/*
RGB LED Controller
Date: 7-21-05
Author: Evan Dudzik

*This program controls two common-anode RGB LEDs via software-generated PWM.
*The outputs are low for "on" and tri-stated for "off", for directly driving common-anode LEDs.
*The available color values are 0 - 255 (red to yellow to green to blue to purple to red)
*Each LED's color is either solid (chosen with button1 and button2)
	or it is set by whatever character arrives via serial input (using hardware UART)
*There are 4 modes:
	0 = both LEDs serial input color
	1 = LED1 fixed, LED2 serial
	2 = LED1 serial, LED2 fixed
	3 = both LEDs fixed color	
*The mode is chosen by cycling with the mode_button.
*/

#include <system.h>

#pragma DATA 0x2007, 0x3F50//_INTRC_IO & _WDT_OFF & _LVP_OFF

//define important SFR bits for interrupts, UART, and ADC
volatile bit go @ ADCON0.GO;
volatile bit gie @ INTCON.GIE;
volatile bit rcie @ PIE1.RCIE;
volatile bit peie @ INTCON.PEIE;
volatile bit rcif @ PIR1.RCIF;
volatile bit trmt @ TXSTA.TRMT;

//define I/O pins
bit RLED1 @ PORTA.0;
bit GLED1 @ PORTA.1;
bit BLED1 @ PORTA.2;
bit RLED2 @ PORTA.3;
bit GLED2 @ PORTA.4;
bit BLED2 @ PORTB.4;
bit button1 @ PORTB.0;
bit button2 @ PORTB.1;
bit mode_button @ PORTB.3;

char mode;
char r1val, g1val, b1val;
char r2val, g2val, b2val;
char color1, color2, color_in;

void color_decode();

//	interrupt service routine 
void interrupt(void)
{
    if(rcif) //UART Recieve Interrupt
    {
        color_in = rcreg;
        rcreg = 0;
    }
}

//Function: update LED colors with latest received color if needed
inline void checkserial()
{
	if(mode!=3)
	{
		if(mode!=1) //mode 0 or 2 = LED1 serial input
		{	
			if(color1!=color_in)
			{	color1=color_in; 	color_decode();	}
		}
		if(mode<2) //mode 0 or 1 = LED2 serial input
		{
			if(color2!=color_in)
			{	color2=color_in;	color_decode();	}
		}
	}
}

//Function: perform one PWM cycle
//			(all 6 output lines = both LEDs)
void PWM_cycle()
{
	char a;
	RLED1=0; GLED1=0; BLED1=0;
	RLED2=0; GLED2=0; BLED2=0;
	for(a=0; a<255; a++)
	{
		if(a>=r1val)
		{	RLED1 = 1;	}
		if(a>=g1val)
		{	GLED1 = 1;	}
		if(a>=b1val)
		{	BLED1 = 1;	}
		if(a>=r2val)
		{	RLED2 = 1;	}
		if(a>=g2val)
		{	GLED2 = 1;	}
		if(a>=b2val)
		{	BLED2 = 1;	}
		delay_10us(5);
	}
	checkserial();
}
//Function: calculate PWM duty cycles for R, G, and B LED segments
//			based on color1 and color2 values (0-255)
void color_decode()
{
	if(color1<=85)
	{
		r1val = (85 - color1) * 3;
		g1val = color1 * 3;
		b1val = 0;
	}
	else if(color1<=170)
	{
		r1val = 0;
		g1val = (170 - color1) * 3;
		b1val = (color1 - 85) * 3;
	}
	else
	{
		r1val = (color1 - 170) * 3;
		g1val = 0;
		b1val = (255 - color1) * 3;
	}
	if(color2<=85)
	{
		r2val = (85 - color2) * 3;
		g2val = color2 * 3;
		b2val = 0;
	}
	else if(color2<=170)
	{
		r2val = 0;
		g2val = (170 - color2) * 3;
		b2val = (color2 - 85) * 3;
	}
	else
	{
		r2val = (color2 - 170) * 3;
		g2val = 0;
		b2val = (255 - color2) * 3;
	}	
}

//Function: check for button presses and change mode/colors as needed
inline void checkbuttons()
{
	if(!mode_button)
	{
		if(mode==3)
		{ 	mode=0;	}
		else
		{	mode++;	} //cycle modes
		color_decode();
		while(!mode_button){	PWM_cycle();	}
	}
	if(mode!=0)
	{
		if(!button1)
		{
			if(mode!=2) //mode 1 or 3 = LED1 fixed color
			{	color1++; 	color_decode();	}
		}
		if(!button2)
		{
			if(mode!=1) //mode 2 or 3 = LED2 fixed color
			{ 	color2++; 	color_decode();	}
		}
	}
}

void main()
{
	porta   = 00000000b;  
    trisa   = 11100000b; //0 = Output, 1 = Input
	portb   = 00000000b;
    trisb   = 11101111b;    
    osccon  = 01110000b; //internal oscillator @ 8MHz
    ansel   = 00000000b; //all A/D off
    cmcon   = 00000111b; //comparators off    

    // configure USART
    spbrg = 51; 		//9600 baud @ 8MHz
    txsta=00100100b; 	//full duplex asynchronous
    rcsta=10010000b; 	//full duplex asynchronous
    rcie = 1;			//enable RX interrupt
    peie = 1;			//enable peripheral interrupts (needed for RX)
    gie = 1;			//global interrupt enable
    
    //initialize
    color1=0; color2=0; mode = 0;  
	
	//main program loop
	while(1)
	{
		checkbuttons();
		PWM_cycle();
		PWM_cycle();		
		PWM_cycle();
	}
}