scan8.vhd

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library IEEE;
   use IEEE.std_logic_1164.all;
   use IEEE.std_logic_arith.all;
   use IEEE.std_logic_unsigned.all;
 
library work;
   use work.my_package.all;

entity SCAN8 is
      Port (RESET : In	STD_LOGIC;
	    CLK_1M : In	STD_LOGIC;	-- 1MHz Clock
	    ID7 : In UNSIGNED (7 downto 0);
	    ID6 : In UNSIGNED (7 downto 0);
	    ID5 : In UNSIGNED (7 downto 0);
	    ID4 : In UNSIGNED (7 downto 0);
	    ID3 : In UNSIGNED (7 downto 0);
	    ID2 : In UNSIGNED (7 downto 0);
	    ID1 : In UNSIGNED (7 downto 0);
	    ID0 : In UNSIGNED (7 downto 0);
	    SCAN_COL : Out STD_LOGIC_VECTOR (7 downto 0);
	    SCAN_ROW : Out STD_LOGIC_VECTOR (7 downto 0);
	    SCAN_DIG : Out STD_LOGIC_VECTOR (2 downto 0);
	    DISP_ID : Out UNSIGNED (7 downto 0));
end SCAN8;

architecture BEHAVIORAL of SCAN8 is
signal SCAN_COUNT : STD_LOGIC_VECTOR(5 downto 0);
signal iSCAN_LINE : STD_LOGIC_VECTOR(7 downto 0);
signal iSCAN_DIGIT : STD_LOGIC_VECTOR(2 downto 0);
signal iSCAN_ROW : UNSIGNED(2 downto 0);
signal iFONT_CODE : STD_LOGIC_VECTOR(7 downto 0);
signal iSCAN_ADDR : UNSIGNED(10 downto 0);
signal iDISP_CODE : RAM_TYPE(7 downto 0); 
signal iDISP_ID : UNSIGNED(7 downto 0);


component CHAR_FONT 
Port (   
		SCAN_ADDR : In	UNSIGNED (10 downto 0);
		FONT_CODE : Out	STD_LOGIC_VECTOR (7 downto 0)
		);
end component;


begin

----------- 8 digit scan module ------------------------

  process(RESET,CLK_1M)
  begin
  	if RESET = '1' then
		iSCAN_LINE <= "10000000";
		SCAN_COUNT <= "111111";  -- Digit Count & Line Count
  	elsif CLK_1M'event and CLK_1M = '1' then
		iSCAN_LINE <= iSCAN_LINE(6 downto 0) & iSCAN_LINE(7); -- rotate left 1 bit
		SCAN_COUNT <= SCAN_COUNT + 1;
  	end if;
  end process;

  iSCAN_ROW <= CONV_UNSIGNED(CONV_INTEGER(SCAN_COUNT(2 downto 0)),3);
  iSCAN_DIGIT <= not SCAN_COUNT(5 downto 3);
  SCAN_DIG    <= iSCAN_DIGIT;

  iDISP_ID <=   ID7 when iSCAN_DIGIT = "111" else
		ID6 when iSCAN_DIGIT = "110" else
		ID5 when iSCAN_DIGIT = "101" else
		ID4 when iSCAN_DIGIT = "100" else
		ID3 when iSCAN_DIGIT = "011" else
		ID2 when iSCAN_DIGIT = "010" else
		ID1 when iSCAN_DIGIT = "001" else
		ID0;
 
  iSCAN_ADDR <= iDISP_ID & iSCAN_ROW;

  DISP_ID <= iDISP_ID;

  SCAN_COL <= iFONT_CODE;
  SCAN_ROW <= iSCAN_LINE;

  FONT_ROM: CHAR_FONT 
  	Port Map (   
		SCAN_ADDR => iSCAN_ADDR,
		FONT_CODE => iFONT_CODE );


end BEHAVIORAL;