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小弟寫了一個mux 4 to 1的verilog code用xilinx + modelsim SE 6.1f7 t: e, L Y& f
跑模擬6 V2 a9 {* w( H5 `6 C; Q' K2 x" _
可是跑出了的波形都是high Z跟unknown 5 A# Y% L& W4 P
也就是訊號資料檔沒灌進去: S& M. t$ U1 j1 N
想請問各位大大1 E6 p2 {; {5 x$ {1 z
我該怎麼修改這個錯誤
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7 f# g3 e* T5 O6 A; u=======================以下是verilog module code======================
; n4 T) q+ M! \$ M1 ?0 Jmodule mux4_to_1(out, i0, i1, i2, i3, s1, s0);
0 j: x$ V5 [$ Z7 p, B4 e output out;, k4 i* l1 T6 I( M7 z
input i0, i1, i2, i3;
0 y0 [6 w% t: e# N; U input s1, s0;
7 h3 n p' o3 z. v- y //out declared as register
) u+ D, G/ A% f. {# O- b- e reg out;1 D% ~4 s: Z6 a; h& ?
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//recompute the signal out if any input signal changes. C# F8 T4 A2 u7 W1 U X
//All input signals theat cause a recomputation of out to occur must go into the always@(...)
& I( v' N5 h* b4 W& I( N always@(s1 or s0 or i0 or i1 or i2 or i3)5 g" _' Q+ A7 r1 ]& Y- z. [/ Y
begin
& `2 B' V; C4 w case({s1, s0})7 e7 ^/ w/ F8 d: u
2'b00: out=i0;" E" ~0 }1 s$ |, v* O4 C
2'b01: out=i1;/ o7 \# ]+ r& T5 A! e
2'b10: out=i2;' h# |6 f7 m5 W9 |) w% S+ I% C0 S
2'b11: out=i3;! u1 ~+ E: b1 @' z( ?: L, @
default: out=1'bx;2 }* T5 n& @' v) _+ T. P9 j6 `8 B2 b
endcase
) X, z4 y* z3 d end; H" |3 g) x; A8 C/ g
' I) z7 X9 |- {! s& k1 y2 T; e Hendmodule
3 t- P% R. y! P* l9 o+ B, n, v=======================以下是test bench==========================
2 u+ t: a% F+ _" e/ F3 |module stimulus;
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// Inputs9 D; B" i. D" g% d3 Z
reg I0,I1,I2,I3;
0 y* y: h; ~1 l: K* z8 d0 Y G reg S1,S0;
c6 |$ m0 W% u9 Z5 e // Outputs* g3 v1 ^/ a+ B% O4 p; e0 y; t7 o
wire OUT;- f7 u1 [' t& d% K9 ^
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// Instantiate the Unit Under Test (UUT)" w! T* P: U' J* U/ D2 b* n
mux4_to_1 uut (' W0 `5 x: X3 |& c. F$ U, i
.out(OUT),
1 q& P4 _; Z7 i7 D" c- }9 Q8 D .i0(I0),
* q9 Y6 K3 m# J6 R# B: C .i1(I1),
+ O" {( ?7 i2 F- l .i2(I2),
) s4 I9 X9 L: g' u0 f2 c6 W .i3(I3), 9 R+ E* d/ C3 ^# G% ?
.s1(S1), + O( @, [- `! {% F0 i3 |
.s0(S0)
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initial begin5 l9 B9 m! o9 S( |
// Initialize Inputs
7 ^+ t6 i, V5 i( E' W8 Y, D1 z I0 = 1;/ r, n5 J t/ V/ a9 v/ m
I1 = 0;; D* [0 A) D( t
I2 = 1;) Y$ |7 I# N& D0 g" Q* t1 [
I3 = 0;
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#100 $display("I0=%b, I1=%b, I2=%b, I3=%b\n", I0, I1, I2, I3);
4 H9 @# R7 @( o s$ \ //Choose IN0
4 r4 n% @3 z( U7 I S1 = 0;S0 = 0;! E2 w7 n+ x* v: t) A
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
9 b# t, l! O8 x //Choose I1
$ E* Q3 M3 R8 T: D4 S$ C2 h) x S1 = 0;S0 = 1;
( S1 ` I7 |$ X* Z #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
9 g$ ]/ a( Y/ m //Choose I2
; j6 W" j+ B, }8 n/ R S1 = 1;S0 = 0;
- M5 h9 N9 X4 C0 E& L4 e0 B9 j #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
6 Z4 P2 s4 E7 |; W" s9 Z //Choose I3
: i9 {$ T& U0 o& v S1 = 1;S0 = 1;
7 k6 l/ I, A; Y9 W9 z5 E #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);$ ~) M% Q$ @" K
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end' W7 v0 A- g) c
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endmodule |
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