LIBRARY ieee;
USE ieee.std_logic_1164.all;
USE ieee.std_logic_arith.all;

ENTITY extension IS
PORT (	
		arm_data : inout std_logic_vector(7 downto 0);
		cpu_addr : in 	 std_logic_vector(15 downto 0);
		cpu_read : in 	 std_logic;
		cpu_writ : in 	 std_logic;
		cpu_cs	 : in	 std_logic;
		cpld_rst : in 	 std_logic;
		key_in 	 : in 	 std_logic_vector(7 downto 0);
		key_led	 : out 	 std_logic;
		lcd_light: out 	 std_logic;
		lcd_e 	 : out   std_logic;
		lcd_rw 	 : out   std_logic;
		lcd_rs 	 : out   std_logic;
		lcd_db 	 : out   std_logic_vector(3 downto 0)
);
END extension;

ARCHITECTURE maxpld OF extension IS
	signal lcd_temp	:	std_logic;					
BEGIN
	arm_data <= key_in when cpu_addr="0001000000000001" and cpu_read = '0' and cpu_cs = '0'
				else--鍵碼，地址：0x1001
						"ZZZZZZZZ";
	lcd_light<=lcd_temp;
	process(cpld_rst, cpu_writ)--lcd控制信號lcd_e，地址：0x1002
	begin
		if cpld_rst = '1' then
			lcd_e <= '0';
		elsif cpu_writ'event and cpu_writ = '1' then
			if cpu_addr="0001000000000010" and cpu_cs = '0' then
				lcd_e <= arm_data(0);
			end if;
		end if;
	end process;

	process(cpld_rst, cpu_writ)--lcd控制信號lcd_rw，地址：0x1003
	begin
		if cpld_rst = '1' then
			lcd_rw <= '0';
		elsif cpu_writ'event and cpu_writ = '1' then
			if cpu_addr="0001000000000011" and cpu_cs = '0' then
				lcd_rw <= arm_data(0);
			end if;
		end if;
	end process;

	process(cpld_rst, cpu_writ)--lcd控制信號lcd_rs，地址：0x1004
	begin
		if cpld_rst = '1' then
			lcd_rs <= '0';
		elsif cpu_writ'event and cpu_writ = '1' then
			if cpu_addr="0001000000000100" and cpu_cs = '0' then
				lcd_rs <= arm_data(0);
			end if;
		end if;
	end process;

	process(cpld_rst, cpu_writ)--lcd數據信號，地址：0x1005
	begin
		if cpld_rst = '1' then
			lcd_db(3 downto 0) <= "0000";
		elsif cpu_writ'event and cpu_writ = '1' then
			if cpu_addr="0001000000000101" and cpu_cs = '0' then
				lcd_db(3 downto 0) <= arm_data(7 downto 4);
			end if;
		end if;
	end process;

 	process(cpld_rst, cpu_writ)--lcd背光信號，地址：0x1006
	begin
		if cpld_rst = '1' then
			lcd_temp <= '1';
		elsif cpu_writ'event and cpu_writ = '1' then
			if cpu_addr="0001000000000110" and cpu_cs = '0' then
				lcd_temp <= arm_data(0);
			end if;
		end if;
	end process;
	
	process(cpld_rst, cpu_writ)--key報警燈，地址：0x1007
	begin
		if cpld_rst = '1' then
			key_led <= '0';
		elsif cpu_writ'event and cpu_writ = '1' then
			if cpu_addr="0001000000000111" and cpu_cs = '0' then
				key_led <= arm_data(0);
			end if;
		end if;
	end process;
END maxpld;