display.vhd

《VHDL与数字电路设计》配套光盘,可以实际调用

-- ********************************************
LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_ARITH.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;
--
--*********************************************
ENTITY display is
	PORT( 
 		 CLK        : in   STD_LOGIC;                      --system clock
		 C_DISPLAY  : in   STD_LOGIC_VECTOR(1 DOWNTO 0) ;  --CLK for display
         ACC        : in   STD_LOGIC_VECTOR (15 downto 0); --digit data 4 numbers
		 DBOUT      : OUT  STD_LOGIC_VECTOR(3 DOWNTO 0) ;  --showing data 	
		 SEGOUT		: OUT  STD_LOGIC_VECTOR(6 DOWNTO 0);   -- SEG7 Display O/P
	     SELOUT		: OUT  STD_LOGIC_VECTOR(3 DOWNTO 0)   -- Select SEG7 O/P	
		);
END display ;
--
--*********************************************
ARCHITECTURE a OF display IS
	SIGNAL 	DB    	: STD_LOGIC_VECTOR( 3 DOWNTO 0);	-- Number Display Signal	
	SIGNAL  SEG		: STD_LOGIC_VECTOR( 6 DOWNTO 0);	-- SEG7 Display Signal
	SIGNAL  SEL		: STD_LOGIC_VECTOR( 3 DOWNTO 0);	-- Select SEG7 Signal
 	Signal 	S	    : STD_LOGIC_VECTOR(1 DOWNTO 0) ;    -- display scan sequence
BEGIN

Connection : Block
Begin
	SELOUT <= SEL ;					-- Seg7 Disp Selection 
	SEGOUT(6 DOWNTO 0) <= SEG;		-- Seven Segment Display	
	S <= C_DISPLAY ;
	DBOUT <= DB ;
End Block Connection;
--
--**********************************************
--
--**********************************************
MULTIPLEXER : BLOCK
BEGIN
-- to decide which data will send out 		
	DB <= ACC(15 DOWNTO 12) WHEN S = 0 ELSE 
	      ACC(11 DOWNTO  8) WHEN S = 1 ELSE
	      ACC(7  DOWNTO  4) WHEN S = 2 ELSE
	      ACC(3  DOWNTO  0) ;
-- to decide which 7_segment can display 	     
	SEL <= 	"1110" WHEN S=0 ELSE  
			"1101" WHEN S=1 ELSE
			"1011" WHEN S=2 ELSE
			"0111" ;
End Block MULTIPLEXER ;
--**********************************************
--
SEVEN_SEGMENT : Block	-- Binary Code -> Segment 7 Code
Begin
		   --gfedcba
	SEG <= 	"0111111" WHEN DB = 0 ELSE
		 	"0000110" WHEN DB = 1 ELSE
 			"1011011" WHEN DB = 2 ELSE
			"1001111" WHEN DB = 3 ELSE
			"1100110" WHEN DB = 4 ELSE
			"1101101" WHEN DB = 5 ELSE
			"1111101" WHEN DB = 6 ELSE
		 	"0000111" WHEN DB = 7 ELSE
 			"1111111" WHEN DB = 8 ELSE
			"1101111" WHEN DB = 9 ELSE
			"0001000";
End Block SEVEN_SEGMENT;											

END a;