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小弟寫了一個mux 4 to 1的verilog code用xilinx + modelsim SE 6.1f
% j0 [" `. C7 E$ _ f跑模擬0 M" m! D- M3 y7 B% U/ o' {
可是跑出了的波形都是high Z跟unknown + n6 X5 e- u l8 q7 S: |
也就是訊號資料檔沒灌進去
! K6 F+ ?9 o2 c6 y( ]) I" H想請問各位大大
5 s7 Q8 R) \; n我該怎麼修改這個錯誤: P7 {% R. {4 V7 C o
$ d! h: @: N! |; O1 F7 Z, R+ W4 |=======================以下是verilog module code======================
2 V$ M% b/ q: z# u3 h% |module mux4_to_1(out, i0, i1, i2, i3, s1, s0);
% W4 t7 D: {/ V5 h( X* k9 t output out;" ?1 d. d7 W$ ]/ Y& V2 G* W0 U& [
input i0, i1, i2, i3;: _1 n$ P7 w3 t0 L
input s1, s0;' e# @+ m7 c$ O& m
//out declared as register
0 B b$ Q8 R+ K reg out;
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//recompute the signal out if any input signal changes." @4 l6 Z y4 l3 Y6 ]+ O
//All input signals theat cause a recomputation of out to occur must go into the always@(...)1 M6 O# R3 R& J
always@(s1 or s0 or i0 or i1 or i2 or i3); e! P& Y9 Z8 N" l
begin* m4 T& o- m! M {( B6 I6 x$ y
case({s1, s0})
* p$ ?4 z8 E) B8 H4 A 2'b00: out=i0;
$ g8 D3 O) D1 Z+ d2 ], \ 2'b01: out=i1;
! B, H0 R, k2 k, _ 2'b10: out=i2;+ [: y% h# n9 k! c
2'b11: out=i3;
7 e8 M n# u- Y$ C: A' r default: out=1'bx;# v, T" D2 d. s" X% _" H+ H! a% Q
endcase% E1 r. p* a5 y% ?8 F1 Y
end1 b. M7 s9 `1 i3 u4 D5 v
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endmodule
" z. d( T0 @* V$ R# F/ f/ A" ?=======================以下是test bench==========================
9 Q+ W% B# I2 @module stimulus;$ [7 a) K8 A; `/ j
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// Inputs ]* C4 Y' {; n2 u
reg I0,I1,I2,I3;
/ R/ t7 _0 i X9 u* O reg S1,S0;
4 f; v6 a' {; y. _) g- ~1 } // Outputs
/ T# r$ b/ X7 l. x wire OUT;, D. i4 h% ]! i* s- W, l! l0 y4 I
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// Instantiate the Unit Under Test (UUT)
5 M: B- p* b8 o* a i9 q0 i mux4_to_1 uut (: Y" h3 L* k5 s% D, S# |/ K
.out(OUT), 3 ]% x2 w [" H9 z* _* Y% ]$ K
.i0(I0), ' G/ E9 j% k) r* J) e
.i1(I1), " d4 ]- X4 p# T2 z& ]5 Y$ N
.i2(I2),
0 L$ M- x% K" r: @ .i3(I3),
# r& ?7 q( B$ m .s1(S1),
; p! e2 w# f1 H" `- o2 Z. b6 h2 H4 R# { .s0(S0)
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' R6 A# v5 w7 N& K initial begin
8 F( A- u3 f" p* _. j( Z" @9 n3 ]' Z // Initialize Inputs" n& ~ z7 k8 ]: D( J
I0 = 1;( n7 C1 @+ t) u6 ^. ?
I1 = 0;
. V: P0 T4 U; b$ D) S. d. m I2 = 1;( O" \, q* B9 H5 C" P1 [. W
I3 = 0; D2 U6 E7 I' c* p. P; E9 E
8 P, ^- E- T+ v9 j/ w #100 $display("I0=%b, I1=%b, I2=%b, I3=%b\n", I0, I1, I2, I3);
3 [. V, I! F- h //Choose IN0
- L* N" B+ ]6 W! d- [6 Q% \7 ^& j% D S1 = 0;S0 = 0;
0 L$ \8 H. O; ?! S- G #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
! X) ]* a8 O' m //Choose I11 |4 T4 i8 L8 v p4 U& D. L
S1 = 0;S0 = 1;
' k! Q. a- l' w9 B #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);
7 t) U) x: L/ e$ E7 J g //Choose I2
_4 u+ K5 j/ A X- E S1 = 1;S0 = 0;
* S4 {! i0 j% M3 @+ b1 C #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);7 G: C4 F8 x: F, F0 \; X
//Choose I36 z: g, G$ ~5 S+ k
S1 = 1;S0 = 1;
5 v( z+ }8 t- x2 U; y4 c" N #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);; A9 x1 O! o7 p O$ [) y) {1 s# P
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end0 Z/ P; @% Y2 ?! u1 c: r
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endmodule |
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