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//可直接透過synthesis tool用於PLD，FPGA不可 LUT delay則要採其他方式。, _8 i V5 l% j
//所有註解都要保留
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" f N0 @; H% z2 F`timescale 1 ns / 1 ns
5 q0 h5 a5 ]: h- {9 ?' Bmodule xclk(sclk,ena,set,outp);
X" r! ~; T& A* C8 j3 O; {: o& l( x, ?8 z) Z7 O# b, g
+ j. j3 E: n/ [1 x a
( s- R% @! m9 U: H9 ]input sclk,ena;* w# U' V, N( \1 a g: d" ?
input [1:0]set;: n0 O; i4 a8 v
output outp; - B- @3 ?3 Y6 [" J x
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wire outp;
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8 ?6 A! q% B! f' c3 w( B. |
l8 u P f, A: m- c& P( l& @
|6 @7 s) f( X( v/**** Node preservation for nodeA **************/9 ?, g: N) y: h7 z
8 g# U" p( ^1 E1 _2 ?% X; }+ s
* j* ^$ M/ u Z2 Q% ^
//exemplar attribute nodeA_5 preserve_signal true" k2 @ Y8 X( ]" a5 g# p
. o2 b( f" j2 i0 W7 I
//exemplar attribute nodeA_4 opt keep
- S" ~$ z1 g/ F3 r$ J5 B
; I$ w5 d& o! R/**** The following comment form also works ****/" q. X6 K9 E% ]0 F) `" f
$ P: i% [& R, n6 J; j4 L8 B1 r
//exemplar attribute nodeA_3 preserve_signal true0 T' J; s6 i5 J1 a- {
" }/ m I( F' V" ]. e% }/ o9 K//exemplar attribute nodeA_3 opt keep
' J1 d% h5 b3 B, z+ U' l& C
4 Q( Y0 W; ^( M. F2 ^! t/**** The following comment form also works ****/
& M- C i0 w8 N! j4 W" s. ?' I! l& E) F, x7 u! x! }. q1 {/ h$ f: J
//exemplar attribute nodeA_2 preserve_signal true
* h4 S' _9 N* c( `! n8 i: S V2 z# X& _' \4 P/ F. N4 J
//exemplar attribute nodeA_2 opt keep! Y8 A& c# l- B8 p9 `% y* ^
1 x( J2 ^& |9 ?2 M/ s% U* W
/**** The following comment form also works ****/
+ c. u/ V4 S3 _6 `
* E5 v+ X, M& }//exemplar attribute nodeA_1 preserve_signal true
}$ l$ J/ F& } A: I0 n1 Q
- ?+ K) j. \# m//exemplar attribute nodeA_1 opt keep7 z4 e6 O+ j# g% x' W) a
/ O! s- U% j J6 H( j
* t% G2 B& X# b7 a1 G; \' \! }/**** The following comment form also works ****/8 `1 E5 ] g( w: F
2 F$ x, E. e* j) N- ]" t6 m
/*exemplar attribute nodeA_0 preserve_signal true4 S5 X( y- U# W' o7 p, _- }
' S! O: }4 u: Z4 F
exemplar attribute nodeA_0 opt keep*/ _4 W$ x U) K& G: @
2 b& }3 G/ h G$ O5 s
5 X$ w" C, g, G% Q5 s6 ]8 \ + A, y5 | v z5 e7 k+ ]
! A5 q$ Q6 v8 ]4 ^( k& |9 W+ b4 q: P9 m6 p3 X1 O+ g
2 N- ~* V3 e U$ Z$ `9 d
/ r, k7 I- H# L
( w+ ^! `& P( C% ]
# d, m1 C ~, X8 b* _+ a9 J$ h0 i# e4 y$ X
wire nodeA/* synthesis syn_keep=1 opt="keep"*/;
2 W; d0 I6 g( C) m3 b Y8 X6 awire nodeA_0/* synthesis syn_keep=1 opt="keep"*/;
& s5 i9 `1 R/ }" B7 Ewire nodeA_1/* synthesis syn_keep=1 opt="keep"*/;
4 ]5 v# H5 A+ J0 [9 Bwire nodeA_2/* synthesis syn_keep=1 opt="keep"*/;
% Q! q z- z, kwire nodeA_3/* synthesis syn_keep=1 opt="keep"*/;4 j+ K) k7 F6 e P6 [" Z5 F
wire nodeA_4/* synthesis syn_keep=1 opt="keep"*/;
: K( U4 ]0 L3 _" _
! u: @1 s6 C+ `* t8 G0 ~( Lassign#1 nodeA_0 = sclk & ena;5 z" G2 k/ ~' e$ {' P! a$ l9 b% x
& A. v2 ]& L3 g6 Massign#1 nodeA_1 = ~ nodeA_0;: `9 l+ a! B7 u3 E7 d2 c7 o
assign#1 nodeA_2 = ~ nodeA_1;' H; L; c9 B, E
assign#1 nodeA_3 = ~ nodeA_2;
8 |# t( }- M( B- J, U& Bassign#1 nodeA_4 = ~ nodeA_3;" x1 i) q2 V5 M& h- s
" {( Y8 w9 A& }9 G. e2 X
reg xout;
S: \, |$ T/ K* |: z( {. o. }' l* ~' k) f4 ~0 z9 P+ P
always@(nodeA_1,nodeA_2,nodeA_3,nodeA_4,set)" D! W' m& N" s) V! q+ d
casez(set)
8 o3 P$ F6 Y* p# f# g" K3 d) r) b 1: xout =#1 nodeA_2;
) U: ?8 [8 l- J( | 2: xout =#1 nodeA_3;: R; ^" e. o+ [& _' q* Z# o J, H
3: xout =#1 nodeA_4;% \6 N8 V- g b% w' |/ {! l
default: xout =#1 nodeA_1;
/ I; E0 m, D$ K8 d- ]' D endcase5 d' D( ~) U: x9 j
: H4 ~% s0 }9 Y7 u4 c' n# Jassign#1 nodeA = xout;
x1 B, m: x8 Z* g( @. \! Z0 Hassign#1 outp = ena ? nodeA^sclk : 1'bz;
7 Z8 {) i0 s; ]. X, G3 c7 ^) B" @0 c
. R" D _8 V, Jendmodule1 o6 |9 y$ h! h
% s& K n& C- S* b$ c
8 m4 J$ h5 G$ J- B; p* p0 i0 V
3 ?6 ?: [* A) J P`timescale 1 ns / 1 ns' R3 ?/ H8 q6 |0 {. D" F
module xclk_tf();: G: O7 d8 b7 c& d. G# ~9 U2 w1 c
+ i, M3 H! b. D6 D, R
// Inputs
" l8 q6 w2 Z& I reg sclk;" g$ n! Z2 q n* e( Z7 N; I! M; O* y
reg ena;
& w) m( H- \- _8 v( M6 B6 e' d reg [1:0] set;
& Q4 e' R, k8 r9 [7 P6 i0 z0 H7 n; d; m2 V7 ^
6 r5 Z7 h- @/ C& U9 P/ u. @0 c
// Outputs, d' l. y5 \) x- B( j
wire outp;
% {: W$ j! j ]" A! m# r* ]8 e4 r {. M9 q+ Z! |5 E4 P
' E' O& K! y0 i. s. y. M
( i" G0 S8 ]. N D
xclk UUT (% w2 K6 q+ x+ V0 v0 {9 j0 u/ j
.sclk(sclk),
% Y, V& b! B+ E. u .ena(ena), 9 V: j% h& s: R: {; A
.set(set), & s* V8 ^) S) ~7 A/ N4 l! k' J
.outp(outp)$ v( S% z& E) S% A6 _
);
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^3 u) o3 {: D3 Z' G
- A) y4 [/ a3 D. E5 m7 r6 v initial begin/ x1 g0 k' S' M1 h" D9 E a0 V
sclk = 0;
. P- h5 x, M1 m" G7 } ena = 0;' i* d" k+ s( m3 }
set = 0;7 G! Y. |/ M& |
end
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l6 m1 l! {' ^- Q' Z" C/ Y$ Z8 a1 n3 Z' }0 \! l
always# 5 sclk = !sclk;
! c( j6 Q _" q$ V$ Q+ J' ~# H
/ q# c- g5 |! |* W9 g+ c3 j& cinitial begin
/ O1 W* |9 e8 q/ ] #100
3 `9 F- v/ P9 J ena = 1;, b: T- H" I' J1 {8 l. j
#2000 6 v% u/ @" u) _: B
set = 2;2 J' o; B4 O8 b4 C8 _7 C
#2000
3 S1 q2 F" X' w- t- A% ~+ j set = 3;
" _( }, _* }6 I; o #2000
% M8 z: Z2 e% s+ S& g" R( Q8 ^ $finish;
/ m* K; J: T9 Rend
' ]. t3 p& T% N4 j' Nendmodule // xclk_tf |
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發表於 2007-3-17 11:29:24
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