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小弟寫了一個mux 4 to 1的verilog code用xilinx + modelsim SE 6.1f0 h4 @: S6 }: N$ C& `0 ~; ?
跑模擬
, y; S' d3 n9 _, l% A( Z! g可是跑出了的波形都是high Z跟unknown - B, `5 {" O: l
也就是訊號資料檔沒灌進去
, Z# `3 _; e* ~想請問各位大大
% {1 N* N3 x$ c7 J/ f3 E我該怎麼修改這個錯誤
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# h$ c7 e; }! u; W, _8 z& {1 c* Z=======================以下是verilog module code======================0 ?0 [9 N+ B0 J8 }8 d: H, l
module mux4_to_1(out, i0, i1, i2, i3, s1, s0);* R% T0 b4 l, s, F, z9 E
output out;1 @2 m; k) ~- v4 m
input i0, i1, i2, i3;' b1 Y4 l) I5 c- v
input s1, s0;7 @0 w% E+ i) c3 A! f- h/ h
//out declared as register
9 {! V. G5 [* I w# p reg out;
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//recompute the signal out if any input signal changes.+ u* [( N/ v% a% J8 j
//All input signals theat cause a recomputation of out to occur must go into the always@(...)
) g! T, `0 \7 Z" O |% ` always@(s1 or s0 or i0 or i1 or i2 or i3)& t. h2 _1 C4 `2 \, i0 Z5 T6 [. R
begin T1 m: U0 |* S0 E3 C3 `: D: c+ H
case({s1, s0})! v$ K+ b4 b: T2 W9 a9 ?+ F
2'b00: out=i0;0 P# L) Q! h) i3 I5 K
2'b01: out=i1;' j* Y6 u" G. |+ k9 r/ G- [; J7 {
2'b10: out=i2;
& \7 D. T2 l+ L) x 2'b11: out=i3;
' l8 a) T% F, k" z- G2 e2 r, G1 d default: out=1'bx;3 _, Z( O a5 C- j- x
endcase
! ?+ s) x0 [* K+ L end
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0 v! S. F+ w/ M, s) Y; D3 z9 bendmodule( s" b9 A, Y# L$ n1 A
=======================以下是test bench==========================* h* J2 c$ A; P& Q# a) ^* P
module stimulus;3 V3 W2 ^! m# f: J9 @ b
+ H! M3 ?' i+ w6 x3 M6 f$ g // Inputs5 H# S3 E5 o; |: c# [
reg I0,I1,I2,I3;
7 K% g0 m* N+ L( U/ o reg S1,S0;8 `1 U4 S5 ?% G% F5 y8 |0 j
// Outputs
* L+ L2 W. n2 B! l( X wire OUT;4 X9 v- g/ k, p" z- [9 U1 Z5 U" Y
9 g) i5 F* g8 _7 j h // Instantiate the Unit Under Test (UUT)$ Z( }+ ]5 L3 v: w# a1 y
mux4_to_1 uut (+ _3 z* K% l* I( j% k
.out(OUT), % c0 v( |: e/ A/ c
.i0(I0), ' P' ? B3 g% e$ E6 a7 r
.i1(I1),
+ j+ }# o* e) t3 L g9 a. s# r .i2(I2),
) n5 l: c( ]' h& T7 W- A& G) W .i3(I3),
3 r3 G+ ^. d0 E) o .s1(S1),
' e* F1 u9 X# v, X; l .s0(S0), N: ]% G- T" C5 F
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. x: _2 B0 t# S8 p7 U1 l initial begin( |' X# Z* ]; j( A/ [
// Initialize Inputs
& b j% S7 I! C9 u2 U8 [- F, a I0 = 1;
8 t: Z. L9 ]) [% m. w I1 = 0;
9 b6 A: C# {2 n I2 = 1;
9 g& O5 [! b& W7 _. Z I3 = 0;
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7 j5 x3 G8 J% O0 c# f6 q; `/ N$ w #100 $display("I0=%b, I1=%b, I2=%b, I3=%b\n", I0, I1, I2, I3);/ ^5 o+ P; o/ H. r- W
//Choose IN0
2 p9 ^0 b/ B! p S1 = 0;S0 = 0;; l5 T# j% ]2 p% k
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);+ s5 l0 ]; O/ b
//Choose I1
3 h/ [7 d6 j3 k, i- U! g. ` S1 = 0;S0 = 1;5 S7 h% n# n9 U8 O
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);3 s9 ~0 h/ {2 |
//Choose I2
) ]" F+ g0 k2 W( w S1 = 1;S0 = 0;
2 J& S8 D: M' p! V2 m, ] #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);* x! Q6 T1 e0 Y. [' b% K/ S
//Choose I3
6 s- I* r* }! y& p" z2 F# ]& K S1 = 1;S0 = 1;5 l9 |- e& J3 P, y: o- {8 `( R
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);1 r% H! _8 f. t# f. D
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end
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, ]- |, k4 M4 T! g- Cendmodule |
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