vb48.vhd

出租车的计费系统

library ieee;
use ieee.std_logic_1164.all;
entity vb48 is
      port(a      :in std_logic_vector(3 downto 0);
           bin          :in std_logic;
           y            :out std_logic_vector(6 downto 0));
end vb48;
architecture vb48_x of vb48 is
        signal dizhi:std_logic_vector(3 downto 0);
begin
        --dizhi<=d&c&b&a;
        process(dizhi,bin)
        begin
           if(bin='0') then
           case a is
                when "0000" =>y<="1111110";
                when "0001" =>y<="0110000";
                when "0010" =>y<="1101101";
                when "0011" =>y<="1111001";
                when "0100" =>y<="0110011";
                when "0101" =>y<="1011011";
                when "0110" =>y<="0011111";
                when "0111" =>y<="1110000";
                when "1000" =>y<="1111111";
                when "1001" =>y<="1110011";
                when others =>y<="0000000";
          end case;
       else
           y<="0000000";
       end if;
      end process;
end vb48_x;