COUNTER.vhd

-- Peter Tu

-- Counter used to determine pixel location in image

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.NUMERIC_STD.ALL;

ENTITY COUNTER IS 
	GENERIC (	RES_WIDTH: INTEGER:=320;
					RES_HEIGHT: INTEGER:=240);
					
	PORT (	CLK : IN STD_LOGIC;
				RST : IN STD_LOGIC;
				EN : IN STD_LOGIC;
				X_LOC : OUT INTEGER;
				Y_LOC : OUT INTEGER);	
END COUNTER;

ARCHITECTURE COUNT OF COUNTER IS
BEGIN
	PROCESS(CLK, RST, EN)
	
	VARIABLE W_LOC: INTEGER := 0;
	VARIABLE H_LOC: INTEGER := 0;
	
	BEGIN
		IF (RST = '0') THEN
			W_LOC := -1;
			H_LOC := 0;
			X_LOC <= 0;
			Y_LOC <= 0;
		ELSIF (RISING_EDGE(CLK)) THEN
			IF (EN = '1') THEN
				W_LOC := W_LOC + 1;
				IF (W_LOC = RES_WIDTH) THEN
					H_LOC := H_LOC + 1;
					W_LOC := 0;
					IF (H_LOC = RES_HEIGHT) THEN
						H_LOC := 0;
					END IF;
				END IF;
				X_LOC <= W_LOC;
				Y_LOC <= H_LOC; 
			END IF;
		END IF;
	END PROCESS;
END COUNT;