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小弟寫了一個mux 4 to 1的verilog code用xilinx + modelsim SE 6.1f
8 N3 e8 s) p! C& I: y6 c1 z |跑模擬 D* K k) |; `5 h$ H1 P7 g
可是跑出了的波形都是high Z跟unknown / Y9 G: d2 p" q% f1 E @
也就是訊號資料檔沒灌進去
! u5 F" ^% o. S/ ^想請問各位大大
% E4 R3 F) \$ ]) v我該怎麼修改這個錯誤
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=======================以下是verilog module code======================
" ]# `- {$ r* V' \8 y* mmodule mux4_to_1(out, i0, i1, i2, i3, s1, s0);
' R& ^: i5 Z. N* {( N output out;
& U: |- w( ~$ P/ V" r: ^6 \% ~ input i0, i1, i2, i3;
9 f Z, S) a8 t D6 J1 z input s1, s0;7 S6 B4 K+ s; D' m9 N
//out declared as register
0 W2 Y, {) t, Y& M9 ~. u3 [ reg out;
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//recompute the signal out if any input signal changes.
2 y; A0 v7 F$ o- k //All input signals theat cause a recomputation of out to occur must go into the always@(...)
2 C1 [- e" A, V always@(s1 or s0 or i0 or i1 or i2 or i3)" ^6 d/ W! p# m" b- c9 s
begin2 I: S* w+ \; r7 L0 O. t. g
case({s1, s0})
/ p$ ?# Z1 ?/ H, V/ ~+ I7 [1 g- M% U 2'b00: out=i0;
+ ~3 I/ r+ X U8 c 2'b01: out=i1;; {& D- X3 g7 s
2'b10: out=i2;
0 ^5 b' z. [7 K6 Y/ ?6 u- \$ x 2'b11: out=i3;
# o# a) U4 ^, {% j' h4 U+ E default: out=1'bx;1 |. }! n* @* f7 A
endcase
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endmodule
! Y0 q4 e( ` L- k- C1 H8 ~=======================以下是test bench==========================
& d! o9 I, N% t1 Smodule stimulus;5 V& q9 y- [* J( j7 ], X
. C; E7 J) z' q$ [ // Inputs
8 _+ A" e. E, d reg I0,I1,I2,I3;4 w& R4 j B& x3 |
reg S1,S0;2 [8 ~( c8 X' U: H' t3 T
// Outputs# c O6 {" z% }7 x! y
wire OUT; t6 B% c9 q) C' k
3 {( G% {% V7 x3 ?5 Z // Instantiate the Unit Under Test (UUT)
- |- n( _+ c5 q' b; j) @. M mux4_to_1 uut (
6 m/ n) F5 ? C, ]$ P .out(OUT), / }: u7 T8 z( j) \9 T2 [ k
.i0(I0),
: U( t4 R* G, Y .i1(I1),
$ r. o0 n9 [ k t' ~/ E: m .i2(I2),
! r s4 u. c1 M- n .i3(I3), " K; P4 i. t0 w5 Z& J$ ?5 {3 Q
.s1(S1),
1 @& ?4 l8 `8 x .s0(S0)
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& d8 ^6 C6 Q: l initial begin
2 g( |+ b+ {: _9 X5 s // Initialize Inputs
% @3 h4 ^1 s8 Q% u; P# p I0 = 1;
! Y7 z# X& ^& n( u/ k# t! O$ C I1 = 0;
5 R% {. `; F2 L, q5 E I2 = 1;
$ {3 w3 h, n; O( f( K2 }$ a7 _ I3 = 0;
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#100 $display("I0=%b, I1=%b, I2=%b, I3=%b\n", I0, I1, I2, I3);
9 o3 W4 {6 c9 W! K2 d //Choose IN0
# C4 y: a$ q$ s1 h S1 = 0;S0 = 0;
; {7 C! k! B5 }1 l" z! {8 t #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
% ^' F1 u; H2 R& z) P' f9 P //Choose I12 D# c4 @% ?8 n! F5 _
S1 = 0;S0 = 1;
+ m: L- v: w5 D K- _ #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
2 X/ B* f- a2 r) V //Choose I25 A9 ^* k+ q. K1 S8 Y
S1 = 1;S0 = 0;
8 g3 g3 G/ a- s0 U# ? #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);3 J! T8 J5 K! B
//Choose I3! w$ I* d2 u8 A: x; {. j
S1 = 1;S0 = 1;
, Q$ Y# p* `/ o #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
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end
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