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小弟寫了一個mux 4 to 1的verilog code用xilinx + modelsim SE 6.1f
8 {7 N. J' f% p& X2 p( u# Q* l跑模擬
$ Z; f( _3 E" d0 f/ C; ]可是跑出了的波形都是high Z跟unknown
8 A; @! Y4 e6 M1 `; j也就是訊號資料檔沒灌進去1 }0 N4 s- k' A8 ^
想請問各位大大
, }# Y h" P! N我該怎麼修改這個錯誤; J! Z6 l0 E8 G& B
# M% c* g& T5 ^* c2 M* `/ O
=======================以下是verilog module code======================
, R2 A3 c2 u5 u5 s3 smodule mux4_to_1(out, i0, i1, i2, i3, s1, s0);# X; }! b5 _! W
output out;
. W0 H7 `4 R: K input i0, i1, i2, i3;
9 P& a# v( z. w, ^+ g4 ~/ B input s1, s0;* F, D- b( T6 A+ W
//out declared as register
) ~0 K, \# q- _5 S8 Y reg out;
% v3 E; W! { T7 R- j : l& t8 K8 l9 Q4 ?6 i& l' n3 ~
//recompute the signal out if any input signal changes.: S* I- t# H0 c/ s. l
//All input signals theat cause a recomputation of out to occur must go into the always@(...)4 A' H! P* u+ V* ^" @1 K
always@(s1 or s0 or i0 or i1 or i2 or i3)- s7 l1 M2 N( b) e
begin
/ \! G; s P1 }* t6 D case({s1, s0})$ P5 p. F6 {$ N& R+ r% n4 B; N" Z
2'b00: out=i0;
6 v+ R/ M3 U2 R 2'b01: out=i1;& Z( V, L, w0 u0 z6 }
2'b10: out=i2;
" S5 e: ?; h( h0 p 2'b11: out=i3;1 E3 r5 o/ }/ E$ z G
default: out=1'bx;
7 ]0 B6 a( m6 u* E5 v- h9 v endcase
* x) A0 G8 {, G# R end
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endmodule4 U/ `& C. L4 `* h$ H6 b+ ]) P
=======================以下是test bench==========================
' x! _, v: x8 `module stimulus;
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, i9 u% X E- B( ~' ~" k5 m // Inputs
( l, ]1 \1 p t* a: a reg I0,I1,I2,I3;. C+ M) G, Y* `
reg S1,S0;: z$ U% m' J; ^4 t4 }$ M: c
// Outputs7 A- Q+ R6 a# L+ j# }9 y5 _
wire OUT;: S3 M3 b+ k0 S- P
% [/ z9 X( R; Y7 x9 @) b, j; d
// Instantiate the Unit Under Test (UUT)! N; u- K9 f/ N+ Q
mux4_to_1 uut (
' ?8 D% T7 H% P& K .out(OUT),
+ n5 z5 t% B$ Q" n; A .i0(I0), ( o$ N2 a; f* y% G \
.i1(I1),
& K$ K$ Y) r3 K7 o8 T" H .i2(I2),
1 ]1 P4 ^0 d/ F .i3(I3),
- z& I/ y9 p. g) e8 v .s1(S1),
4 |. L( n( p- ]3 [& Q .s0(S0)8 Q' p: s: p7 \% Z: d% U) f
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1 b2 s# m" I$ X initial begin1 S& J" n, Y$ e, P$ n
// Initialize Inputs
8 c+ Y9 a) E5 w$ {# k5 J; X* C I0 = 1;$ s$ f2 Z. @3 p4 k% J
I1 = 0;
- B# ]& ?% s0 v# e9 P I2 = 1;. g; g8 d" w8 a F% |/ l/ u
I3 = 0;
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#100 $display("I0=%b, I1=%b, I2=%b, I3=%b\n", I0, I1, I2, I3);
7 t9 @0 s# z# `- I7 T4 e //Choose IN0
0 Y1 q& |! u$ b3 N! u9 L1 V& j S1 = 0;S0 = 0;" O, B* D5 Y) ]5 N0 S
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
9 s* s5 _; x: H6 _4 ? //Choose I1
$ x) I4 @( N1 \. G S1 = 0;S0 = 1;
3 f" }5 G2 Q/ }6 ~ #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);& X- X; Z; ^: Q# a$ J( C% \0 E
//Choose I2
! e2 J8 R: N7 D' Z, Q S1 = 1;S0 = 0;
5 g1 t+ C+ ~1 h1 z #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);! H$ z1 G5 n i+ E% s$ ~& i
//Choose I3) j2 p- U1 ?$ Q4 v8 b Q& `; k
S1 = 1;S0 = 1;0 _2 S) ]* b. D& a2 e
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
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9 K- [9 S8 f- j$ c v& F end1 |, y4 H F# `! Q% V
& W F( G7 F3 B: V! Q4 @
endmodule |
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