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小弟寫了一個mux 4 to 1的verilog code用xilinx + modelsim SE 6.1f$ d: J4 {6 v! U6 a( p/ F% V0 L
跑模擬! m# ~! _0 A4 [' ^8 l2 z
可是跑出了的波形都是high Z跟unknown
6 g- _, I1 d! |( }也就是訊號資料檔沒灌進去5 q" o9 k. w& q8 q2 q" _4 J7 P
想請問各位大大; ?* ]+ a" J8 A# O& z
我該怎麼修改這個錯誤
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# Q: x4 y1 n* {( N=======================以下是verilog module code======================- v S" i' K, y" i- G& n5 a" X
module mux4_to_1(out, i0, i1, i2, i3, s1, s0);( ]9 W q; D6 \; O& M) F" X
output out;
7 ?- f% Y' _. t input i0, i1, i2, i3;. G S4 Z3 u/ I3 x! U
input s1, s0;5 i4 H- t! N) ^ w" T/ e2 |$ z9 D
//out declared as register
O" v$ z( ?" T! m5 Y reg out;0 s1 @' j0 l, o U8 j3 W
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//recompute the signal out if any input signal changes.
9 n M; ^1 q3 T6 W# ?& \5 G; b //All input signals theat cause a recomputation of out to occur must go into the always@(...)
% {, h5 F5 z: R% f9 \9 T always@(s1 or s0 or i0 or i1 or i2 or i3), P# x! J: e1 {0 c# T9 S
begin6 o9 _2 t, a9 |" b
case({s1, s0})# _& X" T) X: U
2'b00: out=i0;: j- w5 {; H/ r# |1 P) a: A
2'b01: out=i1;
2 ^, e0 e; M2 m6 s I5 Y+ X 2'b10: out=i2;
! _ U0 [* o7 @) O. r 2'b11: out=i3;
3 I9 C: f$ B1 z) W) r4 y: \, o' H default: out=1'bx;7 z1 N/ g2 K, w8 F% x
endcase
- {9 ?8 P8 m" D! x2 B end
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endmodule
4 m) I' `& k; b=======================以下是test bench==========================! z2 J; j9 w% y: L; A8 q
module stimulus;
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// Inputs$ e$ H* c9 A) t2 }& }2 h8 L
reg I0,I1,I2,I3;5 a% k+ m4 |. ~. x/ S1 t/ i0 h
reg S1,S0;
* j5 x* h W4 J // Outputs3 h- d: h3 E& L* a* u2 L6 j
wire OUT;' U t- N( W$ w. n& c
% e% ] X( k% \5 ]$ e1 X4 C0 h // Instantiate the Unit Under Test (UUT)
; D9 v- S0 L+ r+ v2 q2 w6 X mux4_to_1 uut (2 U) t/ Y5 Q8 e5 ?, j
.out(OUT), ! N: h* {% |; x
.i0(I0), , D2 M- b+ P9 f: r3 p1 ~8 v
.i1(I1), * y6 T3 k* E0 z @
.i2(I2),
9 s; M, @4 r- y0 R! r+ O, I+ m .i3(I3),
1 o ?# B7 a4 L3 Y' i' L .s1(S1), ( X5 C, k1 \5 k' A: q* z8 B: P9 x
.s0(S0)
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+ H4 ]/ z7 a8 a+ ~ initial begin
" H' C0 B, q4 W) U) U5 a // Initialize Inputs
$ N: I3 e. r! |3 b4 b2 X4 w) N I0 = 1;9 E# q) \3 N4 L: x/ _
I1 = 0;( g- w& E* D+ b @! _
I2 = 1;
, T" e. O m4 @8 d4 { I3 = 0;
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#100 $display("I0=%b, I1=%b, I2=%b, I3=%b\n", I0, I1, I2, I3);
7 Q5 U0 I) l2 _0 B# a3 e //Choose IN0 F# d& b- H& E- J
S1 = 0;S0 = 0;: l, {2 |3 V) {9 G1 O8 V# w
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);3 o# ?) U; `4 m0 q l. u
//Choose I1
, r8 k8 p7 R- O# t: h8 [ S1 = 0;S0 = 1;
4 W0 g( \( ~2 u+ y0 N #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);( J' I9 V; z( l9 I
//Choose I2
1 H4 R1 e: d% Z' a S1 = 1;S0 = 0;8 L% V+ D4 q# J+ z& b8 r
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
; H8 b) w" r/ i3 t- O" i //Choose I3+ y5 u) D$ H3 W2 K j
S1 = 1;S0 = 1;/ D' @: j: |6 C L/ t, h9 z7 I6 P9 {
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
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+ ?; @( z' _1 t7 N2 o9 i" c end' s( {$ i1 j/ Q3 }2 L
0 Z4 S% p9 @7 @) ^) v9 z6 N1 o% Tendmodule |
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