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小弟寫了一個mux 4 to 1的verilog code用xilinx + modelsim SE 6.1f
8 H7 F1 a4 | f9 J跑模擬) j- v# ]0 v% P* O, O: D
可是跑出了的波形都是high Z跟unknown * [# _) ?: \, j. x6 J, r
也就是訊號資料檔沒灌進去; A: ]5 b+ ~! [) d- I( r
想請問各位大大8 Z6 g) Y( M4 u1 V. W$ w
我該怎麼修改這個錯誤0 K# D' L- Y# z7 w, {3 t, X
% O& d7 D2 O' C$ E% @8 O+ b=======================以下是verilog module code====================== e" n) ]2 a4 B) N' E' C
module mux4_to_1(out, i0, i1, i2, i3, s1, s0);
! n" L* j% d( _0 |( |- Z; H0 D8 A output out;
% i, P* J/ z' U$ z input i0, i1, i2, i3;) \; K( ^0 Y2 ~1 m, P* F% ^2 t# C
input s1, s0;8 y! j" Q) Y* y5 R* a' W! z5 H: B
//out declared as register J/ T7 ?5 o7 }5 f- J' k
reg out;
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4 ]; Y+ I% ^ n //recompute the signal out if any input signal changes.
$ J8 @( E* x* s* D' n2 N //All input signals theat cause a recomputation of out to occur must go into the always@(...)
" O* u, r% W. M always@(s1 or s0 or i0 or i1 or i2 or i3)* i k% E: l0 f6 _) r: D
begin
3 N* }: {; g) U n( K ^; X0 C% e case({s1, s0})
; m' w* w6 E7 G" [8 b& O- E( T 2'b00: out=i0;
# I, `0 P6 R) _1 [& Q 2'b01: out=i1;
t$ G' _7 Q, B# J9 L0 Z$ N/ e 2'b10: out=i2;
/ R8 B. G, h1 W 2'b11: out=i3;
( q/ `) j: E! c( r) K* r4 G: C$ q) V default: out=1'bx;
+ w9 F! g% p4 b9 F) P9 b endcase% ^ a( Q( G& {8 v# F; t; d
end, C7 e2 I0 t, c$ \2 i/ o+ {% M
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endmodule
/ Q( q+ j8 m( T8 `" n4 C2 V9 |0 Y=======================以下是test bench==========================
' n) W. t+ D1 r% G! Nmodule stimulus;
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" S) D( U( G$ q5 U: e* p // Inputs
" K8 Q; ]' e$ Y& f D& u reg I0,I1,I2,I3;
9 d+ R) K$ r/ I( W1 J4 U j reg S1,S0;7 S. v) f3 D4 N0 b
// Outputs7 G; Z( [ S5 d2 O0 |/ C' `9 A
wire OUT;
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, N( @0 N7 T, I/ I6 p // Instantiate the Unit Under Test (UUT)% |0 g1 `. s( t4 A
mux4_to_1 uut (' Q$ s: p$ _) p2 x, }% X
.out(OUT),
' o( d- t( K# x+ [- k B% c$ x .i0(I0), c3 O( c$ Z- S0 {5 N; A! m
.i1(I1), 5 I) P3 I4 c, W
.i2(I2),
2 }4 k' {+ _* v .i3(I3), $ @! M8 C! R/ S
.s1(S1), " q/ F) P1 ] T- i$ S9 @2 e& t/ B% u
.s0(S0)1 p% ]3 ]" T) A6 {4 Y
);
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initial begin1 D( S% b* a. H6 R! y
// Initialize Inputs
9 e5 e9 E/ v' X; _8 [ I0 = 1;
4 X( N: u i/ Z0 v, Q I1 = 0;
: y: ^$ o+ h0 {& j' P5 A I2 = 1;
; X b4 E- {/ G) v+ R6 [* d I3 = 0;5 z3 L4 w% I0 T
1 ]1 e( m8 R8 q9 D+ R #100 $display("I0=%b, I1=%b, I2=%b, I3=%b\n", I0, I1, I2, I3);) r9 g. y* }- ?* J: U# `
//Choose IN0
4 q+ i" T" K* b! w2 x/ B S1 = 0;S0 = 0;% {4 L* P A7 N0 A p
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
2 O# L8 t1 c1 P1 M //Choose I10 v* |5 }4 A2 L) Z* Y; ?
S1 = 0;S0 = 1;
. k- D4 G! m, y" O #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
& c& n* p5 s6 f9 ]6 D- E- g //Choose I2+ q% R; R/ ^' H! Z; o1 `
S1 = 1;S0 = 0;$ Y; x0 @/ q* U4 j% [ n* l) J
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
" j, c4 H8 w, F3 L) b. ]- N //Choose I38 \& E7 R6 o5 v! ?- D ]
S1 = 1;S0 = 1;) t0 V' E& S* n( J6 }& I
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
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end# c# h5 N& w: u* I Z/ N
$ o& T2 b* o! wendmodule |
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