///////////////////////////////////////////////////////////////////////////////
//
// rgb.c
//
// A small ATtiny2313 program to control an RGB LED connected to
// pins 0-2 of PORTB
//
// Switches on pins 0 and 1 of PORTD control the behavior of the LED
// The default behavior is to slowly change colors. Alternate behavior is
// to show a single color which can be selected.
//
///////////////////////////////////////////////////////////////////////////////

#include "rgb.h"

///////////////////////////////////////////////////////////////////////////////

ISR(TIMER0_OVF_vect)	//timer 0 interrupt for the pwm core.
{
	uint8_t temp;

	static uint8_t count;	// PWM count
	static uint8_t out;		// Value to output to Port B

	count++;
	out = 0;

	// Turn pin on or off for each PWM
	for(temp = 0; temp < NUMBER_OF_PWMS; temp++) {
		if(pwms[temp] <= count) {
			 out |= _BV(temp);
		}
	}

	// Output PWMs
  PORTB = out;

	// Reset interrupt timer
	TCNT0 = 255;
}


///////////////////////////////////////////////////////////////////////////////

void initButtons(void) {
	// Set up input buttons
	DDRD = 0b00000000;
	PORTD = 0b00000011;

	pollStatePrev = BUTTONS_CURRENT;
}

///////////////////////////////////////////////////////////////////////////////

void pollButtons(void) {
	pollState = BUTTONS_CURRENT;	// Read the buttons
	pollStatePrev ^= pollState;		// Set bits that have changed to 1

	pressedButtons = pollStatePrev & pollState;		// Set bits that have been pressed to 1
	releasedButtons = pollStatePrev & ~pollState;	// Set bits that have been released to 1

	pollStatePrev = pollState;	//Save the buttons for next time
}

///////////////////////////////////////////////////////////////////////////////

void delay(uint16_t a) {

	uint16_t b;

	// Simple delay loop
	for (b=0; b<a; b++) {
			nop();
	}
}

///////////////////////////////////////////////////////////////////////////////

void setColor(void) {
	pwms[0] = (color & 0b00000001)?0x00:0xff;
	pwms[1] = (color & 0b00000010)?0x00:0xff;
	pwms[2] = (color & 0b00000100)?0x00:0xff;
}

///////////////////////////////////////////////////////////////////////////////

int main(void) {
	// declare variables
	uint8_t temp;
  uint8_t newpwms[NUMBER_OF_PWMS];	// Colors to work towards
	uint8_t done;											// Count the number of PWMs that have reached newpwms. 3 = done

	// Set up data direction register for Port B
	DDRB |= 0b00000111;

	// Set up timer registers
	TCCR0A = 0x00;
	TCCR0B = (0 << WGM02)|(0 << CS02)|(0 << CS01)|(1 << CS00);
	TIMSK |= (1 << TOIE0);

	// Set starting color
	for(temp=0; temp < NUMBER_OF_PWMS; temp++) {
		pwms[temp] = newpwms[temp] = 255;
	}

	// Initialize button registers and variables
	initButtons();

	// Start interrupts
	sei();

	// Main loop
	while(1) {
		// Color change delay. Also button debounce
		delay(speed);

		// if Changing Color mode
		if (mode == 0) {
			// initialize done variable
			done = 0;

			for(temp=0; temp < NUMBER_OF_PWMS; temp++) {
				// If this PWM has reached its new color increment done
				if (pwms[temp] == newpwms[temp]) {
					done++;
				// Move PWM towards its new color
				} else if (pwms[temp] < newpwms[temp]) {
					pwms[temp] += 1;
				} else if (pwms[temp] > newpwms[temp]) {
					pwms[temp] -= 1;
				}
			}

			// If all the PWMs have reached their new colors
			if (done == NUMBER_OF_PWMS) {

				// Pick a random color (other than black)
				// Each pin is either on or off without all pins being off
				done = (rand() % 6) + 1;

				// Set up PWMs for each pin
				for(temp=0; temp < NUMBER_OF_PWMS; temp++) {
						newpwms[temp] = ((done >> temp) & 0x01) * 255;
				}
			}
		}

		// Get the state of the buttons on Port D
		pollButtons();

		// If mode button is pressed, change mode
		if (releasedButtons & BUTTON_MODE) {
			mode ^= 1;
			// If solid color mode, set color
			if (mode) {
				setColor();
			}
		}

		// If change button is pressed
		if (releasedButtons & BUTTON_CHANGE){
			// Change speed that colors change
			if (mode == 0) {
				speed += 0x40;
				if (speed > 0x80) {
					speed = 0;
				}
				// Blink LED to show speed: 1 = Fast, 2 = Med, 3 = Slow
				cli();
				for (temp = (speed >> 6) + 1; temp > 0; temp--) {
					PORTB = 0x00;
					delay(BLINK_RATE);
					PORTB = 0x07;
					delay(BLINK_RATE);
				}
				PORTB = 0x00;
				delay(BLINK_DELAY);
				sei();
			// Or change color of LED
			} else {
				color += 1;
				color &= 0b00000111;
				if (!color) {
					color += 1;
				}
				setColor();
			}
		}
	}
}