dispselector_ok.vhd

以CPLD器件EPM7128SLC84-15为核心实现的简易数字频率计

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;

ENTITY dispselector IS
	PORT
	(CLK: IN	STD_LOGIC;
	NUM1: IN	STD_LOGIC_VECTOR(3 DOWNTO 0);
	NUM2: IN	STD_LOGIC_VECTOR(3 DOWNTO 0);
	NUM3: IN	STD_LOGIC_VECTOR(3 DOWNTO 0);
	NUM4: IN	STD_LOGIC_VECTOR(3 DOWNTO 0);
	NUM5: IN	STD_LOGIC_VECTOR(3 DOWNTO 0);
	NUM6: IN	STD_LOGIC_VECTOR(3 DOWNTO 0);
	DIGSGN:out std_logic_vector(0 to 7);
--	DEBUG:out std_logic_vector(3 downto 0);----------debug
	CATSEL:out std_logic_vector(0 to 5)
	);
END dispselector;

ARCHITECTURE arch OF dispselector IS
	SIGNAL DGT : integer range 0 to 9;--要显示的数字
	SIGNAL POS : integer range 0 to 5;--数字出现的位置

	FUNCTION To_Integer(x:STD_LOGIC_VECTOR(3 downto 0)) RETURN integer IS
	BEGIN
		case x is
			when "0000" => return 0;
			when "0001" => return 1;
			when "0010" => return 2;
			when "0011" => return 3;
			when "0100" => return 4;
			when "0101" => return 5;
			when "0110" => return 6;
			when "0111" => return 7;
			when "1000" => return 8;
			when "1001" => return 9;
			when others => return 15;
		end case;
	END To_Integer;

BEGIN

	count6:PROCESS(CLK)
	BEGIN
		if Rising_edge(CLK) then
			if POS>=5 then
				POS<=0;
			else
				POS<=POS+1;
			end if;
		end if;
	END PROCESS count6;

	WITH POS SELECT--阴极控制
		CATSEL<="011111" WHEN 0,
				"101111" WHEN 1,
				"110111" WHEN 2,
				"111011" WHEN 3,
				"111101" WHEN 4,
				"111110" WHEN 5;

	WITH POS SELECT--选择要显示的数位
		DGT<=To_Integer(NUM1) WHEN 0,
			To_Integer(NUM2) WHEN 1,
			To_Integer(NUM3) WHEN 2,
			To_Integer(NUM4) WHEN 3,
			To_Integer(NUM5) WHEN 4,
			To_Integer(NUM6) WHEN 5;

	with DGT select--七段显示信号
		DIGSGN<="11111100" when 0,
				"01100000" when 1,
				"11011010" when 2,
				"11110010" when 3,
				"01100110" when 4,
				"10110110" when 5,
				"10111110" when 6,
				"11100000" when 7,
				"11111110" when 8,
				"11110110" when 9,
				"00000000" when others;

--	with DGT select----------------------debug
--		DEBUG<="0000" when 0,
--				"0001" when 1,
--				"0010" when 2,
--				"0011" when 3,
--				"0100" when 4,
--				"0101" when 5,
--				"0110" when 6,
--				"0111" when 7,
--				"1000" when 8,
--				"1001" when 9,
--				"1111" when others;

END arch;