xiaodou.vhd

出租车计费系统的 实现

Library ieee;
use ieee.std_logic_1164.all;
entity xiaodou is
port (
         clk,a:in std_logic;
         aa  :OUT  STD_LOGIC
                );
end;
architecture behv of xiaodou is
 SIGNAL CO1,o1,o2,q: STD_LOGIC;

   BEGIN
    process(a,clk)
begin
o1<=not(a or o2);
o2<=not(q or o1);
if clk'event and clk='1'
 then q<=o2;
end if;
aa<=q;

END PROCESS;
END ;