#include <avr/io.h>
#include <avr/interrupt.h>

volatile uint8_t msgIndex;
volatile uint8_t timerCounter;
volatile uint8_t counter2;
volatile uint8_t audio;
volatile uint8_t key;
volatile uint8_t bit;
volatile uint8_t pause;
volatile uint8_t character;
volatile uint8_t speed;
volatile uint16_t callsign;
volatile uint8_t keyDelay;

#define PERIOD 6

#define A		0b11111001,
#define B		0b11101000,
#define C		0b11101010,
#define D		0b11110100,
#define E		0b11111100,
#define F		0b11100010,
#define G		0b11110110,
#define H		0b11100000,
#define I		0b11111000,
#define J		0b11100111,
#define K		0b11110101,
#define L		0b11100100,
#define M		0b11111011,
#define N		0b11111010,
#define O		0b11110111,
#define P		0b11100110,
#define Q		0b11101101,
#define R		0b11110010,
#define S		0b11110000,
#define T		0b11111101,
#define	U		0b11110001,
#define	V		0b11100001,
#define	W		0b11110011,
#define	X		0b11101001,
#define	Y		0b11101011,
#define	Z		0b11101100,
#define _SPC	0b11101111
#define _0		0b11011111,
#define _1		0b11001111,
#define _2		0b11000111,
#define _3		0b11000011,
#define _4		0b11000001,
#define _5		0b11000000,
#define _6		0b11010000,
#define _7		0b11011000,
#define _8		0b11011100,
#define _9		0b11011110,
#define _BRK	0b11010010
#define _KEYUP	0b10000000
#define _KEYDN	0b10100000

#define MSGMAX 9
#define SHORTSTART 0;
int8_t msg[MSGMAX] = { K B _1 K I X _BRK, _2 _SPC };

uint8_t speeds[8] = {1, 2, 10, 30, 60, 100, 150, 200};
uint8_t dit[8] = {150, 150, 150, 150, 150, 150, 150, 150};
//uint8_t speeds[8] = {1, 1, 1, 10, 30, 60, 100, 200};
//uint8_t dit[8] = {150, 36, 30, 150, 150, 150, 150, 150};
// DIT 		SPEED	WPM 
// 150 		1		12wpm
// 150		2		6wpm
// 150		10		QRSS1
// 150		30		QRSS3
// 150		60		QRSS6
// 150		100		QRSS10
// 150		150		QRSS15
// 150		200		QRSS20
// 36		1		50wpm
// 30		1		60wpm

int main(void)
{
	DDRB = 24;

	TCCR0B |= (1<<CS01) | (1<<CS00);	// Prescale by 8
	TIMSK0 |= (1<<TOIE0);
	msgIndex = 0xff;

	sei();

	return 0;
}

SIGNAL(SIG_OVERFLOW0)
{
	audio++;

	if (audio == 1)
	{
		if (key) PORTB |= 0x08;
	}
	else
	{
		PORTB &= ~(0x08);
		audio = 0;
	}

				// 1500Hz here
	timerCounter++;

	if (timerCounter == dit[speed])
	{
				// 10Hz here
		timerCounter = 0;
		callsign++;

		if (keyDelay)
			keyDelay--;
		else
		{
			counter2++;
			if (counter2 >= speeds[speed])
			{
				counter2 = 0;

				if ((character == _KEYDN) || (character == _KEYUP)) 
				{
					key = 0xff;
					bit = 0;
				}
				else
				{
					if (!pause)
					{
						key--;
						if ((!key) && (!bit)) pause = 2;
					}
					else
						pause--;	
				}

				if (key == 0xff)
				{
					if (!bit)
					{
						msgIndex++;
						if (msgIndex == MSGMAX) 
						{
							msgIndex = SHORTSTART;
							if (callsign > 6000)
							{
								msgIndex = 0;
								callsign = 0;
								speed = 0;
							}
							else
							{
								msgIndex = SHORTSTART;
								speed = (PINB & 0x07);
							}
						}

						bit = 7;
									// Get character from message
						character = msg[msgIndex];
									// Look for 0 signifying start of coding bits
						while (character & (1<<bit))
						{
							bit--;
						}
					}
			
					bit--;

					if (character == _SPC)
						key = 0;
					else if (character == _KEYDN) 
						key = 1;
					else if (character == _KEYUP)
						key = 0;
					else
					{
						key = character & (1<<bit);

						if (key) 
							key = 3;
						else
							key = 1;
					}

					if ((character == _KEYDN) || (character == _KEYUP)) keyDelay = 100;
				}

				if (key)
					PORTB |= (0x10);
				else
					PORTB &= ~(0x10);
			}
		}
	}

	TCNT0 = 156;
}