-- EE 552 Project
-- Dustin Demontigny
-- March 10, 2003
-- preset_counter.vhd
-- toggles between preset values for user interface

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

use work.smart_eq_pack.all;

entity preset_counter is
	port(clock : in std_logic;
			reset : in std_logic;
			incr  : in std_logic;
			decr  : in std_logic;
			preset_value : out std_logic_vector(bits-1 downto 0));
end preset_counter;

architecture mixed of preset_counter is
	signal hold : std_logic_vector(bits-1 downto 0);
begin
	toggle_presets : process(clock)
-- push button flags
		variable incr_pressed : integer := 0;
		variable decr_pressed : integer := 0;
	begin
		if clock'event and clock = '1' then
-- reset to preset 0 
			if reset = '0' then
				hold <= "0000";
-- if either pushbutton is pressed, set the flag
			elsif incr = '0' then
				incr_pressed := 1;
			elsif decr = '0' then
				decr_pressed := 1;
-- if pushbuttons are not pressed check for flag
-- and increment or decrement preset value accordingly
			elsif incr_pressed = 1 then
				hold <= hold + "0001";
				incr_pressed := 0;
			elsif decr_pressed = 1 then
				hold <= hold - "0001";
				decr_pressed := 0;
			end if;
-- send the hold value to the output every rising clock edge
			preset_value <= hold;
		end if;
	end process;
	
end mixed;