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LIBRARY ieee;
* Z/ r1 D. J, JUSE ieee.std_logic_1164.all;" r5 @! j. ?" N' w
USE ieee.std_logic_unsigned.all;
7 u$ ?/ F! C- a9 A; C9 k! d& YENTITY counter_backwards60_seg2 IS
% c, X' d1 }! s# y' o* V* g PORT(Clrn,Load,Ena,Clk : IN STD_LOGIC;8 d0 X+ G$ F) h' W! S0 Y
Ring : OUT STD_LOGIC;
" Q1 j# q5 T& O+ R Q0,Q1 : OUT STD_LOGIC_VECTOR(3 downto 0)) ; * q$ }3 l2 E. g# x
END counter_backwards60_seg2;
/ j. W7 O$ D: o4 ~! w9 wARCHITECTURE arc OF counter_backwards60_seg2 IS
. {3 I8 A( t, F; v0 x9 i5 S/ m BEGIN1 v8 |2 a' t$ G9 F7 k
PROCESS (Clk), s4 V: J- t) I" l3 T
VARIABLE imper0 :STD_LOGIC_VECTOR(3 downto 0);# W2 M6 B+ s2 J
VARIABLE imper1 :STD_LOGIC_VECTOR(3 downto 0);
; `% ~) ]7 q H BEGIN
+ o9 z6 e! s% H, v IF Clrn='0' THEN imper1 := "0110"; imper0 := "0000";
8 z+ k( ]8 N$ M. t% D; A1 \) C ELSE IF (Clk'event AND Clk='1') THEN 3 F* n, p& W- `3 Q: t
IF Load='0' THEN imper1:="0110"; imper0:="0000"; - H: R3 g/ `7 e
ELSIF Ena='1' THEN
6 M" ~% U0 [# q' X IF (imper0="1001" AND imper1="0101")THEN
. @6 f" G+ N( L7 F; [ imper0 :="1000";
9 f1 \7 A( z4 U( E: T: R8 d- o ELSIF imper0 >"0000" THEN imper0 := imper0-1;
& Z. x8 l2 F e ELSE imper0:="1001";
. t2 @' s, V9 | IF imper1 >"0000" THEN imper1 := imper1-1;
! [7 K* _. ~" i! ^ ELSE imper1:="0101";
\1 s' f1 s% K END IF;& U- r$ K8 x ?4 y" l
END IF; 1 p, ]- v, r& M; S6 Z
END IF;4 W+ a1 P, L' J f3 t" G6 x
END IF;
; M# D1 X# H. h8 n END IF; ' T' ^8 l+ j" v& W. I; \
Q0 <= imper0; Q1 <= imper1; ' e4 j( \( U5 q; b! T1 r+ D
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)); 2 R5 X0 {7 F8 D) c/ G
END PROCESS ;
+ X' Q9 f+ g$ X( t+ R+ V% fEND arc;
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1 ]; o. e7 T3 N( j上面是我的倒數60秒程式
$ M0 m# h5 h/ C小弟不才
2 a3 u* ~5 L* I+ U不知道怎寫停止# b: Z1 d% t; Z# S: c
只要數1次60就好 |
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