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下面分別是我寫的除頻器及它的激勵源) C( @& C) m6 t& J3 Y: ^
但我使用modelsim時卻無法正確的讓它產生振盪
* }" U% A e% V: Y- [) |; I' c該波形完全處於0狀態
G# k& B8 u; Y2 w/ D但實際用fpga燒入以視波器測卻可測得其波形
0 J' q3 I. q8 \, v( u+ g不知道是modelsim本身看不懂我寫的3 e' R3 w; H, N% l" h2 B: j& k- J
還是我根本就寫錯了) O$ f& I+ {- S+ i
又或者是testbench沒寫好? B9 G$ x( w0 ^: Z; \& x; w& b
煩請各位大老多多賜教!!
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module F40M20M20k50(F40M, Rst, F20k);. `$ ]8 b2 [+ G; [1 W9 t' \& @7 ^: t
input F40M;
g2 l4 g$ D7 j( x input Rst;$ n, {4 E+ Z. _" N/ [3 l1 B
output F20k;! E* p5 k- K( y5 ~
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( \$ k- j" X9 l5 `5 h reg F20k;9 U/ q- g) e( E6 p' G
reg [10:0]B2000;. z2 s: P- J2 i% L2 W1 j
reg Count;# x! V% _. m+ u/ m0 r- C* f0 m2 j
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8 L* j" s9 L* Y/ {) p& p- ]' P% Ealways@(posedge F40M)# c1 h; j7 _; z9 y: b2 O
begin
/ x$ Z8 f& y- G jif (Rst)
3 |4 x/ ?) v' ^4 J* T8 U begin
6 K& Y( v1 u4 w z) o B2000 = 0;
9 u5 t1 ]( S" v2 _3 N/ _: Z8 g% E$ P Count = 1; 9 t G4 {. v4 R# }4 |. P
end+ z& o9 ^6 Z" \ v
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else
5 N, S. i5 C# a6 h begin
/ ?3 K/ _* T0 O7 i2 m7 [ if (B2000 == 2000) 6 S5 O8 H# s' [5 D) r
begin+ G6 ^! N4 d9 y4 ]; }
F20k = ~F20k; 5 t& D/ N- M, _) c
B2000 = 0; 3 }# \" B2 z3 w3 z$ M) _$ ~
end
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begin
0 i. y1 Z9 T) x8 J3 q H B2000 = B2000 + 1;
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end
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end K$ ? D4 s5 s6 x- e7 N
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endmodule
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) o& y7 l2 @3 }, F---------------------------------------------------------------------------
6 Q; s3 c, E+ [! T`timescale 1ns/1ns
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$ Q H/ ~2 ?! |1 F3 Vmodule testbench;
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reg F40M;- F, p2 X9 M/ ?; x3 _0 h7 M
reg Rst;
. o0 p& {/ l) G, B1 N# [# a9 ?3 ~wire F20k;! g9 s1 c( ]+ |# l$ N* N$ [5 {
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F40M20M20k50 ReiRong (.F40M(F40M), .Rst(Rst), .F20k(F20k) );
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initial $monitor($time, "F40M = %b, Rst = %b", F40M, Rst );
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- J$ {9 X0 w2 y) Zinitial begin5 O) ~8 _3 e# \6 ^" F6 X
: V, X1 c. I6 R- ~& n3 v1 U; m F40M = 0;
8 A/ j- c2 I C z# L. z) W Rst = 1;
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end- @: Z$ x7 Z- o: Z; M% L6 O
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always #25 F40M = ~F40M;
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begin
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Rst = 0; 9 K9 M9 i* F/ M
end
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o$ p9 |9 N9 pendmodule |
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