SolarTracker.vhd

-- FPGA FINAL PROJECT
-- SOLAR TRACKING SYSTEM
-- 12/9/14

-- KRUNAL BHARGAV
-- NABIL MOHAMMAD
-- MICKEY YEUNG

LIBRARY IEEE;

USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_ARITH.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;
USE IEEE.NUMERIC_STD.ALL;

ENTITY Phototest IS
	PORT	(
			KEY: IN STD_LOGIC_VECTOR(3 DOWNTO 0);
			CLOCK_50: IN STD_LOGIC;
			GPIO: INOUT STD_LOGIC_VECTOR(30 DOWNTO 0);
			HEX0, HEX1, HEX2, HEX3, HEX4, HEX5, HEX6, HEX7: OUT STD_LOGIC_VECTOR(0 TO 6);
			LEDR: OUT STD_LOGIC_VECTOR(18 DOWNTO 0);
			LEDG: OUT STD_LOGIC_VECTOR(7 DOWNTO 0));
 			

			
--GPIO LIST:
--2 - SERVO 1 (pulse width)
--3 - SERVO 2			
--11-4 - ADC 1 input photo resistor (bphoto1)
--19-12- ADC 2 input photo resistor
--22-20 ADC 1 - shared
--26 - ADC CLOCK  Driver - shared
--28 ALE - shared
--29 EOC - 1
--30 EOC - 2

END ENTITY;
ARCHITECTURE rtl of Phototest IS
	

	SIGNAL CLK, RESET, DONE: STD_LOGIC; -- SERVO MOTORS ADJUST ON RISING EDGE OF 'DONE'
	SIGNAL EOC1, EOC2: STD_LOGIC; -- END OF CONVERSION SIGNAL INPUT FROM ADC
	
	SIGNAL ADC_DRIVER: INTEGER RANGE 0 TO 78:= 0; -- ADC CLOCK
	SIGNAL counter: INTEGER RANGE 0 TO 1000000:= 0; -- PWM FOR  CLOCK
	SIGNAL SECOND: INTEGER RANGE 0 TO 1000000:= 0; -- STATE CLOCK
	SIGNAL PULSE_WIDTH1: INTEGER RANGE 49999 TO 120001:= 75000; -- PULSE WIDTH FOR SERVO 1
	SIGNAL PULSE_WIDTH2: INTEGER RANGE 49999 TO 120001:= 75000; -- PULSE WIDTH FOR SERVO 1
	
	SIGNAL B_PHOTO_L1, B_PHOTO_R1: STD_LOGIC_VECTOR(7 DOWNTO 0); -- PHOTORESISTOR VALUES IN BINARY
	SIGNAL B_PHOTO_L2, B_PHOTO_R2: STD_LOGIC_VECTOR(7 DOWNTO 0);
	SIGNAL D_PHOTO_L1, D_PHOTO_R1: INTEGER RANGE 0 TO 255; -- PHOTORESISTOR VALUES IN DECIMAL
	SIGNAL D_PHOTO_L2, D_PHOTO_R2: INTEGER RANGE 0 TO 255;
	
	TYPE count_state IS (stop, read_left, read_right, adjust); -- STATE MACHINE 
	SIGNAL present_state, next_state : count_state;
	ATTRIBUTE syn_encoding	: string;
	ATTRIBUTE syn_encoding	OF count_state	: TYPE IS "00 01 10 11";
	
BEGIN


RESET <= KEY(1);
EOC1 <= GPIO(29);
EOC2 <= GPIO(30);

-- PRESENT STATE PROCESS BLOCK
PROCESS(CLK)
	BEGIN
		IF RESET = '0' THEN
			present_state <= stop;
		ELSIF (rising_edge(CLK)) THEN
			present_state <= next_state;
		END IF;
	END PROCESS;

--NEXT STATE PROCESS BLOCK (ADC CONTROLS, AND DATA)	
PROCESS(present_state, EOC1, EOC2, CLOCK_50, B_PHOTO_L1, B_PHOTO_R1, B_PHOTO_L2, B_PHOTO_R2)
BEGIN
	CASE present_state IS
		WHEN stop =>
			DONE <= '0';
			next_state <= read_left;
		
		WHEN read_left =>
			
			GPIO(22 DOWNTO 20) <= "000"; -- SELECT LINE = 0 ON BOTH ADCs
			--READS LEFT PHOTORESISTOR OF BOTH SERVO MOTORS
			IF(EOC1 = '1') THEN
				B_PHOTO_L1(7 DOWNTO 0) <= GPIO(11 DOWNTO 4);
			END IF;
			IF(EOC2 = '1') THEN
				B_PHOTO_L2(7 DOWNTO 0) <= GPIO(19 DOWNTO 12);
			END IF;
			next_state <= read_right;

		WHEN read_right =>
	
			GPIO(22 DOWNTO 20) <= "111"; -- SELECT LINE = 7 ON BOTH ADCs
			--READS RIGHT PHOTORESISTOR OF BOTH SERVO MOTORS
			IF(EOC1 = '1') THEN
				B_PHOTO_R1(7 DOWNTO 0) <= GPIO(11 DOWNTO 4);
			END IF;
			IF(EOC2 = '1') THEN
				B_PHOTO_R2(7 DOWNTO 0) <= GPIO(19 DOWNTO 12);
			END IF;
			next_state <= adjust;
			
		WHEN adjust =>
			--ALLOW SERVO ADJUSTMENT
			DONE <= '1';
			--CONVERT BINARY TO INTEGER (PHOTORESISTOR VALUES)
			D_PHOTO_L1 <= CONV_INTEGER(B_PHOTO_L1(7 DOWNTO 0));
			D_PHOTO_R1 <= CONV_INTEGER(B_PHOTO_R1(7 DOWNTO 0));
			D_PHOTO_L2 <= CONV_INTEGER(B_PHOTO_L2(7 DOWNTO 0));
			D_PHOTO_R2 <= CONV_INTEGER(B_PHOTO_R2(7 DOWNTO 0));
			
			next_state <= stop;	
	END CASE;
END PROCESS;

--ADC DRIVER
PROCESS (ADC_DRIVER, CLOCK_50)
BEGIN
	IF(rising_edge(CLOCK_50)) THEN
		IF(ADC_DRIVER< 39) THEN
			GPIO(26) <= '0';
		ELSE
			GPIO(26) <= '1';
		END IF;
	END IF;
END PROCESS;

-- STATE TIMER
PROCESS (SECOND, CLOCK_50)
BEGIN
	IF(rising_edge(CLOCK_50)) THEN
		IF(SECOND < 500000) THEN
			CLK <= '0';
		ELSE
			CLK <= '1';
		END IF;
	END IF;
END PROCESS;

--50MHz CLOCK ADDER
PROCESS(CLOCK_50) 
	BEGIN
		IF (CLOCK_50 = '1' AND CLOCK_50'EVENT) THEN
			counter <= counter + 1;
			ADC_DRIVER <= ADC_DRIVER + 1;
			SECOND <= SECOND + 1;
		END IF;
END PROCESS;


-- SERVO 1 MOTOR SIGNAL
PROCESS (CLOCK_50,counter, PULSE_WIDTH1)
	BEGIN
	IF(rising_edge(CLOCK_50)) THEN
		IF(counter < PULSE_WIDTH1) THEN
			GPIO(2) <= '1';
		ELSE
			GPIO(2) <= '0';
		END IF;
	END IF;
END PROCESS;

-- SERVO 2 MOTOR SIGNAL
PROCESS (CLOCK_50, counter, PULSE_WIDTH2)
	BEGIN
	IF(rising_edge(CLOCK_50)) THEN
		IF(counter < PULSE_WIDTH2) THEN
			GPIO(3) <= '1';
		ELSE
			GPIO(3) <= '0';
		END IF;
	END IF;
END PROCESS;

-- SERVO 1 FEEDBACK CONTROLS
PROCESS(DONE, PULSE_WIDTH1, D_PHOTO_L1, D_PHOTO_R1)
BEGIN
	IF (rising_edge(DONE)) THEN
		IF(D_PHOTO_L1 > D_PHOTO_R1 + 5) THEN -- plus 30 error
			IF(PULSE_WIDTH1  < 117500) THEN 
				PULSE_WIDTH1 <= PULSE_WIDTH1 + 2500;
			ELSE 
				PULSE_WIDTH1 <= PULSE_WIDTH1;
			END IF;
		ELSIF(D_PHOTO_R1 > D_PHOTO_L1 + 5) THEN -- plus 30 error
			IF(PULSE_WIDTH1  > 52500) THEN 
				PULSE_WIDTH1 <= PULSE_WIDTH1 - 2500;
			ELSE 
				PULSE_WIDTH1 <= PULSE_WIDTH1;
			END IF;
		ELSE 
			PULSE_WIDTH1 <= PULSE_WIDTH1;
		END IF;
	END IF;
END PROCESS;

-- SERVO 2 FEEDBACK CONTROLS
PROCESS(DONE, PULSE_WIDTH2, D_PHOTO_L2, D_PHOTO_R2)
BEGIN
	IF (rising_edge(DONE)) THEN
		IF(D_PHOTO_L2 > D_PHOTO_R2 + 5) THEN -- plus 5 error term
			IF(PULSE_WIDTH2  < 115000) THEN 
				PULSE_WIDTH2 <= PULSE_WIDTH2 + 5000;
			ELSE 
				PULSE_WIDTH2 <= PULSE_WIDTH2;
			END IF;
		ELSIF(D_PHOTO_R2 > D_PHOTO_L2 + 5) THEN -- plus 5 error term
			IF(PULSE_WIDTH2  > 55000) THEN 
				PULSE_WIDTH2 <= PULSE_WIDTH2 - 5000;
			ELSE 
				PULSE_WIDTH2 <= PULSE_WIDTH2;
			END IF;
		ELSE 
			PULSE_WIDTH2 <= PULSE_WIDTH2;
		END IF;
	END IF;
END PROCESS;


-- ALE (ADDRESS LATCH ENABLE) FOR ADC CONTROL 
PROCESS(SECOND)
BEGIN
	IF(rising_edge(CLOCK_50)) THEN
		IF( SECOND < 15) THEN
			GPIO(28) <= '1';
		ELSE
			GPIO(28) <= '0';
		END IF;
	END IF;
END PROCESS;
		
		
END rtl;