|
小弟寫了一個mux 4 to 1的verilog code用xilinx + modelsim SE 6.1f
4 A1 W- j+ Y* r8 _1 u跑模擬
# C$ y2 z& ~* K可是跑出了的波形都是high Z跟unknown 8 {2 ^/ V% t$ G
也就是訊號資料檔沒灌進去
- d% D: r! L& ^9 l2 j% A* W想請問各位大大& W$ v, ], Q! U" w3 L6 K2 U: B
我該怎麼修改這個錯誤- @ L& ]$ W( I3 G. J! f
k4 c. U1 X: z" K% [=======================以下是verilog module code======================
. M8 s( O; B8 w9 {module mux4_to_1(out, i0, i1, i2, i3, s1, s0);, _+ l* K9 t6 Q5 F/ B! {0 g( n" \
output out;
1 R V$ ]2 ^1 s; n0 @7 Q, `0 ?/ h input i0, i1, i2, i3;
! x$ u4 p" Q( e: h input s1, s0;
! {# {$ b' V1 T2 m n //out declared as register" y; F/ C% W. p
reg out;
9 J0 T: a1 n5 J+ R ]
) u$ y) H0 t2 j //recompute the signal out if any input signal changes.2 u. N- ~4 }4 d& q( ~6 D& q
//All input signals theat cause a recomputation of out to occur must go into the always@(...)
T- s0 S) r9 z+ u2 a. B) A* W* P, i always@(s1 or s0 or i0 or i1 or i2 or i3)
5 a, h6 X2 ]( n* L" t begin: P2 Z) x* g/ G7 F' H4 F% @# s5 y
case({s1, s0})3 v. ]0 W% ^& @4 l& K# X) [4 z
2'b00: out=i0;
' ^6 x9 p* \9 g" A. C" G: J 2'b01: out=i1;" j$ D% y: b6 V
2'b10: out=i2;8 G. x1 y- J7 f, c7 G& o3 T
2'b11: out=i3;
5 t8 L7 }% n1 I/ q default: out=1'bx;
$ u- p+ ~' ]8 r endcase$ w- l2 p% U: d$ m9 J+ _+ k* U
end6 d& W& ^6 P5 c$ h v7 F/ _! |5 Z
1 S# |2 \1 F t0 c0 T. \0 {3 Oendmodule6 z: b. ?' ?! V5 x+ W6 E3 G
=======================以下是test bench==========================; |' N' R, q# \7 G6 Y8 x# w+ z( U
module stimulus;
+ z/ H" x: N- T$ X1 s/ w' x9 P& }+ I7 M( P$ H" W) J. Q
// Inputs2 \/ ~7 d& T! h$ J
reg I0,I1,I2,I3;
) `, B* U; C m, B- H/ n6 m reg S1,S0;
0 F* P0 P2 A7 B# p% j* g // Outputs0 a2 H) f/ A0 J7 d! Y1 c, H6 P
wire OUT;' K L& `9 F' s
o% w0 n- A T# H( k. F7 T3 d, @ // Instantiate the Unit Under Test (UUT)" R$ K! J0 f7 m7 C* d
mux4_to_1 uut (
6 y6 U; k5 S, Q0 N .out(OUT),
, W9 W$ s% G$ T1 S# [ .i0(I0), 0 F$ V0 H% _6 N$ @. m
.i1(I1),
" U8 y( g8 [( @; S) R% R2 Y# S .i2(I2),
6 \" K( F) I3 e% w: J .i3(I3), 7 W6 E' U* l- Q( {) x3 M0 [
.s1(S1),
$ A2 Y9 D! [' T a' n5 f+ K1 B" A, n .s0(S0)
+ b4 Q1 D+ s8 q" v6 ? );
! ]% |. Y9 p# _% ]
, \& k ?- E& K. u& [+ b8 m initial begin
, c! a: Y; V1 F6 d/ w: j/ r9 u // Initialize Inputs1 W1 e, x) M+ T7 p- K
I0 = 1;( T/ }. z: f& _8 H; G/ E
I1 = 0;
2 |5 O/ ]: x3 q1 n* y$ a I2 = 1;
8 _- j! U8 b4 k' l. p8 P3 P* r I3 = 0;. k( t- H8 M* H) j5 |
% V5 O, W9 f- e
#100 $display("I0=%b, I1=%b, I2=%b, I3=%b\n", I0, I1, I2, I3);6 m+ m2 ^7 V0 j6 R8 e
//Choose IN01 s8 [, N7 I2 @" I! i, N
S1 = 0;S0 = 0;+ M6 o/ {* d& u, D( T4 ]2 J/ a
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
5 |; j& Y2 I$ L! p9 M& M K) ~ //Choose I1
! }3 ]' ^% C, A9 C' m, Z S1 = 0;S0 = 1; ~7 d- x& h& E- ]# a% V$ k6 u
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
* J6 {6 n! G6 f& { //Choose I2
2 p# K j2 Z5 H; \, B3 b- v. S S1 = 1;S0 = 0;
w* C3 H% a3 n/ P* B. B) u# [6 } #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);. z j" ]2 h" g6 {
//Choose I3
8 E, Z3 a9 R* F7 ? S1 = 1;S0 = 1;
; y" M+ A$ P9 F/ ], e8 i. [ #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
+ A. o7 t i3 p# w0 h+ e( X* t; g2 h2 \0 m. o
% C; `/ \: m& _ end) i( H/ k- ?6 t1 v
+ D) r0 w* F z" \' }endmodule |
|