu' VIIDL, lrong true\ng lWp m()t lin hi¢u c6 nhicu dicu klllen, cae h~l1n lJu),ct d~nh duc.K xily dl;rng c1~ xac d!llh gia tri cae tin hl~U eo llhiC:u cilCLl khic;n J"\hu' (1;1 de e<\p ltii Irong c!lll"ong ha, Irong lhl~1 ! c' m'lch ChLlllg la ph~11l bi~1 bai h<li d:'.l1lg thai gian In': khi ta dicu khien d.c Ihao t,IC Ircn Illl 11I¢u thc() Ihi\i gian: IhCii gian Ire qu,in tfnh \"it Ih('ii gi':'lIl Ir(: Ian Iru)-'"cn

174

Thll'i gian tr~ quan 11nh (hwc the hi¢n m[tC djnh lrung ng()n ngCr VHDL GlCt II"~ thi:1i gJan tn~ qU{ll1linh lit dt) dili gitii han dn Ihi(,'1 u'la tin hicu tAc dong d~ thiet c6 Ih~ ph,'tn (rng vc1i sV xufit hi~n Ifn hi¢u d[iu vao Neu thai gian 16n I,.ti cua tin hi¢u dfiu \'ao khong \"lI01 qua gij trj thl:fi gian In! qu;in tlnh thi lTIi lch sc kh6ng phan lJng v()'i s~r Ihay dOl ella tin hi¢u Th()ng s6 thai gian Ir~ qu,in tinh dU'<;1c sU: dl;lllg lrang

quS trinh 1116 hinh hoa cac thiet bi so d~ loal Irir s~r xu[.t hi91l nhOng xung 11hon \'.li dflU \,~IO

Thdi gian tre Ian truycn Ja thai gian In'S xual hien khi tin hi¢u di qlla ll1'.Kh

TiI khoa transpOI't dV<,"ic dung lrong twang hQ"p thai gian 11\': lrong phcp g<ln lu tho-i gian Ir~ Ian truy~n Neu khong slr dl,lng tiI khoa transport trong phcp gall tin hi¢u thai gian tre se dVQ"c coi lil thai gian tre qUiln tinh 1l1()\

each null d\llh Vi~c SLr dl,lllg tre quail I[nh Vll tn~ Ian truycn tao nen nhu·ng hi¢u Ling khi\c nhau len qUi} trlnh !TIO phong Chung ta hay xct qua trlnh sau:

sij.!;nal S: BIT :::::: '0';

prol'l'sS

hegin

S <= ' I' after 5 ns ;

S <= '0' after 10 ns:

end process:

Trong c:tu I¢nh thCc nha! he thong 1110 ph6ng se djnh I\ch lrillh cho ph':p g(ll1 tin hi¢u S gi,.l tri 'J' saL! 5 ns linh tir Ih(1i di~m mo phong hi¢n thai D6i \'(1i cflu I¢nh thCr hai, h¢ 1116 phcmg se djnh Ijeh trlnh eho phcp giil} gli.'l If! '0' eho tin hi~u S sau 10 ns Ifnh tir thai di~1TI m6 ph6ng hien thai NhLf V(ly, du l¢nh thCr hai sc xoa b6 kc·t qua ella phep gan thu nhAt bui VI gi<.1 Irj thai gian tre 1;:1 thoi gian tre qUiin tfnh GIU I¢nh thlr nhat chi ra rtmg thai gim1 tre qu<.!n tinh ella phcp gi.1.n 1;:1 5 ns, trong khi do cflu l¢nh tht! hai khil.ng djnb thai gian tr~ qUol[\ tinh ella ph~p giin !~I 10 ns

I\'eu doi cl10 hai phcp gan trong ctO'.1I1 chu·ong trlnh tfen, ehllng la nh(lI1 dU\1C qUe! tdnh duoi day,

signal S: BIT:= '0':

)11'Ol'l'SS

begin

S <= '0' after [0 ns:

S <= '1' after 5 ns : wait on ClK :

end process:

Trong trueillg hq'p n:t:', du ICnh g<in thu nhat se X,-lc dinh IDQI ph~p gan gia tri '0' eho tin hi~u S sau 10 ns trnh tu thai di6m IDO ph6ng hit;'11 thl1'i con phep giln th(i' hai ;.,e :de d!nh thao t<lC gan gia tr! '1' eho S sal! :) ns so \'l)i tht'J"i (ticll1 hien Ih{ii l\'hu \,~ty khi h6 IDO phong htlt dUll thlfC hi¢n, d.c giao t,.i.e eua phcp g<.in thll hai c1U<,K t1wc hi9n Ihay eho cac giao tik ClW phcp g{1ll thll" nhtit Dictl do c6 nghl<l Iii, chi c6 phcp gan gia tr[ '1' cha tin hi¢u S tal thl1i diem:) ns tfnh tit thai diem mo phong hi¢n th0i se c1uQ'c th~tc hi¢n Nc'u lrong dOi lt1 clllwng lrinh lren chung ta Ihay 1h0i gli.\n tn: qu<ill tfnh bhng thoi gian tre Ian truyell nhu Irang cta'.H1 clllf(1ng trlnh duai day, k61 qu,i thlle hi¢n cua qua Irlnh siS thay dOl,

signal S: nIT:== '0';

process hegin

S <:::: transport' l' after:) ns :

S <:::: tran!olport '0' after IOns;

wait on eLK:

end process;

Trong do • tIl chuang trlnh nay, vi¢c gan gi,i tri '}' cho tIn h!¢u S se dlf(~C lilm tre :'i ns tlnh tv 1h(1i diem m6 phong Con phep gem tin hi¢u t11lt hai se t11f'm m()t thaD tae m{1i cho dieu khien eua tin hi~u S Dicu n:1Y co nghla LI '>C Cl) hai thaD lac cluqc IhLJc hien: mot Ihao 1.le gall gi<.i Irj x,iy ra ,>au :) ns linh til th0i diem md phong vii 1hao t,k gall thu hai se du:(}c !h~tc hi¢n sau 10 os linh tLl" thoi diem 1116 ph('mg, Kct qUt'\ I:t lren du'ong tin hi¢u Sse XU[lt hi~n m()\ XUllg h~ng 'I' co ell) did:) ns t<~i th(1i dic'm:) ns Ilnh Itl" t!1('1i die'm hi¢1\ th('}j

176

Trang VI tiL!- dang xct 6" In.':n Chlll1g la d6i ch() hai phep g,in nhl! sau:

signal S: BIT :== '0':

process hegin

S <== tnlllsport '0' after lOllS:

S <== transport' l' after 5 ns ; wait on eLK;

end process: