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LIBRARY ieee; % ?) t4 k$ \- [2 `9 @
USE ieee.std_logic_1164.all;8 |' r% w' }5 `2 Z9 w2 y% c/ s: O: |
USE ieee.std_logic_unsigned.all;6 u$ q, c# U2 |* `
ENTITY counter_backwards60_seg2 IS9 N# ?7 f3 [% C4 s7 q/ f
PORT(Clrn,Load,Ena,Clk : IN STD_LOGIC;
' i5 Y" I, T# d" K9 [% Z( E Ring : OUT STD_LOGIC; 7 p1 L$ r, M }" r4 c- ^
Q0,Q1 : OUT STD_LOGIC_VECTOR(3 downto 0)) ; 3 t, B# c5 Q0 L9 p2 X) d
END counter_backwards60_seg2;
. T F6 m, h1 }* {* A. s* t7 M+ |ARCHITECTURE arc OF counter_backwards60_seg2 IS M P$ K7 V7 b/ ?
BEGIN+ T5 o& R o Q
PROCESS (Clk)0 M- T: S5 S0 G1 f4 h. o0 x
VARIABLE imper0 :STD_LOGIC_VECTOR(3 downto 0);9 @5 F3 j. L" M- ?7 i
VARIABLE imper1 :STD_LOGIC_VECTOR(3 downto 0);1 X5 t7 v! X( B' w
BEGIN
* i8 ?# ]! r0 p' w- ^ IF Clrn='0' THEN imper1 := "0110"; imper0 := "0000";
$ B+ A: D$ o/ v$ ^8 m3 C: I ELSE IF (Clk'event AND Clk='1') THEN
, ~6 {$ G# L$ A6 ~. W9 J/ c- d! [ IF Load='0' THEN imper1:="0110"; imper0:="0000";
4 h/ K$ x* \7 f4 c) J. I' a ELSIF Ena='1' THEN9 h# J4 n# g: ^( u, f. g2 q; @- Y+ p7 s
IF (imper0="1001" AND imper1="0101")THEN4 S5 J( R4 J |2 R* T7 [
imper0 :="1000";
8 e9 o7 ?3 Q2 z8 |2 ~* ]- M ELSIF imper0 >"0000" THEN imper0 := imper0-1;+ a" [! Y' w) Z+ p5 C
ELSE imper0:="1001";
W; H. J5 \! x, Y' E( B1 ^ IF imper1 >"0000" THEN imper1 := imper1-1;2 W9 o8 J+ Q$ Z
ELSE imper1:="0101";
& h1 R+ O' C0 r/ l2 X END IF;" B" Z- z, f% t
END IF; 4 T, s+ l% l" n" h. x6 G
END IF;
) f2 A; E& m# i END IF;
: W* V6 a2 g) {+ F' w END IF; - d7 d2 k* X; S. S- ^
Q0 <= imper0; Q1 <= imper1; 7 d3 u* Y$ s+ X
Ring <= not(imper0(0) or imper0(1) or imper0(2) or imper0(3) or imper1(0) or imper1(1) or imper1(2) or imper1(3));
+ w7 |: U: h, E: y1 G END PROCESS ;) l' B. z2 }% A
END arc;
; U2 U0 ?# U9 U/ C0 J( Y& f* U* {2 q
上面是我的倒數60秒程式" X) @) l$ ]4 K
小弟不才: Y. l' D- v& Z0 G/ k& ~
不知道怎寫停止3 }5 M7 H5 i0 H- @: r' T: b
只要數1次60就好 |
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