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Key function
/ ]8 h2 Z- s! d按鍵開關 第一次 on時,開始計時。
* ]! W+ h, F. I$ u" c+ Y) G 第二次 on時,停止計時。
! ]: P7 B+ e2 X 第三次 on時,開始計時。
$ a/ X H. h! T未 synthesis,請自行 debug........
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LIBRARY ieee; " b: ]& G+ U u, H
USE ieee.std_logic_1164.all;
# l# {/ C) t5 {/ PUSE ieee.std_logic_unsigned.all;
' s1 s: w: `4 E9 ~, v# v X& gENTITY KeyFunction IS
3 B# p5 `' ^0 P+ ^8 P- [' ^0 [) ^ PORT(CLK,
7 K8 A$ R- o/ f/ _9 M1 y PB,
- X- J/ Q, p3 d1 T. A, S8 G- p1 _ RSTn : IN STD_LOGIC;; I+ c: n9 M+ }1 u+ S
START_COUNT,9 P) r( V( Y: [* C1 H* B! H
PAUSE6 H: R! `& |- V$ f# w, ^
: OUT STD_LOGIC
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END KeyFunction;( m" U" {4 p3 l% h/ x- t, N4 R
ARCHITECTURE arc OF debounce_v IS0 F% ]2 ~6 T- ^! D8 u7 p0 d
SIGNAL currently_state : STD_LOGIC_VECTOR(2 downto 0);$ q: j0 T# H0 ~ q, F
signal pb_reg,debounce_counting,debounce_end : std_logic;& ^, U7 X! \% q
signal debounce_counter : STD_LOGIC_VECTOR(15 downto 0);
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9 q/ [; F V' D' ~4 J8 S# Pconstant debounce_time : STD_LOGIC_VECTOR(15 downto 0):= "0000000000000000";8 U0 U$ D* L( n. W
BEGIN7 U; u2 W, t9 b; Z
7 j5 t! N6 D0 K" `5 L# L% }--============================================================0 K% g# o" F1 ^7 Q$ C
-- get key push state. ( active high)
, Y8 C6 y+ X- g! F--============================================================* {" n1 g0 |8 x1 T
PROCESS (CLK,RSTn,PB,pb_reg,debounce_counting,debounce_end)$ [1 V7 [; l: j
BEGIN
' P0 x, K8 M. f' f0 x6 e if( RSTn = '0') then
7 k8 T9 [! h* c Q' ], y pb_reg <= 1;
W4 [4 \. P: g a/ ? elsif( CLK 'event and CLK ='1')then
% f# {3 V3 k+ |1 Q if( PB='1' and pb_reg ='0')then
# ^6 }" V0 J/ O) M" o0 P7 C debounce_counting <= '1';
0 E2 y3 A. Q# x elsif( debounce_end = '1')then
. O3 q4 W' k+ L& s0 ? debounce_counting <= '0'; : I9 V) q4 J$ `7 r* K* t+ \9 X% e
else# m+ A3 G+ n/ V( }3 H- } e
debounce_counting <= debounce_counting;+ B+ T* h3 R& ?+ [& o
end if;+ f7 z8 G6 p0 @) z2 S. }' m
pb_reg <= PB; $ |4 A `1 r. d9 r( k8 h; {8 s) p
end if; |
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