led七段译码.vhd

含有各类寄存器

--     BCDtoSevenSegment Decoder
--     The use of the std_logic literal '-' (don't care) is primarily for the synthesis tool. This example illustrates the use of the selected signal assignment.
       LIBRARY ieee;
       USE ieee.std_logic_1164.ALL;
       ENTITY seg7dec IS
       PORT(bcdin : IN std_logic_vector(3 DOWNTO 0);
       segout : OUT std_logic_vector(6 DOWNTO 0));
       END seg7dec;
       ARCHITECTURE ver3 OF seg7dec IS
       BEGIN
       WITH bcdin SELECT
       segout <= "1000000" WHEN X"0",
       "1100111" WHEN X"1",
       "1101101" WHEN X"2",
       "0000011" WHEN X"3",
       "0100101" WHEN X"4",
       "0001001" WHEN X"5",
       "0001000" WHEN X"6",
       "1100011" WHEN X"7",
       "0000000" WHEN X"8",
       "0000001" WHEN X"9",
       "-------" WHEN OTHERS;
       END ver3;