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小弟寫了一個mux 4 to 1的verilog code用xilinx + modelsim SE 6.1f/ G" M1 w' c( g g- ? S
跑模擬5 y4 [& Y; z4 v2 c- H) Q
可是跑出了的波形都是high Z跟unknown ! _* i- }! f( t
也就是訊號資料檔沒灌進去
- | J( B# E7 v: C) ~- @6 B想請問各位大大
& S/ x% U( E1 x ?6 ~) _4 j% H1 m我該怎麼修改這個錯誤
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=======================以下是verilog module code======================7 j" a6 K2 S% }8 B1 ?0 S
module mux4_to_1(out, i0, i1, i2, i3, s1, s0);
8 {" t' b) c6 ? output out;
1 u3 E- M. m# i1 Y* W, S' C/ G input i0, i1, i2, i3;- L- _1 m: X& S' j: d$ x
input s1, s0;8 K; Q U5 j/ C, _
//out declared as register
& o# |; u* ^8 _2 P reg out;# x4 i+ L9 K' J$ o5 m
6 l& l. e4 |; F" ]* f //recompute the signal out if any input signal changes.
( y$ O" {/ Z6 D4 z9 u& P, x1 O% n //All input signals theat cause a recomputation of out to occur must go into the always@(...)
. N7 i/ }1 V% |4 x" z always@(s1 or s0 or i0 or i1 or i2 or i3)
3 W. c9 v1 k- w4 M7 [$ }5 k+ _! e begin
4 Z' d, d; I5 I. |/ X% z case({s1, s0})& ]( J; }! U: E9 K& x2 ^* R. j/ ?3 S, }
2'b00: out=i0;
: d! \9 I; k+ { 2'b01: out=i1;$ u/ V* g9 T: \8 k7 U& ^: x
2'b10: out=i2; v2 l( A1 ~' d8 x" l: {" T7 Y
2'b11: out=i3;
( D; h9 \ l# |5 {! e2 K/ q% { default: out=1'bx;' g- z: s9 L9 H5 T$ S
endcase; T/ c2 {2 T! }& m; f& h
end+ t( J' F1 ~& b1 A
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endmodule
6 d% J: T) {# n) q=======================以下是test bench==========================1 a# E& J2 G6 S% p
module stimulus;" Q' i t( k, \$ l% E. N0 h
9 Z- o' X1 l8 q( o8 S // Inputs% ?$ w9 E; M" t& }
reg I0,I1,I2,I3;
}+ j" ?; I; z* P3 ?) v reg S1,S0;
( _% _3 ]# q0 o% d // Outputs5 W2 ?( m- K: @0 x) C
wire OUT;
% m9 j% x/ g& [6 r
; j+ ?3 e# u# B; C. ?$ B/ Q0 s // Instantiate the Unit Under Test (UUT)/ K& d( q9 j% T# j
mux4_to_1 uut (
5 x/ |# r/ K/ ]- b, L# n% m% ` .out(OUT), i- v; F( s4 r7 J
.i0(I0), $ T# G/ K$ N( [. Q: }' c
.i1(I1), 4 ~6 W% W$ m6 S5 n$ a% X- M+ h
.i2(I2), 1 J. m0 t7 N6 M s1 k
.i3(I3),
' C0 k* H5 m+ z7 p9 H9 e .s1(S1),
1 A* T. w! h$ B4 c2 X .s0(S0)
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initial begin$ P( E7 {" q8 c( O# M" n
// Initialize Inputs
* J5 p4 p/ {* @% S I0 = 1;
4 `/ b8 N2 ~3 C; \0 R4 w4 P I1 = 0;
; y0 J e2 t; [$ _, y2 ` | I2 = 1;
. ^0 g( c& H9 u: h. @ I3 = 0;
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#100 $display("I0=%b, I1=%b, I2=%b, I3=%b\n", I0, I1, I2, I3);
/ p8 F# j' ^3 C* B9 m //Choose IN0
1 w) [! u6 h8 d1 Z( S S1 = 0;S0 = 0;( v& W! X, j- C9 F V5 W
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
5 h0 p* h, t Z/ g: C; j$ ?6 M/ V+ g //Choose I17 J+ V1 M$ h& U0 D- l( a! u- u
S1 = 0;S0 = 1;& O% ~/ h3 [/ g4 F. h7 r
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);( B9 Q9 }- R" H$ w
//Choose I20 O0 H" n% m L: S) V
S1 = 1;S0 = 0; {/ @1 O* A( \' a* s: @ z" C3 G
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
" R3 H4 Z5 s; Q% J3 M* W. U. h //Choose I3: N( T$ V: J7 q( |& |" N
S1 = 1;S0 = 1;% G$ C/ K" Q2 k; r( ~5 L3 s3 ~6 x# T
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
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# {) h% [/ k0 u! Z* L, i1 U! Y+ H end
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endmodule |
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