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下面分別是我寫的除頻器及它的激勵源4 i# K/ d7 ^, q! o% b
但我使用modelsim時卻無法正確的讓它產生振盪' ^( B1 {# W5 V. f3 [0 Q
該波形完全處於0狀態
! Y$ J) s% J2 s1 U5 v但實際用fpga燒入以視波器測卻可測得其波形
+ c5 V& ?4 Y5 T) W2 t& ?不知道是modelsim本身看不懂我寫的
9 |+ Z0 v; M! W4 z6 c6 L6 i1 j還是我根本就寫錯了4 `: [& G/ ^9 j* m j
又或者是testbench沒寫好?
8 b: h! a1 E. `煩請各位大老多多賜教!!. y: M+ _+ M2 O$ y2 n6 a. ^
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/ M0 A( J! U" S3 N$ q2 h% Bmodule F40M20M20k50(F40M, Rst, F20k);
2 U* J' g5 M, i; m* Z8 L+ W- I input F40M;1 v9 Y7 l4 m$ d5 y6 f( Z& O$ {
input Rst;) q' Q. k& U5 {: |6 u. R
output F20k;
+ C; P4 i# P* i' E5 V , G5 l0 c; w+ H# i- N3 t7 G& m) Z
! F, r9 D/ Q5 c7 o) Z% t, m0 c; v+ F reg F20k;
" w8 X Z* Z1 V& V7 x, I reg [10:0]B2000;
, f+ ~' k0 g6 i reg Count;
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$ W- w# o" v* q& |" D& r2 ]- r
always@(posedge F40M)
( f. x) M% j' I$ cbegin" Y/ U, k, J+ c4 g( \8 f
if (Rst) O, o+ z6 S+ W: w; l( |
begin; V9 c; Q. S; }- Y' p6 A
B2000 = 0;
4 E; u. f' T3 | z1 |$ j# W6 z! p Count = 1; 3 A+ w9 _5 d: c9 G6 d9 x
end
0 d7 [- l1 o0 k1 r& x) d 5 H- k" w! ?6 Q' R$ \9 A
else
+ ]0 @* |* G L: H begin
' S3 _4 j3 h1 a if (B2000 == 2000) 5 w* M) p( D ] Z2 G. g4 n+ F% f
begin, K v' R0 ?7 p, N+ T! g* {
F20k = ~F20k;
1 r' |2 I I& B0 Z B2000 = 0;
7 `' C% Q6 T/ ~) }, O7 O% d end
! M4 V7 ?9 c$ ^8 x; W else
6 z# V: i$ G' z! @0 s6 }: Y0 A begin
; x1 f. ]- e' _" F9 Q B2000 = B2000 + 1;
2 X. V( K' ]$ M( d1 |/ i1 U end
2 @# I1 K: r9 _4 b end
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end& d% Y% i/ a4 W# M
* C, `* P$ ?$ b# K) I7 j0 x8 f% Iendmodule
6 c; K- b" N9 @$ P; ~5 U3 ]" U+ Z/ E% ~5 F
---------------------------------------------------------------------------
e& m3 ]3 {# G+ q% {) ]`timescale 1ns/1ns
3 k' n+ c! I1 m' |3 z9 `1 ^
& D$ ?0 ?3 A c0 ~module testbench;
" J2 A& x6 X- y
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, o# j! S; f9 z! h* u( {
reg F40M;
7 |/ P! b3 `0 @3 p9 sreg Rst;
# G& z* v; A6 V- G: p$ E! ?wire F20k;% M2 K: V3 h. N9 q1 W
% p. F* h% _0 O3 e3 o8 Z+ p; \8 Y" T M
F40M20M20k50 ReiRong (.F40M(F40M), .Rst(Rst), .F20k(F20k) );
q( T6 \' n4 e" P [6 ]" z' X1 K0 \. ?' H5 X( P( f7 M
initial $monitor($time, "F40M = %b, Rst = %b", F40M, Rst );
% p3 o9 s4 ]" Q k1 m! H/ d- S4 J, i
initial begin, p7 Q( D4 s4 Z6 P
% I W8 u" H5 l2 N6 N' O
F40M = 0;5 I6 u6 Y5 ~* z: G, a7 E
Rst = 1;
4 N5 x! H) h# C1 w% z* Q. D* U9 Y
. u% }2 l) q/ q1 S3 X. Q! Gend( m2 l6 `: `' M# D# [, |0 @/ H) S
7 d& [1 W$ y" o0 o always #25 F40M = ~F40M;$ b! C: e% }; j( o3 X
initial0 B) P$ ^" m9 ~6 C$ M+ r) g. `
begin , b% @8 f% O0 _/ _' ~, q8 s
#100- d% z n! P/ n, [5 e; H
Rst = 0;
$ z$ g4 v6 ^) u l; j7 G end
$ I) C0 [2 u& A: `" e+ a+ r% D( t9 Q
endmodule |
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