-- we use UP2 ( ALTERA ) simulator for this program 
-- THIS PROGRAM IS A BCD TO 7 SEGMENT DECODER .
-- 4 dipswitch have to be down press		   
-- 7 segment LED will light .

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;

ENTITY seven_s IS
  PORT (in4: IN STD_LOGIC_VECTOR (3 DOWNTO 0);
              q7: OUT STD_LOGIC_VECTOR (7 DOWNTO 0) );
END seven_s;

ARCHITECTURE q7 OF seven_s IS
BEGIN
--     hgfedcba  "1"=off  "0"=on  if the number more then 9 then it is FAIL .
q7 <= "11000000" when in4="0000" ELSE
      "11111001" when in4="0001" ELSE                 
      "10100100" when in4="0010" ELSE
      "10110000" when in4="0011" ELSE
      "10011001" when in4="0100" ELSE
      "10010010" when in4="0101" ELSE
      "10000010" when in4="0110" ELSE   
      "11111000" when in4="0111" ELSE
      "10000000" when in4="1000" ELSE
      "10011000" when in4="1001" ELSE              
      "00001110" ;        
END q7;