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小弟寫了一個mux 4 to 1的verilog code用xilinx + modelsim SE 6.1f
/ L2 |9 I. w' |+ \. g0 p5 m O" S跑模擬- s/ O$ ^. ?; b% V* z k/ m
可是跑出了的波形都是high Z跟unknown
6 z( h& Z5 O1 F. ` f% H也就是訊號資料檔沒灌進去
% j+ H3 ?; s: q- t想請問各位大大( v/ Y; G, x! g8 q' V
我該怎麼修改這個錯誤: u" s5 {4 }' O; `
$ I- n; X7 s: {1 {! K=======================以下是verilog module code======================# }1 P6 Q9 R% p6 m2 N# c
module mux4_to_1(out, i0, i1, i2, i3, s1, s0);7 l& ]5 z a" F& r. C/ K# L+ M" c$ }& S
output out;
2 S7 |. u0 r! e# u6 t( u' o input i0, i1, i2, i3;1 O" J7 c) D7 K k( e
input s1, s0;3 a# r3 K0 K5 ^& N n
//out declared as register
9 [# R5 t$ _- c ^ reg out;
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7 H' m" ^# [* U# l. ~+ [% F: ? //recompute the signal out if any input signal changes.
: }; R$ g( i F# {! u //All input signals theat cause a recomputation of out to occur must go into the always@(...) E+ `& U5 g, P7 V; P3 Z5 C( p2 Q$ j
always@(s1 or s0 or i0 or i1 or i2 or i3)
, c2 Q- f- a% S$ z0 F! J begin
: Y3 @% A9 Q5 }. o8 A- g! x4 A case({s1, s0})
, N. N) K! M$ g" P, y 2'b00: out=i0;( c+ P/ ?% h6 k5 g
2'b01: out=i1;
+ m3 _+ y# G' r3 z8 w" J% r- e 2'b10: out=i2;0 b" _, x* X! G2 {
2'b11: out=i3;( F1 y0 u, f" H2 @
default: out=1'bx;
% [& l" ^! Q3 ~ endcase; b! ^% h( ?4 n' z ^! w% j9 c) ~
end% B9 V8 S( ]1 }! \1 j3 E1 f
2 K7 _3 B- x$ M. h: ^endmodule6 w! q8 ~" U' ]3 O. E) e
=======================以下是test bench==========================6 T* ~3 V6 U# h+ ?. j; E+ j2 t5 S
module stimulus;
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, T, `8 ^7 k* V& {" `3 @ // Inputs
2 ` p8 F- t/ w reg I0,I1,I2,I3;
8 _+ h1 q+ q5 _3 }8 N6 u& I5 T# b reg S1,S0;
& W. G. B. W; G5 P" |% O6 V // Outputs0 ^1 c, h4 |+ R% n
wire OUT;
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// Instantiate the Unit Under Test (UUT)
( _7 T/ n3 h. c! `& I mux4_to_1 uut (' l/ s, q" m1 n* M- \) H
.out(OUT),
* t8 e* g( u6 O .i0(I0),
) u* @ l( e& L8 G& t, U i/ g! w .i1(I1), 6 I ~8 e, a, h3 E
.i2(I2), $ h* o, \4 X& L- T, e! Z
.i3(I3),
: A" m2 z8 t! N8 M& A .s1(S1), + K: {6 c9 V& M- l" y9 @: h* p
.s0(S0)- X7 y$ D9 g6 T" j9 |5 ?
);4 X& D$ n( C [9 `: A6 r4 g
( ^5 M2 d1 d5 h! I% @7 \: M initial begin6 q4 f% b' R9 E9 s( R; V8 u6 k9 x# X
// Initialize Inputs! x( q, |3 }; K! X2 i
I0 = 1;, b+ {9 X6 R2 g4 \3 H, c
I1 = 0;
- x+ }2 p8 \3 G$ a I2 = 1;
9 \3 h, ?( i" F% @3 Y7 l I3 = 0;
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( l2 T! w$ z p2 q: y. b #100 $display("I0=%b, I1=%b, I2=%b, I3=%b\n", I0, I1, I2, I3);, V' z7 E, E w9 s J( X& o- u. W6 M
//Choose IN0 N7 f5 N+ P- s- a/ f$ o
S1 = 0;S0 = 0;
! j& l0 {$ M: g! R y, I$ O/ H #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
% G" A2 f, O: D; w' B3 p //Choose I1; o7 P! o. `' y. D
S1 = 0;S0 = 1;$ B& j2 h! {) r
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);4 G! u' l! b3 N3 L6 R
//Choose I28 F3 }" }( C- X
S1 = 1;S0 = 0;* C/ Y% o) _$ _
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
0 q# t1 Z5 ]0 x* V3 b //Choose I3
# y* K+ ?9 J0 d" w/ X- `6 f S1 = 1;S0 = 1;, V4 H, y% }- U) q9 o- W
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
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O: n! Y5 Z6 Z3 Z
" [+ J* f' l% G- U0 @2 e end( V; ~" ]# _9 {
) x) ?: o9 ]$ X+ k: k
endmodule |
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