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小弟寫了一個mux 4 to 1的verilog code用xilinx + modelsim SE 6.1f
5 t! Z5 b* Y6 u- T8 g/ `跑模擬- e5 }, a8 A% T( H, P* B3 ^
可是跑出了的波形都是high Z跟unknown # }, R" n2 i$ Q
也就是訊號資料檔沒灌進去7 b/ K3 n. x. E" d# p
想請問各位大大0 D* w$ J7 ?7 l
我該怎麼修改這個錯誤
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* V- W3 [' S; h* ~' k=======================以下是verilog module code======================
6 ^6 V" r A) |4 Emodule mux4_to_1(out, i0, i1, i2, i3, s1, s0);
8 X# x7 `* ~' z6 F2 x$ x output out;
- k/ r6 y; b8 }+ @1 {/ ^ input i0, i1, i2, i3;
- ?1 o6 H6 M T5 n7 }6 w% c, Q input s1, s0;8 v, r6 C6 O) ^ N- D! o: e
//out declared as register
+ e1 t a" o3 F/ ^0 Z: ` reg out;& p2 ?9 b: O( b: w: X) u
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//recompute the signal out if any input signal changes.) k& p# Z, R( n
//All input signals theat cause a recomputation of out to occur must go into the always@(...)
0 C' x o) ] B/ @ always@(s1 or s0 or i0 or i1 or i2 or i3)
/ m4 y# D0 n1 l! i9 d0 p begin1 ]' p V, N( A" D
case({s1, s0})4 F( ^+ ~1 H4 G l
2'b00: out=i0;
4 o: s) J0 E& v& ^ 2'b01: out=i1;9 ~4 G" \3 u4 O+ A) a
2'b10: out=i2;
/ @4 Y; M, g& m! N' c4 c/ O0 [ 2'b11: out=i3;, I8 O, D5 w3 r5 n9 b) _1 C+ l
default: out=1'bx;
; D4 d/ R" Z# F, D N6 H endcase# H2 _4 W; a3 {& C% F
end' c- u+ y7 ^: ]2 Q+ t0 G
% Q) h% t& P7 i6 u: j3 Pendmodule% i+ L D- w/ O! w
=======================以下是test bench========================== N2 Z$ t' i/ N# a f
module stimulus;1 T2 W6 C9 Z) G; e
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// Inputs
G+ r7 m& L, y; i reg I0,I1,I2,I3;" n+ r q9 Q/ {% ?1 V! o- L& G
reg S1,S0;
0 V! q8 e; q! N3 L. A // Outputs
+ R1 f- n" E/ G% c& l wire OUT;
+ }0 J! {5 h6 J7 N& ]3 W
/ w# m7 o5 X9 X' }* D r // Instantiate the Unit Under Test (UUT)
; a. r* ^* a. g. g! o mux4_to_1 uut (' r) |4 n* S! G! ^3 p: p( O6 l
.out(OUT),
r; L2 x" x4 v0 X& a .i0(I0),
! M3 @ N9 O$ j4 [ .i1(I1),
T6 l" B9 i f; Q .i2(I2), 3 k# w) k9 b9 G) @' L& A8 j
.i3(I3),
4 f5 ~( J6 B v( v, e .s1(S1), ; Z: V$ C6 t1 n2 N: [, B" E
.s0(S0)- G! j+ U, [0 k6 A/ k. V% c
);
8 Q4 W( v% E& i
6 Q" `9 X# S7 F initial begin
* m' ^5 Y i9 \- |, }- ^% D // Initialize Inputs
3 u8 E9 M$ c6 V6 b I0 = 1;
8 {8 V6 x# T7 u$ R I1 = 0;
& k: T4 _- _! C3 A" c7 G2 R I2 = 1;
F, W9 D1 Q M9 e0 T- |/ |) X) } I3 = 0;* |) ~1 V9 t! K8 T) D
- {( J6 r8 R) o8 J6 M5 V& T. \
#100 $display("I0=%b, I1=%b, I2=%b, I3=%b\n", I0, I1, I2, I3);, ~% |3 L+ ]3 s$ Z; e9 J& @
//Choose IN0: C) q& l" u5 S7 w8 H, v# Q. \2 H1 p
S1 = 0;S0 = 0;
* _" H# v- m7 M6 t/ o$ X #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
( o. l/ D5 m& D' F //Choose I1' N7 q4 l& a3 P! Q+ }, n; b
S1 = 0;S0 = 1;- Y( b+ G4 k7 B) o
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
$ G' F$ h0 V# M6 b //Choose I2. ?" `$ q0 A4 V7 N2 i+ l! ~( y
S1 = 1;S0 = 0;
' V0 U7 \# U& E #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);2 t1 h* \5 Z9 F# w3 ]+ ^# o. C
//Choose I30 X. C, x# n3 R) ~
S1 = 1;S0 = 1;
, k; m$ S9 t8 b1 O9 I; s, d1 E9 y8 g #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);: Z, ^6 T, D6 f4 t; s4 }3 j
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, z! b) ]: n( W4 p% \0 V end2 K$ n) O* \, n# t7 h4 ?+ f
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endmodule |
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