keyboard.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 ;

LIBRARY altera;
USE altera.maxplus2.ALL;
--
--*********************************************
ENTITY keyboard IS
	PORT (  
		CLK_4M      : IN   STD_LOGIC ;                     --system original clock 4M
		KEY_IN   : IN   STD_LOGIC_VECTOR (2 downto 0) ; --KEY IN button code
       	CLK_SCAN : OUT  STD_LOGIC_VECTOR (3 downto 0) ; --scan sequence
        out_numb : OUT STD_LOGIC_VECTOR(3 downto 0) ;
		out_func :  OUT STD_LOGIC_VECTOR(3 downto 0) ;
		flag_numb : OUT STD_LOGIC ;
		flag_Func : OUT STD_LOGIC ;
		clear     : OUT STD_LOGIC ;
		CLK_DEBOUNCE : OUT STD_LOGIC ;
		CLK_DISPLAY   : OUT STD_LOGIC_VECTOR(1 DOWNTO 0) 	-- ***
		);
END keyboard ;
--
--*********************************************
ARCHITECTURE a OF keyboard IS
	component debouncing
		port(  d_in   : IN STD_LOGIC ;
			   clk    : IN STD_LOGIC ;	
			   d_out  : OUT STD_LOGIC ) ;
	end component ;

	SIGNAL CLK        : STD_LOGIC ;	
	SIGNAL C_KEYBOARD : STD_LOGIC_VECTOR(1 downto 0) ;	
	SIGNAL C_DEBOUNCE : STD_LOGIC ;	
	SIGNAL C_DISPLAY  : STD_LOGIC_VECTOR(1 downto 0) ;	
	SIGNAL C          : STD_LOGIC_VECTOR(2 downto 0) ;
	SIGNAL N ,F      : STD_LOGIC_VECTOR(3 downto 0) ;
	SIGNAL FN ,FF ,RR2    : STD_LOGIC ;
	SIGNAL SEL        : STD_LOGIC_VECTOR (3 downto 0) ;	
BEGIN
--*******************************************
-- CONNECTION 

	OUT_NUMB <= N ;
	OUT_FUNC <= F ;
	FLAG_NUMB <= FN  ;
	FLAG_FUNC <= FF  ;
	CLK_DEBOUNCE <= C_DEBOUNCE ;
	CLK_DISPLAY <= C_DISPLAY ;
	C_DEBOUNCE <= CLK ;
--
--*********************************************
-- scan signal generator 
counter : block
	Signal  Q   : STD_LOGIC_VECTOR(19 DOWNTO 0);           	
 	Signal 	S   : STD_LOGIC_VECTOR(1 DOWNTO 0) ;  --keyboard scan about 15Hz ***
	SIGNAL 	SEL : STD_LOGIC_VECTOR (3 downto 0);  --1110-1101-1011-0111

BEGIN

	PROCESS (Clk_4M)				       
	Begin
		IF CLK_4M'Event AND CLK_4M ='1' then
			Q <= Q+1;
		END IF;
--			C_KEYBOARD <= Q(19 DOWNTO 18) ;	  -- about 15 Hz  61/4=15	
--			C_DEBOUNCE <= Q(14) ;             -- about 125Hz 
--			C_DISPLAY  <= Q(15 DOWNTO 14) ;   -- about 30 Hz  122/4=30 
			C_KEYBOARD <= Q(5 DOWNTO 4) ;	  -- ***00-01-10-11
			CLK <= Q(0) ;
			C_DISPLAY  <= Q(5 DOWNTO 4) ;

	END PROCESS;
									     
			SEL <= 	"1110" WHEN C_KEYBOARD=0 ELSE
					"1101" WHEN C_KEYBOARD=1 ELSE
					"1011" WHEN C_KEYBOARD=2 ELSE
					"0111" WHEN C_KEYBOARD=3 ELSE
					"1111";
	CLK_SCAN <= SEL ;
end block counter ;
--
--*********************************************
--debounuing ckt
debounuing : block
begin
	U1: debouncing PORT MAP (
					d_in => key_in(0) ,
					d_out => C(0) ,
					clk => C_DEBOUNCE
					);
	U2: debouncing PORT MAP (
					d_in => key_in(1) ,
					d_out => C(1)  ,
					clk => C_DEBOUNCE
					 );
	U3: debouncing PORT MAP (
					d_in => key_in(2) ,
					d_out => C(2)  ,
	     			clk => C_DEBOUNCE 
					);
END block debounuing  ;
--
--******************************************************
--key_decoder
key_decoder : block 
	signal Z : std_logic_VECTOR(4 downto 0) ;   --KEY POSITION
	signal r1, r0 : std_logic ;
begin
	PROCESS(clk)
	begin
		Z <= C_KEYBOARD & C ;
		IF CLK'EVENT  AND CLK = '1'  THEN
			case Z is
					when "11101" => N <= "0000" ;--0
					when "00011" => N <= "0001" ;--1
					when "00101" => N <= "0010" ;--2
					when "00110" => N <= "0011" ;--3
					when "01011" => N <= "0100" ;--4
					when "01101" => N <= "0101" ;--5
					when "01110" => N <= "0110" ;--6
					when "10011" => N <= "0111" ;--7
					when "10101" => N <= "1000" ;--8
					when "10110" => N <= "1001" ;--9
					when others  => N <= "1111" ;
			end case ;
		END IF ;
--****************************
		IF CLK'EVENT  AND CLK = '1'  THEN
			case  Z is
					when "11011" => F <= "0100" ;--*_LOCK
					when "11110" => F <= "0001" ;--#_UNLOCK
					when others  => F <= "1000" ;
			end case ;					
		END IF ;
	end process ;
	FN <= NOT ( N(3) AND N(2) AND N(1) AND N(0) ) ;
	FF <= F(2) OR F(0) ;
--To generate clear signal for ACC 
	PROCESS (CLK)
	BEGIN
		IF CLK'EVENT  AND CLK = '1'  THEN
			R1 <= R0 ; R0 <= FF ; 
		END IF ;
		RR2 <= R1 AND NOT R0 ;
		CLEAR <= RR2 ;
	END PROCESS ;



end block key_decoder ;
END a;
--=========================================================