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先给出代码+ h# E0 {0 k6 X u
$ u' J2 m$ a5 w' ?module fsm (8 M+ d Y' v7 p
clk,
! j% ?% ]( Z) j4 g( m rst_n,
' g& a; T5 R: M9 G; ~) _$ b w_i,1 B3 `# O! P) `3 C2 U
z_o
6 `6 k9 v$ [, J' Q2 Y& `" |);
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" f1 N4 u9 F; xinput clk;/ k8 @2 f& r# J; _; r) E; K& \
input rst_n;, s7 m3 ` K9 n- i1 c$ a6 Q
input w_i;, k' y% p: h% ?" ^$ X: X" f
output z_o;$ c( j0 D" K/ @- J/ f/ a1 D
$ C: |7 P( e8 G H; n& k+ |parameter IDLE = 2'b00;8 g3 S% @( n- T( a; e4 R
parameter S0 = 2'b01;
& c9 p' j7 k) i' K' q- C( g- E, oparameter S1 = 2'b10;
( h0 q6 P3 F$ N8 m' _. l2 o' o
/ L; o* C6 ^, W" B5 {" [0 i4 x9 D5 [( N4 ireg [1:0] curr_state;
. H5 z7 T ~, W5 `reg [1:0] next_state;3 C* Z* |; G( |5 |' ]
reg z_o; ]& U% G) |( d0 ]: r
" g c- X) I& O4 K$ y% V: l; S// state reg; l( i6 U& {3 ^$ a
always@(posedge clk or negedge rst_n)0 y7 m; L2 ^2 E$ _) {& m/ G/ }
if (~rst_n) curr_state <= IDLE;
: D: t2 _# a `( y5 c7 u8 ^" G else curr_state <= next_state;
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$ m# a# B1 c2 s3 c// next state logic
" _2 A4 O4 `: F# X5 {- f _& |always@(*): j4 U6 |' m- k' i5 e
case (curr_state)
5 L! j# U# z; \! u/ U' p IDLE : if (w_i) next_state = S0;
' `+ }8 H/ a+ [ else next_state = IDLE;
/ I0 p, K8 e$ g# s! V% V* A S0 : if (w_i) next_state = S1;
3 q$ A" c# F0 D3 d1 H else next_state = IDLE;) R. p* x8 G; ?, k! B; J$ D i
S1 : if (w_i) next_state = S1;' y! Z7 e, `5 b/ t
else next_state = IDLE;; p; T) ?. P6 V( X1 H" x1 }
default : next_state = IDLE;
; C% g* t- @2 ] endcase . p* d. |$ j( B1 c- A% }$ B' u+ v w
, l6 \1 i+ a, a. z// output logic& d4 l' V& F: t3 q
always@(*). H5 d$ a8 E" K2 C' r: O' A5 ?
case (curr_state)
1 E& H$ c, ~6 T8 c4 r0 Q IDLE : z_o = 1'b0;7 N% e! f9 ~/ u( ?( L
S0 : z_o = 1'b0;7 B% P$ w7 ^" c- Q- A: w( |
S1 : z_o = 1'b1;
6 `1 Q% g' m, Y7 t default : z_o = 1'b0;+ j/ m) S' N/ Q
endcase
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' L; D. P3 }9 m$ S8 ]7 T pendmodule
$ Y( c, T" [4 [9 E; e6 n- Z1 U+ y& Y- u9 t# C1 F$ r. w! Z
/ V4 b6 n3 F' h" c I R, l7 n! y& V% F2 q5 f6 Z' \1 h, F5 m
然后是状态机的结构图:
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9 [9 C' {# z! k- R$ Y3 @3 p
4 V' ^7 H+ G1 Y/ U2 [2 V9 u. M
1 P9 z- W' m2 T2 d' {; O9 S. z然后再来一个时序图:$ ?" C% d1 S: a/ c& O
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3 g7 {! O7 G+ O9 u1 B
7 v8 ?- @- v6 I( c; C可以发现状态机S0已被综合掉了。- o3 ~2 |# R% |' ^" g( m+ m
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