/**
* 
* Breathe Light
* MikroC PIC 16F88 Source Code
*
* Copyright (C) 2005 Matsuda Shota
* http://sgssweb.com/
* sgss@mac.com
*
* ------------------------------------------------------------------------
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* 
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
* 
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
* ------------------------------------------------------------------------
*
*/

#define STARTUP 0
#define INCREASE 1
#define DECREASE 2

#define LIGHT_MINIMUM 20
#define LIGHT_MAXIMUM 255


unsigned int senser_cache;
signed int light;

unsigned short threshold;

unsigned short state;
unsigned long timer;


/**
 * main function
 */
void main() {
	unsigned int i;
	signed int speed;
	unsigned short check_count;
	
	/**
	 * initialization
	 */
	 
	// set internal clock
	// 8MHz
	OSCCON.IRCF2=1;
	OSCCON.IRCF1=1;
	OSCCON.IRCF0=1;

	// set analog input port
	// A0(AN0) B6(AN5) B7(AN6)
	ANSEL = 0b01100001;

	// set input port
	// A0, B6, B7
	TRISA = 0b00000001;
	TRISB = 0b11000000;

	// set pwm clock
	// 5MHz
	PWM_Init(5000);

	// set Timer0 interrupt
	// disable PORTB pull-up
	// prescaler is Timer0 module clock
	// prescaler rate is 1/4
	OPTION_REG = 0b10000001;

	// set port
	// all low
	PORTA = 0b00000000;
	PORTB = 0b00000000;

	
	/**
	 * start
	 */

	// enable Timer0 interruption
	//INTCON.TMR0IE = 1;
	//INTCON.GIE = 1;


	// start pwm
	PWM_Start();
	
	
	// initialize senser cache as 0 so that we can recognize it is not cached
	senser_cache = 0;
	// light value is minimum by default
	light = LIGHT_MINIMUM;
	
	// read parameters
	threshold = Adc_Read(5) / 20;
	timer = Adc_Read(6);
	
	// set state startup
	state = STARTUP;
	// indicate startup
	PORTB.F0 = 1;
	check_count = 0;
		
	
	
	while(1) {
		
		// senser is from 0v to 3.7v, that is 0 to 768 in value.
		// so, we have to adjust value from 0 to 255.
		
		// do processes if senser input below around 3.0v
		if(senser_cache == 0) {
			senser_cache = Adc_Read(0);
		}
		speed = Adc_Read(0) - senser_cache;
		senser_cache = Adc_Read(0);
		
		switch(state) {
			
			case STARTUP:
				if(speed < -threshold) {
					check_count = 0;
				}
				else {
					check_count ++;
				}
				break;
			
			case INCREASE:
				// if any change in senser
				if(speed < -threshold) {
					if(light + 10 > 255) {
						light = LIGHT_MAXIMUM;
					}
					else {
						if(light < 50) {
							light += 5;
						}
						else if(light < 100) {
							light += 6;
						}
						else if(light < 200) {
							light += 8;
						}
						else {
							light += 10;
						}
					
						// reset timer for decline mode
						timer = Adc_Read(6);
					}
				}
				break;
				
			case DECREASE:
				// if any change in senser
				if(speed < -threshold) {
					if(light - 20 < LIGHT_MINIMUM) {
						light = LIGHT_MINIMUM;
					}
					else {
						light -= 20;
					}
				}
				break;
		}
		
		// apply to photo coupler
		PWM_Change_Duty(light);
		
		
		
		// state changing
		switch(state) {
			case STARTUP:
				if(check_count > 30) {
					// change state
					state = INCREASE;
					
					// indicate startup ends
					PORTB.F0 = 0;
				}
				break;
				
			case INCREASE:
				// step timer if light value is set (light is above 10)
				if(light > 50) {
					timer --;
				}
				
				if(timer == 0 || light == LIGHT_MAXIMUM) {
					// change state
					state = DECREASE;
					
					// indicate state change
					for(i = 0; i < 3; i++) {
						PORTB.F0 = 1;
						Delay_ms(125);
						PORTB.F0 = 0;
						Delay_ms(125);
					}
					
					// reset cache
					senser_cache = 0;
				}
				break;
				
			case DECREASE:
				if(light == LIGHT_MINIMUM) {
					// reset timer
					timer = Adc_Read(6);
					
					// change state
					state = INCREASE;
					
					// delay for 2sec so that senser becomes stable
					Delay_ms(2000);
					
					// indicate state change
					for(i = 0; i < 3; i++) {
						PORTB.F0 = 1;
						Delay_ms(125);
						PORTB.F0 = 0;
						Delay_ms(125);
					}
					
					// reset cache
					senser_cache = 0;
				}
				break;
		}
			
			
		Delay_ms(100);
	}
}