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Key function5 a% l# r- q4 p; [9 F
按鍵開關 第一次 on時,開始計時。9 L5 c6 e9 h' A7 N
第二次 on時,停止計時。
) O- m# Y* P* s) y: z 第三次 on時,開始計時。 U. A3 G: G0 `; }' n0 Y
未 synthesis,請自行 debug........ 1 c' i3 y' X' B* N4 x
4 E1 p3 ~# f2 g8 K6 XLIBRARY ieee; # [* J" V$ T% i1 e3 Q1 p
USE ieee.std_logic_1164.all;
6 ~' L$ C/ e2 z$ W, mUSE ieee.std_logic_unsigned.all;
* |( V- {6 @6 F) O) K/ b: G2 WENTITY KeyFunction IS/ g7 M0 |5 h3 q8 ]- k% J% M* d
PORT(CLK,
9 X1 S4 d8 J2 C) c9 S# _# u* \- C PB,0 D0 L) k0 L, I* Y9 b) U' I
RSTn : IN STD_LOGIC;* u" S- q- x+ K7 [7 z& M' X, o
START_COUNT,
3 G7 c! I. p5 H: g PAUSE
5 U$ D- y: o5 e$ j: |% Z+ x5 P- n : OUT STD_LOGIC % x+ ? ?, _9 F- ]/ Z' }
);8 a& d1 m% Y) e8 P. Y2 E& ^
END KeyFunction;- R9 Z+ ]0 r6 l' z( N
ARCHITECTURE arc OF debounce_v IS7 D9 e% j1 Z7 ?) h0 t: V
SIGNAL currently_state : STD_LOGIC_VECTOR(2 downto 0);
5 [! y( _6 z& F7 o7 u% Z7 j3 Z" Msignal pb_reg,debounce_counting,debounce_end : std_logic;2 D" I: @1 y! K
signal debounce_counter : STD_LOGIC_VECTOR(15 downto 0);3 m. J+ g; Y8 B1 v, {, Q
9 d4 M, F+ j& P) B S# O6 `
constant debounce_time : STD_LOGIC_VECTOR(15 downto 0):= "0000000000000000";
6 ?2 V. }2 v; W/ q6 N/ T3 P5 fBEGIN7 C q$ T# V6 I9 r: D1 a
# r2 K) t7 n) I
--============================================================) B9 G& @* ^" f* Q0 y- e3 r) \
-- get key push state. ( active high)
: e4 A9 |: ~, _7 m& W" I- w--============================================================0 ]3 S/ w0 m5 {' E) }8 u+ z1 i
PROCESS (CLK,RSTn,PB,pb_reg,debounce_counting,debounce_end)- M* w+ W6 S1 r1 ]/ K! c0 F3 Q
BEGIN5 d; h" ]* s# _
if( RSTn = '0') then v/ F8 H6 N2 C& }* b
pb_reg <= 1;2 H8 i' @. `3 k3 [
elsif( CLK 'event and CLK ='1')then1 Q0 }4 I# R* \8 n
if( PB='1' and pb_reg ='0')then6 q I: f# i+ l& j: O9 c8 c
debounce_counting <= '1'; v, I. f2 E( W
elsif( debounce_end = '1')then" M1 h- B( \) d) o
debounce_counting <= '0';
$ O5 X1 m( m1 R else
0 g. H& d1 L x1 ?* J debounce_counting <= debounce_counting;# r; {9 ?+ o' k6 v
end if;
+ h& y" G; X8 k: g. Q1 \/ b pb_reg <= PB;
) A7 V/ X, C0 |1 r9 p& i1 T end if; |
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