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小弟寫了一個mux 4 to 1的verilog code用xilinx + modelsim SE 6.1f
7 _; N' L7 X1 W跑模擬) B4 ^! m) S# G" R: M* u) j6 B1 X2 Y
可是跑出了的波形都是high Z跟unknown # f4 K" i7 D- E0 z7 z# L( m7 N
也就是訊號資料檔沒灌進去. d% t1 d* f; U) z& R; P
想請問各位大大
% r, v3 O5 C. b! C. H6 S我該怎麼修改這個錯誤
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=======================以下是verilog module code======================
& v. z7 U* B% lmodule mux4_to_1(out, i0, i1, i2, i3, s1, s0);
8 U% u) ]; y5 c, O output out;7 b: f+ x' y& ]+ {9 G3 M& o
input i0, i1, i2, i3;$ [" G# c% a- C' X4 H# ]
input s1, s0;
5 C- C! a4 l J" ` e! Y //out declared as register# ]6 g1 H7 ?; J! v) X5 O4 i( A
reg out;! u8 b/ W0 U( Q0 B$ G7 z$ V9 {
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//recompute the signal out if any input signal changes.
3 J9 {# _, k. n+ o0 g+ M" v. t //All input signals theat cause a recomputation of out to occur must go into the always@(...)' f8 c4 C; p* Q( q
always@(s1 or s0 or i0 or i1 or i2 or i3)
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case({s1, s0}). J1 M/ s; s* g/ N$ K* E3 s7 D! Q
2'b00: out=i0;+ v# @/ M; r% ~: N9 X& @9 T
2'b01: out=i1;7 g. k* `4 m! E! Z' ^/ l9 W/ p
2'b10: out=i2;
) F9 b" K% [: T# x6 B1 z9 i9 M; f 2'b11: out=i3;8 C2 R0 g. k8 S! D3 o3 R
default: out=1'bx;# x) F; n4 ~( y+ Z! h
endcase
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endmodule
- Z: e$ C7 g. I: A- l. N=======================以下是test bench==========================2 q a8 I& @: ~* d9 _8 H
module stimulus;
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$ ~7 l' |( d) D6 v6 Q0 i( ] // Inputs
, C+ C+ t: {/ n2 D reg I0,I1,I2,I3;6 L# _' ^9 @" R, ~; w
reg S1,S0;
' B5 c1 A0 Y- T // Outputs
7 o' a; c5 m4 f+ V9 n wire OUT;
2 N0 f9 l" M1 h5 W j
% J4 u3 A, q3 I" E' d' i // Instantiate the Unit Under Test (UUT)9 A x; {# {7 y& o2 X& a( D A) I
mux4_to_1 uut (
: J/ y% ?! K8 x+ o- y .out(OUT),
4 I: I3 Q B5 C" ]4 s .i0(I0),
I- S) N% Z4 A+ p .i1(I1), ! E. _- f. x* o
.i2(I2),
( @" p' p, t4 b, G/ n .i3(I3), " c4 v% g, Y$ ? K( f0 y9 v
.s1(S1), 0 Y6 a9 s1 t+ v* h" l' z5 A6 p) V3 K
.s0(S0)
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4 t. f/ K. i% P$ j: j+ t initial begin
3 p# X7 _% B1 q3 w: i' [; }0 O6 b0 F // Initialize Inputs/ g+ A) E" L4 n( [: U
I0 = 1;
a: {+ p6 U8 u4 C5 l- a5 N I1 = 0;
5 c0 u: C$ }3 M! W- j I2 = 1;) p* y( N/ O% }6 T1 g6 |' _8 [% p
I3 = 0;
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2 g& D7 q J" j _+ L, t #100 $display("I0=%b, I1=%b, I2=%b, I3=%b\n", I0, I1, I2, I3);
* l8 T* _4 b4 d% r6 v9 x# H9 |8 n //Choose IN0
7 a5 J H2 b+ f, S S1 = 0;S0 = 0;( L# p0 \6 u0 `3 U* ]. C
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
I+ p% S5 Z$ f/ H6 F) \ //Choose I15 M# ^ w% q3 z) L
S1 = 0;S0 = 1;
7 D% r% |9 m5 J8 Q3 T& B+ n8 n& u7 S #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
/ A I- d8 c7 Q& z. `% k2 \2 s/ f- b //Choose I2
% T$ r- H `2 F/ R' n' q: R S1 = 1;S0 = 0;* m v( W) |3 x* N* r) p$ T6 ]& P
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
# i6 E! u/ G, \! P+ I. N //Choose I3! l: } G0 ?/ ~: g" P% Y
S1 = 1;S0 = 1;, T' t7 ?( i; `. O& n
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);- c( q! I% F% N* j
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. ?4 W, }6 r7 V3 n" Z; u; Q0 w ~ end
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endmodule |
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