//====================== Simple RGB sensor : main.c ========================
// MELEARD Etienne
// Year 2012
// ATMega8L @ 8MHz (internal RC oscillator)
//==========================================================================



//============================== WARNING ==================================//
//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!//
//                                                                         //
// Fuses must be like -U lfuse:w:0xc4:m -U hfuse:w:0xd1:m                  //
//                                                                         //
//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!//
//=========================================================================//



// ========================================= //
// ==         INCLUDES & MACROS           == //
// ========================================= //

#include <avr/io.h>
#include <sup_avr/io2.h>
#include <avr/interrupt.h>
#include <util/delay.h>


#ifndef cbi
	#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
#endif

#ifndef sbi
	#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
#endif


// ========================================= //
// ==             DEFINITIONS             == //
// ========================================= //

// ================= FUSES ================= //

// Run avrdude -c usbasp -p m8 -U lfuse:w:0xc4:m -U hfuse:w:0xd1:m at first (-F may be needed)


// ================ PINOUTS ================ //

#define LED_R	Bit(PORTD).bitX
#define LED_G	Bit(PORTD).bitY
#define LED_B	Bit(PORTD).bitZ

#define OUT_R	Bit(PORTD).bit2	// MUST be continous
#define OUT_G	Bit(PORTD).bit1
#define OUT_B	Bit(PORTD).bit0

#define LDR_CH	ADCX


// =============== CONSTANTS =============== //

#define false 0
#define true 1

#define OFF 0
#define ON 1

#define LDR_SETTIME	100	// ms

#define COLOR_NONE	0
#define COLOR_BLUE	1
#define COLOR_GREEN	2
#define COLOR_CYAN	3
#define COLOR_RED	4
#define COLOR_PURPLE	5
#define COLOR_YELLOW	6
#define COLOR_WHITE	7


// ================= INITS ================= //

void init(void) {
	cli();
	
	// Outputs
	
	// ADC
	ADCSRA = 0x80;	// Manual mode, 64 prescaler (0.1ms/conv)
	ADMUX = LDR_CH;	// Right adjust, external ref, XX channel
	
	sei();
}


// =============== FUNCTIONS =============== //

uint16_t getLevel(void) {
	ADCSRA |= 1<<ADSC;		// Start conversion
	while(ADCSRA & (1<<ADSC));	// Wait for conversion to end
	return ADC;	// °C
}

void setColor(uint8_t c) {
	LED_R = (c & COLOR_RED);
	LED_G = (c & COLOR_GREEN);
	LED_B = (c & COLOR_BLUE);
}

uint16_t getLevelForColor(uint8_t c) {
	setColor(c);
	_delay_ms(LDR_SETTIME);	// Wait for LDR to react
	return getLevel();
}

uint16_t max(uint16_t a, uint16_t b) {
	if(a > b) return a;
	return b;
}


// ============= MAIN FUNCTION ============= //

int16_t main(void) {
	uint8_t color;
	uint16_t red, green, blue, base, trig;
	
	// Set up
	init();
	
	// Startup dance
	setColor(COLOR_RED);
	_delay_ms(250);
	setColor(COLOR_GREEN);
	_delay_ms(250);
	setColor(COLOR_BLUE);
	_delay_ms(250);
	setColor(COLOR_NONE);
	_delay_ms(250);
	
	while(1) {
		// Get no-component legel for compensation
		base = getLevelForColor(COLOR_NONE);
		
		// Get compensated components levels
		red = getLevelForColor(COLOR_RED) - base;
		green = getLevelForColor(COLOR_GREEN) - base;
		blue = getLevelForColor(COLOR_BLUE) - base;
		
		// Level above which component is considered as present
		trig = max(max(red, green), blue) / 2;
		
		// Compute color
		color = COLOR_NONE;
		if(red > trig) color += COLOR_RED;
		if(green > trig) color += COLOR_GREEN;
		if(blue > trig) color += COLOR_BLUE;
		
		// Send value
		PORTN &= 0xMASK;
		PORTN |= color;
	}
 
	return 0;
}