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小弟寫了一個mux 4 to 1的verilog code用xilinx + modelsim SE 6.1f
2 x' b, j; }4 j. {" {$ m, [# K1 L跑模擬
: c- X6 T+ T0 P1 |5 K可是跑出了的波形都是high Z跟unknown
& r a( }3 D# \# i, F也就是訊號資料檔沒灌進去
- Y3 `* m7 j% T2 K" i: H. ?/ r想請問各位大大
3 N' n! m! W J; Q- Q我該怎麼修改這個錯誤
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=======================以下是verilog module code======================9 j* u9 s/ I/ _
module mux4_to_1(out, i0, i1, i2, i3, s1, s0);' J6 |4 Z. U0 Z/ }9 x
output out;
/ p q1 K: ]/ K( H8 J! U: u input i0, i1, i2, i3;
: L' S" {2 d. E1 a; t4 y4 P input s1, s0;6 ]! i/ B9 `+ f. b
//out declared as register' d7 F% K# y. ^8 V+ k5 ]
reg out;
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//recompute the signal out if any input signal changes.
8 ]3 m% ]6 h( [. h! m' J$ S1 X //All input signals theat cause a recomputation of out to occur must go into the always@(...)9 S. w( ~1 j2 z+ x- F( k- O
always@(s1 or s0 or i0 or i1 or i2 or i3)4 b G! A0 n1 P0 F3 c J
begin1 Z" N+ [- T% N$ N1 g2 ?8 e. ~
case({s1, s0})
7 t d7 H: Z9 {) S. |0 i- e6 @ 2'b00: out=i0;
" f3 u# U8 n% I. q- B* w 2'b01: out=i1;( H! d0 C/ b+ ~# f) F7 N$ L
2'b10: out=i2;
" q5 h- w4 f; h% G ^5 y 2'b11: out=i3;
7 K# w. o8 S" \/ g Q default: out=1'bx;4 @( o9 z( l4 `1 v
endcase
5 c6 b) u* r; F; \ end+ f* H: @4 P& }8 m! S
4 z# W( U c" B# O5 Q" [ Jendmodule
' M4 R |7 e: X; D+ A' w=======================以下是test bench==========================& S) F1 [4 G# i y: ~+ T
module stimulus;! ?& k. f7 V& ^4 V' Y
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// Inputs& ?; O; R! S' H0 m
reg I0,I1,I2,I3;) E8 T. j# |6 M" T6 v
reg S1,S0;
4 P, `1 \/ G) u, c0 w // Outputs* h8 s# p' H# o7 Y$ d0 q6 Y
wire OUT;
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// Instantiate the Unit Under Test (UUT)8 ?8 J. O% F% g7 r; I
mux4_to_1 uut (1 X- V; m9 Z% i+ _1 g% S
.out(OUT), % {/ B3 U- e: I8 x: P' P
.i0(I0), 2 @2 B7 u5 H1 A! H* X
.i1(I1),
5 c3 |$ g0 B' @! X; D1 I3 o6 f .i2(I2),
( }/ w7 l) ]5 b: R* I- N. C& x .i3(I3), ! |1 z! O& l$ |2 b& @5 V
.s1(S1), : X6 Z& a& D2 `$ w" u
.s0(S0)6 K0 S! ^' t: F; ]* Y
);
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initial begin
, o, {; ]9 l7 C, X$ F // Initialize Inputs1 d8 t0 s0 L' o9 O% M
I0 = 1;
; U( _7 q5 K3 @1 s5 [ I1 = 0;
) G! V3 O9 w7 @8 u& Q# f* D I2 = 1;& J: m+ p* \( S' _+ _9 e1 B
I3 = 0;# P" _# J% Q7 B. R
! W1 r/ J! }; @7 c' G- y$ V u #100 $display("I0=%b, I1=%b, I2=%b, I3=%b\n", I0, I1, I2, I3);
# M3 t6 o2 S$ r3 [6 q. r //Choose IN0
% t3 x3 V2 D& @1 v) c. L S1 = 0;S0 = 0;
2 C. Z" T. [" ~0 j! v5 p #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
; W" F0 I. w$ L: G7 S' ]2 D0 U //Choose I1
# M% ?: `6 V' ?! e9 ^/ g S1 = 0;S0 = 1;
& Q; ~/ v4 _, a6 O, _ m #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
2 I0 Y6 \, p7 E: n* ~( G //Choose I2
, {. H0 H- t; T; Z9 n) h" Q- O S1 = 1;S0 = 0;6 l. | P# Z8 E" @
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);) R* R7 ^" w! Y: G) R+ |" E
//Choose I35 r; _2 m$ d5 x
S1 = 1;S0 = 1;
! y6 Y/ e8 v3 Q% F+ F3 F5 \ #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
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endmodule |
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