|
小弟寫了一個mux 4 to 1的verilog code用xilinx + modelsim SE 6.1f
9 X" X, }, a8 Q* P跑模擬/ C8 D" G+ P" ~; r: C8 o
可是跑出了的波形都是high Z跟unknown ) z" P( s+ A# V5 t1 e' ?
也就是訊號資料檔沒灌進去
1 P+ w0 S n' k( E0 N* W想請問各位大大9 b8 Y; K# e' n# a9 W& ]) E
我該怎麼修改這個錯誤
3 H# L4 Y; g* S8 z1 o
! q9 b6 u9 @9 E, m=======================以下是verilog module code======================
+ F7 J; ~+ y- @module mux4_to_1(out, i0, i1, i2, i3, s1, s0);
6 A Y# d7 B# h0 N output out;
p3 s, p: _) B& n' I5 r0 u input i0, i1, i2, i3;
4 E" T1 C# r9 R; |& K; d input s1, s0;
2 v* e. |# h7 T7 b* s/ c1 V //out declared as register% Y; j# X3 a# N2 ^. M; \( H
reg out;; L2 |1 L' ^$ a0 ]! ~% [; s7 h% m" I
) X% V5 M) c) o$ \, Y3 [ //recompute the signal out if any input signal changes.
5 c2 l/ o/ x( K4 D( T+ H. ^ //All input signals theat cause a recomputation of out to occur must go into the always@(...)
$ v) T) i1 W/ m+ N2 Z4 w always@(s1 or s0 or i0 or i1 or i2 or i3)
7 |/ _+ Q) T# {9 f( g. l begin( X2 K8 y9 f, T% P. }; i
case({s1, s0})9 j6 B1 ]. _% n& t$ @
2'b00: out=i0;* i# y' C8 o _$ B+ E
2'b01: out=i1;
# S+ b2 e1 ?/ _1 p 2'b10: out=i2;& M! m0 _! P/ U6 a
2'b11: out=i3;/ d* N5 ~ U0 q' L
default: out=1'bx;4 d" J! l* Y9 W
endcase2 }$ r* s5 l3 d, ]" Y
end
. B. y4 [1 h1 Q3 E. @) ^; z4 k% P: g6 _1 Q. @$ @
endmodule, l9 u# u! z, M; Y8 X3 F% l
=======================以下是test bench==========================: l* O! e7 G. }" M( e1 G; E8 R
module stimulus;
5 g8 J! |$ }, N. U$ y5 X1 x2 h5 b) Z1 B [; d9 ^
// Inputs+ A' V, c+ n& L: C' ` {/ H+ g
reg I0,I1,I2,I3;
. Z6 G/ {( t- I/ R4 j+ r reg S1,S0;
* |/ t# x5 k, S# D& S // Outputs. J* C) q6 J) ^, m! L. i! P/ t
wire OUT;% D1 {3 c7 ` x, {
( c9 z- V& r' g" `5 @% f: Q // Instantiate the Unit Under Test (UUT)
6 g/ ]# w! E3 `5 G' ^' L* M mux4_to_1 uut (# L1 o/ z) h6 X3 i3 v7 m J) s+ H
.out(OUT),
8 r4 U& L* i8 |- T2 n- `! G! h9 n .i0(I0),
1 \9 @" y7 X; w$ y8 d .i1(I1),
' K" ]% ]; a- R& I .i2(I2),
8 @# x0 o' G; ~3 m8 E5 v .i3(I3), / L. K' E R; V1 b: S' C# B
.s1(S1),
# f+ s; \9 V v, V! H& d! s$ ?2 S! m .s0(S0)$ S) b5 F6 k- G& s
);
# u7 l" \: n+ {% |" J$ |- G) \; M( A- o/ {2 {& H
initial begin( p4 V0 Q) C6 _( `
// Initialize Inputs
8 r! I' s. S. K I0 = 1;+ n; O4 d% i4 M& H+ H( J1 }- l$ p
I1 = 0;
! j+ {5 ^' k; i I2 = 1;
! I" F( B3 n( b I3 = 0;
4 C0 i; _/ Z7 f' V0 C# X
4 h" X8 G- Y9 d% _- W #100 $display("I0=%b, I1=%b, I2=%b, I3=%b\n", I0, I1, I2, I3);+ }0 K u1 X, V6 E9 j9 b
//Choose IN01 Z& H8 a, w0 U0 A4 B1 \
S1 = 0;S0 = 0;$ G; x! L5 R' l* ?; ~$ w0 P9 z4 f
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
. S7 Y& K4 o8 y9 M: b6 Q( ]* a //Choose I1
$ G0 v! C9 B) A6 |& \) z) A+ Y! p S1 = 0;S0 = 1;
, A$ u$ q l0 L #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);2 q" d3 ? I. D' \( N2 t* g g z
//Choose I2
( A# `7 ^5 P# [7 K0 A S1 = 1;S0 = 0;
0 e0 @/ y9 l5 @5 \% j1 P #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);' ~3 |* T* I+ h- }0 @4 U
//Choose I3) c: V4 i6 r: s! T5 ]# i
S1 = 1;S0 = 1;5 r# N) P0 r8 G" A7 R, T
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);2 D" l1 z8 s- S& r u7 O
% @2 m5 {/ s& D0 I
" v J" l2 @" b8 @, L6 W end
$ U2 Z, c6 n: ^2 b, R( l, \8 V' f( z U2 o) t+ W2 u" j7 h1 r
endmodule |
|