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下面分別是我寫的除頻器及它的激勵源
/ t9 A1 c# Q$ {; n6 A' R+ Q但我使用modelsim時卻無法正確的讓它產生振盪
- c( e; g, `$ f6 c該波形完全處於0狀態; ?3 R6 H" {9 H5 C4 u4 B* {
但實際用fpga燒入以視波器測卻可測得其波形
+ f! i4 z5 n- W* }不知道是modelsim本身看不懂我寫的! {; [" e. l7 O8 @! i' i
還是我根本就寫錯了
6 i6 S' M* |, g0 B$ \" |又或者是testbench沒寫好?) U& w7 d- ?1 l1 a3 T
煩請各位大老多多賜教!!" h! ?& I9 k. C- Z
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module F40M20M20k50(F40M, Rst, F20k);
, o6 P* Q/ I& q4 h# | input F40M;
7 w( T/ M* v# f+ }7 ^7 K input Rst;
" F% @- X* R2 V5 ~+ e% P$ ]# P1 M output F20k;
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reg F20k;
0 f; ?) f {& i0 z( P4 n. N reg [10:0]B2000;
3 w& j& D! b+ p& |/ g( Z reg Count;
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" i* h, L: T, f5 Ralways@(posedge F40M)/ a0 t! r+ d. v% J. v G9 t o
begin, y h. F) L7 B3 E3 K0 ?* m. R, ?
if (Rst) , o+ x. ^; }! Z0 A, d3 X. ~" {7 _
begin
2 I0 L4 t/ |0 _8 s8 ^- Q2 c- x$ S B2000 = 0; * P* F, D0 S% c/ T* Y/ H
Count = 1; & o, |1 W& \% @ W
end) F7 q% Q. h+ z) ]; Z( _
; c% o8 X1 k x! E xelse
| T5 T- S' B begin0 u, U4 Z" R) v7 Q
if (B2000 == 2000)
: U, B( `: K6 i: x begin
8 _: ~& q" V# b# h2 q ` U6 D F20k = ~F20k; 3 A! U- A C N7 C) z2 f" e
B2000 = 0;
+ x+ h3 X# P# `# Y' O- f end) }3 j9 e" b7 _$ }" e9 p) ]* B
else
5 B2 S+ ?9 D- _- x' U, ~ begin
9 w1 s; W- h; Q) e! b, y B2000 = B2000 + 1;
* L) c1 e5 h) ~ i, \1 F% y end9 {) Z/ s3 \8 h/ D' T7 v
end2 S+ J2 m* `- a/ q
/ A2 b/ L" f- s) ?% u, A0 y4 Q end5 {+ h: }, ]8 G
3 A- g$ h5 x. B: Sendmodule
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---------------------------------------------------------------------------# \' A( w9 w# U' j7 A
`timescale 1ns/1ns
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module testbench;
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G# ^5 b* t; z# h S, `reg F40M;+ E* H8 C; C! ^+ ?& i. v) k: j1 u
reg Rst;. a( M3 m W9 }
wire F20k;& L7 U$ [+ }. P% V. C
& E7 C7 ~3 P0 n F40M20M20k50 ReiRong (.F40M(F40M), .Rst(Rst), .F20k(F20k) );
( M- A# o1 F5 ~, j ]
' I v' W2 m0 e+ x1 L: Minitial $monitor($time, "F40M = %b, Rst = %b", F40M, Rst );
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initial begin
2 b6 l5 d; i5 a% y5 _ / Q8 {& l( p/ p6 f" @2 i7 u. h- W
F40M = 0;
0 Q% o# }8 c* i+ O3 L% O, Z" _ Rst = 1;! x5 t! }" K( O2 ~9 b3 b
7 I3 f$ _0 Y4 i% E; [# u& Xend
) ?. R( x& p) H& a. E
3 G0 Q4 d8 D. t: Z) O always #25 F40M = ~F40M;
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begin
2 o# c |" A7 r6 K; t1 c0 t( x- R: l #100
. D, [. `% M- c$ u Rst = 0; 1 h* V9 ^9 g0 \4 W0 r/ i
end3 d" }9 Q$ g P# Y2 O( c
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endmodule |
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