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下面分別是我寫的除頻器及它的激勵源$ V3 A8 _2 |( y9 t( _8 t/ ^0 C9 F- f' B
但我使用modelsim時卻無法正確的讓它產生振盪
6 Y6 h9 {" q x" Y! A2 y! e該波形完全處於0狀態$ P) I) p q8 k! |1 v
但實際用fpga燒入以視波器測卻可測得其波形
0 i7 x! P, E( F6 ]不知道是modelsim本身看不懂我寫的3 X2 v% j7 H5 a
還是我根本就寫錯了
0 ]$ F0 c- x' X2 @' B6 Q f# n又或者是testbench沒寫好?# {) q1 A: f" c& O* d
煩請各位大老多多賜教!!9 N/ A3 @: s; L) i+ p5 F5 p
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module F40M20M20k50(F40M, Rst, F20k);
1 P t/ A6 \2 F1 e input F40M;
, Q4 _, G: R8 W, g! e7 O' n input Rst;5 B8 V- O) b$ a
output F20k;
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reg F20k;
; r4 H+ D1 u( _ reg [10:0]B2000;5 P/ {% E7 f0 Y6 s4 b4 [
reg Count;: K( v4 C7 Y+ _6 b. A( d! _/ c" h
+ _6 ^7 j t9 V# C, a/ T$ K1 P. D$ _' u" l
always@(posedge F40M)7 g E. H7 N9 ^2 n
begin
9 w* q. `& z9 h# v3 r3 Uif (Rst)
" e4 i( u8 Y/ Y' s- B4 B7 x begin- M6 Q/ X w" d. k
B2000 = 0;
* x; a2 U; o4 c2 o, b+ J4 r/ O Count = 1; " M5 G2 \) X, p7 c
end
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else 4 ?1 L4 S! U0 Z
begin
2 G+ n$ Y, k8 i+ K: \5 D8 r if (B2000 == 2000)
8 }1 G* s" d9 s1 n begin
! T- O9 F4 u) b$ k0 u5 v6 O F20k = ~F20k; , ]6 ]0 y; t* y: ~. b
B2000 = 0; u+ o0 i1 x( E) x
end
1 P: I& ? p7 o0 l0 X else( ?4 B- I, f3 {, N: z- C
begin. h8 k+ a1 R& ?) `
B2000 = B2000 + 1;
' u, N v2 F+ `% k( ? end2 }6 A5 k3 v8 l! s/ `3 V
end$ l: Z4 l2 ~2 Z* \: ?
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end: [+ s# B/ a3 z: t; L9 d: G7 M9 N
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endmodule7 f+ `; Q: H0 U; g6 [* x
) R: y8 j: g# o/ l' Z
---------------------------------------------------------------------------
+ u. B* B: t+ U# e1 J`timescale 1ns/1ns
9 F: d% y. t' u. w* [/ n0 o$ @5 T* w( _+ r
module testbench;
+ m6 Q+ ` ~4 M; V' k
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3 p/ M6 m' u0 Z) ~! k
reg F40M;: X5 }* p J* i6 x; L
reg Rst;
) |) Q9 i" M' X0 S a! [wire F20k;
* b0 s2 t& U' \
5 |% x$ c% X @! s F40M20M20k50 ReiRong (.F40M(F40M), .Rst(Rst), .F20k(F20k) );
& N a! j/ e& Q. \1 T: z2 a
+ F9 Z- W; K H4 O9 Qinitial $monitor($time, "F40M = %b, Rst = %b", F40M, Rst );2 R' j) i) H4 M3 r' I( r/ f0 q$ Y
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initial begin
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6 H* O: K; z5 E k F40M = 0;
1 y6 d, e5 F: O5 }3 ?* _ Rst = 1;8 O8 |$ _8 r+ C3 V' [5 v }
% |0 F* m( ?; O& f
end( W4 Y2 @4 m0 ?& Q/ r
* d+ {) O1 {) Z( {4 c2 o) r% X always #25 F40M = ~F40M;
6 V5 I7 u5 e: i1 j, F3 n- | initial( _. B7 a- H" t! {( _* E) V
begin 8 L$ `2 e3 s1 c# ] ?; m& m% ]
#100
- M F# M% W) }) U Rst = 0;
* D; d! N8 h; k4 Z4 h7 S' ~/ ^ end
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2 `2 ^3 i3 e7 ^, ~; H% Xendmodule |
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