--24 Hour Clock Code with seconds and Time setting
--Project "DPF"
--References the  "The Smart Alarm Clock"
--File name: Time_display.vhd

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

entity time_display is
	generic ( num_width : positive :=4;
			  clk_per_sec : natural := 2
		  ); 
	port ( slow_clock : in std_logic;
	       clock      : in std_logic;
	       reset      : in std_logic;
	       am_pm_in   : in std_logic;
	       am_pm_out  : out std_logic;
	       set_clock    : in std_logic;
	       button1, button2: in std_logic;	
	       num1_bcd_out, num2_bcd_out, num3_bcd_out, num4_bcd_out : buffer std_logic_vector ( num_width - 1 downto 0);
	       num1_secs, num2_secs : buffer std_logic_vector ( num_width - 1 downto 0)	
	      );
end time_display;

architecture order of time_display is 


	component button_input_synchronizer1 is
	port( 
			button_in,	-- negative logic input button 
			syn_clock, 	-- system clock to synchronize 
			reset : in std_logic; -- reset
			syn_button_out : buffer std_logic
    		);	
	end component button_input_synchronizer1;

--buttons to set the time
signal synbutton1, synbutton2, slow_clock1:  std_logic;	
	
begin

--instantiates button synchronizer for time setting	
button1_synchronizer: button_input_synchronizer1
	port map(
		 button_in => button1,
		 syn_clock  => clock,
                 reset	=> reset,
                 syn_button_out => synbutton1
		);

button2_synchronizer: button_input_synchronizer1
	port map(
		 button_in  => button2,
		 syn_clock  => clock,
  		 reset	   => reset,
                 syn_button_out => synbutton2
		);
		

		--this process is where the normal clock operation takes place
		--We chose to use compounded if statements so that I would not have a large number of 
		--states,  althouth this is not the method I would normally use I found it to be most appropriate
		--because otherwise if state maps were used there would be 1440 states to deal with and this would be to combersome
		
		show : process(slow_clock,reset)
		variable count : natural := 0;
		variable secs  : natural := 0;

		begin
			if reset = '1' then --resets to a known state 12:00
				num1_bcd_out <= "0000";
				num2_bcd_out <= "0000";
				num3_bcd_out <= "0010";
				num4_bcd_out <= "0001";
				num1_secs <= "0000";
				num2_secs <= "0000";
				am_pm_out <= '0';
				count := 0;	
				secs := 0;
			elsif rising_edge(slow_clock) then	
				if set_clock = '1' then --if setclock is high
					if synbutton1 = '1' then --increment minutes
						num1_bcd_out <= num1_bcd_out + 1;
						if num1_bcd_out = 9 then
							num1_bcd_out <= "0000";
							if num2_bcd_out = 5 then
								num2_bcd_out <= "0000";
							else
								num2_bcd_out <= num2_bcd_out + 1;
							end if;
						end if;
					elsif synbutton2 = '1' then --increments hours
						num3_bcd_out <= num3_bcd_out + '1';
						if num3_bcd_out = 9 then	--sets time to 10:00 when its 9:59
							num3_bcd_out <= "0000";
							num4_bcd_out <= num4_bcd_out + '1';
						elsif num3_bcd_out = 2 and num4_bcd_out =1 then		--resets back to 1 o'clock when it's 12:59
							num3_bcd_out <= "0001";
							num4_bcd_out <= "0000";
						else 
							num3_bcd_out <= num3_bcd_out + '1';
						end if;
						if num4_bcd_out = 1 and num3_bcd_out =2 and num2_bcd_out = 0 and num1_bcd_out = 0 then
							if am_pm_in = '0' then
							   am_pm_out <= '1';
							elsif am_pm_in = '1' then
							   am_pm_out <= '0';
							end if;	
						end if;

					end if;
				else	
					secs := secs + 1;
					if secs = clk_per_sec then
						num1_secs <= num1_secs + 1;
						if num1_secs = 9 then
							num1_secs <= "0000";
							if num2_secs = 5 then
								num2_secs <= "0000";
							else
								num2_secs <= num2_secs + 1;
							end if;
						end if;
						secs := 0;
						count:= count + 1;
					end if;

					if count = 6 then
						if num1_bcd_out = 9 then
							num1_bcd_out <= "0000";	--resets minutes back to 0 when minutes are 9
							if num2_bcd_out = 5 then
								num2_bcd_out <= "0000";	--resets minutes back to 0 when minutes are 59
								if num3_bcd_out = 9 then	--sets time to 10:00 when its 9:59
									num3_bcd_out <= "0000";
									num4_bcd_out <= num4_bcd_out + '1';
								elsif num3_bcd_out = 2 and num4_bcd_out =1 then		--resets back to 1 o'clock when it's 12:59
									num3_bcd_out <= "0001";
									num4_bcd_out <= "0000";
								else 
									num3_bcd_out <= num3_bcd_out + '1';
								end if;
							else
								num2_bcd_out <= num2_bcd_out + '1';
							end if;
						else
							num1_bcd_out <= num1_bcd_out + '1';
						end if;
						if num4_bcd_out = 1 and num3_bcd_out =2 and num2_bcd_out = 0 and num1_bcd_out = 0 then
							if am_pm_in = '0' then
									am_pm_out <= '1';
							elsif am_pm_in = '1' then
									am_pm_out <= '0';
							end if;	
						end if;
						count := 0;
					end if;
				end if;
			end if;
		end process show;
end order;