bcd_bin.vhd

程序主要是用硬件描述语言（VHDL）实现： 4*4键盘扫描

library ieee;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_ARITH.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;

entity BCD_BIN is
    PORT(
          thousand:  IN  integer range 0 to 9;
           hundred:  IN  integer range 0 to 9;
               ten:  IN  integer range 0 to 9;
               one:  IN  integer range 0 to 9;
         data_out :  OUT  STD_LOGIC_VECTOR(9 DOWNTO 0) );
END BCD_BIN  ;

architecture a of BCD_BIN  is