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小弟寫了一個mux 4 to 1的verilog code用xilinx + modelsim SE 6.1f4 L/ k9 \$ D9 ?( j# [4 L& {
跑模擬) T' v+ V0 a8 [7 e. I$ P& a) _4 d
可是跑出了的波形都是high Z跟unknown
5 Z0 R: o: }5 C也就是訊號資料檔沒灌進去
8 [; ?% g$ M* U4 A) `1 b想請問各位大大/ ]. O/ H3 T- ^6 u4 V/ m( P
我該怎麼修改這個錯誤
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; _& |- E. }9 ?* w ]3 [5 f=======================以下是verilog module code======================; E0 K! @2 e) p0 P' ^, q
module mux4_to_1(out, i0, i1, i2, i3, s1, s0);
4 b( d& J; L- O [7 W4 m output out;
0 `" e1 e( h2 f input i0, i1, i2, i3;
8 C0 q2 l- l+ e2 A; ^ s input s1, s0;
8 ~0 z0 H# w% Q$ K, q) R* s& _7 R m //out declared as register" T$ W* s6 r* w! K' J, D
reg out;6 R" W5 s) o$ t# x+ k: }! x
# V- I* q+ M4 J; P( A: H) C. M& a //recompute the signal out if any input signal changes.) H* R( K/ l# I+ c: d% p
//All input signals theat cause a recomputation of out to occur must go into the always@(...)$ I: }4 @; @) ?
always@(s1 or s0 or i0 or i1 or i2 or i3)
- } w a8 ~ S1 f8 ] begin
l2 x, g4 n+ m, Q+ p4 ?. e case({s1, s0})
7 a0 N( X# w ?# Y 2'b00: out=i0;
E; H/ I3 r$ \% \+ N7 j8 J 2'b01: out=i1;
7 g. t; A& s+ O 2'b10: out=i2;
/ T* z2 G3 c$ ?6 D4 w! `, `& x 2'b11: out=i3;: u/ Z& ]+ n- M$ {5 w
default: out=1'bx;
* p% i+ Y0 O' a( J( B o4 z endcase" `! V2 S$ @, V1 ^$ ~; h, c1 W
end/ B8 i" D+ y# ]" g
' e/ |. _3 \) c% J ?8 l. `/ |$ I+ u+ Dendmodule2 S, e& {, k! Z, h( N
=======================以下是test bench==========================2 Z2 f. }. O `$ ~9 I- s. O6 H* _
module stimulus;
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) o2 C% z2 D: v9 h // Inputs
2 k. z9 @, o# w. L, D reg I0,I1,I2,I3;8 D* x: m' N3 l: }& t) M; S
reg S1,S0;- Y! T, ], `: |; w% c0 L
// Outputs8 B0 R$ H" c7 x
wire OUT;$ R$ P) w: `- W0 G1 m
/ _! b! v: k5 r* F // Instantiate the Unit Under Test (UUT)
, V# ~1 v6 c! |7 z mux4_to_1 uut (# T0 y" R& g3 z2 u! X# s: ^
.out(OUT), . I- h* N8 s6 l) M6 m
.i0(I0), 7 O1 h3 }6 V# ^( y n2 C
.i1(I1), 8 o7 x! s/ b& Z
.i2(I2),
; k3 ~) j& m0 y8 T4 P/ J .i3(I3), o% W, o9 S+ v' F
.s1(S1), : p. j# y+ L; n2 F/ a1 t6 s
.s0(S0)( Z9 M0 P0 L- Q! D: w5 i3 L9 E
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initial begin
5 q; K! [& \. n2 r: Z1 C+ s // Initialize Inputs' d" X( K% u& ]$ |) X
I0 = 1;* m1 y3 V1 n1 r% M4 l8 C
I1 = 0;2 i* \2 P% d1 c. }( l- f
I2 = 1;
' E% h$ ~2 H9 [- B( R I3 = 0;) O; V0 ]6 J3 E0 ?+ K; E+ x. T2 c
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#100 $display("I0=%b, I1=%b, I2=%b, I3=%b\n", I0, I1, I2, I3);+ Y. x* y5 r# z5 s& \" R
//Choose IN03 z$ c! s/ N1 R% }
S1 = 0;S0 = 0;
$ S7 L3 F5 k, U' k& r* o/ G0 F #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);- G0 T* u* v+ i$ q" R
//Choose I1
# z. o9 C% r: C, p- Y6 G S1 = 0;S0 = 1;+ ?9 p2 b& X- S2 J3 B, Q& ]: h( I
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);" ~- H& l, j! m2 w/ _6 S
//Choose I2
# o p% t, A# s8 H4 e* {! { S1 = 1;S0 = 0;
# Z4 y$ X/ o" ~+ D( z) g3 K #100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);& V8 d9 [5 v3 ~- }8 o0 {/ ~: I3 a, C
//Choose I3
% d- k: F& N) b+ f" z S1 = 1;S0 = 1;& l" {: D3 V, y3 ^7 ?
#100 $display("S1=%b, S0=%b, OUT=%b\n", S1, S0, OUT);( z2 p b/ k7 P
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end
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endmodule |
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