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小弟寫了一個mux 4 to 1的verilog code用xilinx + modelsim SE 6.1f. ^$ ^; v$ ?" C5 P' b" ]6 N
跑模擬. ]3 p, U3 Y5 d2 b' d0 ?
可是跑出了的波形都是high Z跟unknown , c; l U- ?% \2 j0 {
也就是訊號資料檔沒灌進去
4 w7 J9 P* ~- I, c9 W/ C7 @想請問各位大大" ]' [! I* g, h9 x; A3 \
我該怎麼修改這個錯誤
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=======================以下是verilog module code======================
( v0 }; l8 b" F7 b0 r. p8 Qmodule mux4_to_1(out, i0, i1, i2, i3, s1, s0);
8 E7 }' V, h) I* N( E7 i. l output out;5 }# ], o2 K4 e! M& |
input i0, i1, i2, i3;. S% R; u4 d+ m: q1 F: @2 p
input s1, s0;
, {$ b1 d. T4 X! w //out declared as register( P% ^. g( }. i z) R! ~+ k
reg out;/ _8 B V# I6 V! l4 e0 d$ F
0 Z- u1 x3 s2 `5 t; g) y( I //recompute the signal out if any input signal changes./ I. y( ]* m6 n4 D. C
//All input signals theat cause a recomputation of out to occur must go into the always@(...)
k9 K7 c5 V4 D. u- ?- i& } always@(s1 or s0 or i0 or i1 or i2 or i3)9 r8 w" Z$ l, E3 V: s9 L
begin5 Z! N3 i+ P8 H7 `1 _
case({s1, s0})
9 F5 f/ Y0 D# C 2'b00: out=i0;
5 z% Z# m5 `4 s' ^! Y! _3 r5 h 2'b01: out=i1;
+ L, G) y* K) e) F+ [ 2'b10: out=i2;
( h- @) h. R: l: A. n- Y 2'b11: out=i3;
1 Q: P) y" _6 a' n default: out=1'bx;
" ~1 l: {% M9 c, l( X' H- k endcase) _* @1 S3 S* w0 B
end9 a' \" W3 O; O$ s
- H4 d2 l0 A( x. D7 ?; ]3 Mendmodule
" p; |) ?7 } Q6 y/ K) V=======================以下是test bench==========================0 T$ b, T7 t: r) L& @5 x+ @4 u
module stimulus;* Z% \6 K( J% C* n. p/ P
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// Inputs3 w; J' k, i; [
reg I0,I1,I2,I3;, P6 l. U% ^3 Q4 R$ w' `
reg S1,S0;& G. i& u* n7 X# S! d
// Outputs' ]: A: Z( |% |0 G- l
wire OUT;
$ O: _. i; C& ?$ e }3 L
: A* y2 V- _5 { // Instantiate the Unit Under Test (UUT)) l: z9 r8 Y) Q' L
mux4_to_1 uut (
f9 \1 d- {0 S* R e .out(OUT),
( X# h' |8 v1 J- K# t# \8 l! z$ g1 o) p .i0(I0), & n* f% [+ H+ s4 r0 y
.i1(I1),
; ?6 q( \' r8 C& d% T .i2(I2),
& q+ ~5 N+ ~+ V( Q* X .i3(I3), : H8 Z8 r8 J' G5 u% J5 a F6 g
.s1(S1), 8 R* {. g' ^2 z% Q$ W# G
.s0(S0)
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initial begin+ x# L2 Y- `! R
// Initialize Inputs
& @3 e0 r* ?% {; U* l; H I0 = 1; r; R1 s0 d* u, x) I% z6 s
I1 = 0;. K3 c1 Z6 V' j- |2 i( \9 v- E
I2 = 1;8 P9 Q6 _0 f8 e* z5 h8 u6 P; e
I3 = 0;) m1 \" C4 q' [) S* _# @
- g' \8 m. a$ e' u #100 $display("I0=%b, I1=%b, I2=%b, I3=%b\n", I0, I1, I2, I3);
+ _" _) q, t$ q% b& u f% I$ u6 @ //Choose IN0
! }+ F9 W; f6 z; |6 b S1 = 0;S0 = 0;
6 A* v# R$ u" w Y/ U #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT); D5 }9 V0 X/ W, ?1 G: n. Q- K
//Choose I14 a: }( C6 b) G# N/ k, A4 }
S1 = 0;S0 = 1;
# x7 k" W2 `' p, |7 v0 q #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
" L* K% {( o0 g* O. f' n6 @ //Choose I2
7 N' K4 L% ^& m S1 = 1;S0 = 0;
# A# L3 `, k+ q- q3 U, r #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);4 L6 C$ m7 q7 N |8 u9 q+ R3 Z
//Choose I3" Q5 ]' n h8 C6 M: u, X& X
S1 = 1;S0 = 1;4 Y* P' N+ I0 F% ?2 o
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
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end& @$ X( _/ j r" h/ T
, u5 x/ u" z! d' y y/ j3 Cendmodule |
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