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下面贴上源代码!
! X; z# s5 P4 k6 ?& s; C`define UD #18 G& |) k2 p2 _* J V' I3 n8 T
, f; B _( T4 b7 n. G/ n- ]module KEY_TEST
% ]3 o$ [0 e# ]5 f (
" W4 g4 t( V" N( C, s, u //Input ports.
3 q" k; I$ e$ G% k SYSCLK,
9 g7 m5 [4 U, x5 E4 P# ^3 } RST_B, {" S8 @+ ? G
KEY_B,
7 k$ ]1 E$ C# @- m% l" s9 a% z8 a& ]& T7 a8 Z
//Output ports.
4 Q: ?7 b; q3 ~% z5 y% Y LED_B
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//===========================================================================. e( v: i3 p: K8 S$ }7 Z+ A
//Input and output declaration
2 Q$ f e/ g/ l$ K$ f& ?, F//===========================================================================9 ~4 b! s2 z- R1 u8 z# |) }) J' V
v" }! N' s4 p2 ?8 p# m' u3 Z
input SYSCLK; //System clock, 50MHz.) V2 ?7 t, q2 F5 J& Z- p/ s
input RST_B; //Global reset, low active.
. v2 P" l6 {$ Iinput KEY_B; //Key input, low active.8 r* @; C; J, a5 E- i2 [) y: U
3 B2 a; |3 B2 `
output LED_B; //Led output, low active.& M, e& X, y( B' u7 ~8 J1 x
3 M: [4 a- L1 Y0 J; s
//===========================================================================# g" Q; |: V# `& P3 t. ], b! p
//Wire and reg declaration; a* |9 E: u7 F' V: T
//===========================================================================
1 J7 j' |! a7 q
% i3 u! g" C rwire SYSCLK;. h$ T' P' L) Q2 c
wire RST_B;5 w6 D* i& L# J* u+ c
wire KEY_B;
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, q2 @2 R: a2 b @. `9 w& J# \reg LED_B;
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( S2 X4 E8 J+ d7 u//===========================================================================5 c" U" h! J; x \, D$ r N
//Wire and reg in the module
1 E. F1 ^' n& C* f0 a//===========================================================================
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2 H4 ~6 z8 ?# Yreg [19:0] TIME_CNT; //Counter, count press key time.. u; y4 w3 t2 b4 u$ Z) b
reg [1:0] KEY_REG; //Save the input one cycle every 20ms.
. i$ c0 z @8 E* X+ d: Xreg LED_B_N; //Next value of LED_B.8 W$ z% @1 S+ Z4 i n
( U6 I) l& E! h- s5 N$ u% uwire [19:0] TIME_CNT_N; //Next value of TIME_CNT.9 R0 e L) }! ^( }- x0 K
reg [1:0] KEY_REG_N; //Next value of KEY_REG.
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9 ^- [- J# {4 {% x# I//===========================================================================8 F) U+ V0 x' x2 u( q+ Q
//Logic
4 z- ^4 {8 ~. E ^) c/ _0 O# y% y//===========================================================================
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, v/ ^: A1 t% Q1 J6 ?* Y& f3 |1 y//Count the time the key is pressed, free running.
, [& x" _1 t1 X4 J: Malways @ (posedge SYSCLK or negedge RST_B)! N, S' n% e* z6 y
begin
: i, m$ |7 {8 X7 X L# X if(!RST_B)
9 T p0 @1 z, O. X) d% t! ` TIME_CNT <= `UD 20'h0;
# }, `0 D% V- T4 V$ Y8 G0 @2 C else
+ t* t1 y6 p. ~( | TIME_CNT <= `UD TIME_CNT_N;
8 H0 X3 j- k& bend
$ A5 x1 H3 d7 h3 G( O3 T* k+ _3 U' I! c+ [% V
//Count cycle 20ms
6 _) g1 M% {1 Z; i2 O" Hassign TIME_CNT_N = (TIME_CNT == 20'hf4240) ? 20'h0 : TIME_CNT +1'h1;% ^% L3 R8 s1 w5 P' w
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//Save the key value when some key is press.% a* C4 W! l+ ~5 u
always @ (posedge SYSCLK or negedge RST_B)3 P% O: h* {: {4 }
begin
% q3 N2 r2 j2 w& ], L. v. R if(!RST_B)
; T/ l9 L0 b3 R$ K. n KEY_REG <= `UD 2'h3;( [# x" S$ ~+ k0 F
else % G3 P/ y; I8 `& T" I
KEY_REG <= `UD KEY_REG_N;8 y a6 J1 x) x
end
& x2 p3 B8 U7 y6 W- }, e( @6 c
3 ?+ _$ E6 i, E) j% `' ralways @ (*)" o4 w. b. Z. D9 i- `6 W8 Z
begin5 D) t3 g9 T: ?+ A# h; r; u
if(TIME_CNT == 20'h0)6 ~7 r* e F5 l D0 @
KEY_REG_N = {KEY_REG[0] , KEY_B};
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KEY_REG_N = KEY_REG;
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//Output control.
5 ?6 S2 \5 o. }1 ?- Q/ Valways @ (posedge SYSCLK or negedge RST_B)
5 u+ A/ O$ E: v3 g8 Q0 Ybegin
- A" r' T& ?8 o) z6 e if(!RST_B)
" a+ R: p1 Z8 Q$ m$ Z( C; S LED_B <= `UD 1'h1;
7 j4 R5 s( ]; M6 J# e4 V; u- e else$ ]/ j8 w7 R4 E7 v! ?2 g2 O- d+ o
LED_B <= `UD LED_B_N;8 u' z( @- J8 C% i0 O& O& i) _2 `4 W
end/ b% S# j( O! z0 [8 B, F. w
5 B5 M4 ^# l; s" `3 ualways @ (*)
9 [/ G5 e$ I3 ?& g2 Rbegin2 L' Z( L7 [1 `2 z2 O# _7 Z
if((KEY_REG == 2'b01) && (TIME_CNT == 20'hf4240))5 r# d8 m+ y. s8 @
LED_B_N = ~LED_B;* Y/ p! e# @: H8 o
else
, q' v# m% X) e/ o3 Z" y$ w2 g1 W LED_B_N = LED_B;
. _- ?1 z" r2 C) f( O* ?end0 t+ \% u+ Z: s' z
$ f1 X7 ]. m8 `2 R
endmodule( F. T6 ]6 {7 U6 e* G; Z
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