#define F_CPU 1000000UL

#include <avr/io.h> //standard include for ATMega16
#include <stdio.h>
#include <avr/interrupt.h>
#include <avr/eeprom.h>
#include <util/delay.h>

#define sbi(x,y) x |= _BV(y) //set bit - using bitwise OR operator 
#define cbi(x,y) x &= ~(_BV(y)) //clear bit - using bitwise AND operator
#define tbi(x,y) x ^= _BV(y) //toggle bit - using bitwise XOR operator
#define is_high(x,y) (x & _BV(y) == _BV(y)) //check if the y'th bit of register 'x' is high ... test if its AND with 1 is 1

#define	F_OSC	100000000.0

#define HOME 	0x02

// input pins
#define	BAND2	PD7
#define	BAND1	PD6
#define	BAND0	PD5
#define MODE	PD4
#define ROTINT	PD3
#define	ROT		PD2
#define STEP	PD1
#define CWSW	PD0

// LCD pins
#define	LCD_D7	PB7
#define	LCD_D6	PB6
#define	LCD_D5	PB5
#define	LCD_D4	PB4
#define	LCD_RS	PB3
#define	LCD_E	PB2

// AD9850 pins
#define D7		PB7
#define	W_CLK	PB1
#define	FQ_UP	PB0

void initInterrupts(void);
void startTimer();
void updateDDS();
void display();
void hex2bcd();
void lcdString(char *s);
void initLcd();
void lcdCmd(char c);
void lcdData(char c);
void setBandMode();

int test = 0;
int timeout = 0;

int enc = 0;
long int freqlow[6] =  {3500000,7000000,10100000,14000000,21000000,28000000,};
long int freqhigh[6] = {3800000,7200000,10150000,14350000,21450000,29700000,};
char str[16];

// Interrupt service routine INT1
ISR(INT1_vect)
{
	// read PD5
	if (PIND & _BV(ROT))
 		enc++;
	else 
		enc--;
}

// Interrupt service routine Timer1
ISR(TIMER1_OVF_vect) 
{ 
	timeout = 1;

//	tbi(PORTB, PB7);			// toggle PB7 for test
} 

void startTimer()
{
	TCNT1 = 65536-1953;			// 2 sec period 
	timeout = 0;
}

void initInterrupts(void)
{
	// PD3 (INT1) and PD5 input
	// DDRD = 0x00;

	// Enable the pull-up resistors
	// PORTD |= (1<<ROTINT)|(1<<ROT);

	// Falling edge in INT1 (PD3 / pin17) to cause interrupt
	MCUCR |= (1<<ISC11);

	// Enable and INT1
	GICR |= (1<<INT1);

	// Setup Timer 1
	TCCR1A = 0x00;			// Normal Mode 
	TCCR1B = 0x05;			// div1024 Prescaler 
	TCNT1 = 65536-1953;		// 2 sec period 

	// Enable interrupts as needed 
	TIMSK |= 0x04;      	// Timer 1 overflow interrupt 

	// enable interrupts
	sei();
}

/*
 * send freq to DDS
 */
void updateDDS(long int f)
{
	long int dds;
	int i;

	dds = ( (double)f * 4294967296.0)/F_OSC;

	// output frequency word
	for (i=0; i<32; i++) {
		cbi(PORTB,D7);
		if (dds & 0x1) {
			sbi(PORTB,D7);
		}
		sbi(PORTB, W_CLK);
		_delay_us(2);
		cbi(PORTB, W_CLK);
		dds >>= 1;
	}

	// output phase = 0;
	for (i=0; i<8; i++) {
		cbi(PORTB,D7);
		sbi(PORTB, W_CLK);
		_delay_us(2);
		cbi(PORTB, W_CLK);
	}

	sbi(PORTB, FQ_UP);
	_delay_us(2);
	cbi(PORTB, FQ_UP);
}

void hex2bcd(long int f)
{
	long int x = 10000000;
	int i;
	char d;

	for (i=0; i<8; i++) {
		d = 0;
		for (;;) {
			f -= x;
			if (f < 0) break;
			d++;
		}
		str[i] = d + 0x30;
		f += x;
		x = x/10;
	}
}

void display(long int f)
{
	int i, pos, leading = 1;
	char c;

	hex2bcd(f);

	// cursor to pos 0
	pos = 0;
	lcdCmd(0x80 + pos);
	_delay_ms(10);

	for (i=0; i<8; i++) {
		if (pos == 8) {
			lcdCmd(0xc0);
		}
		c = str[i];
		if (i==2 || i==5) {
			lcdData('.');
			pos++;
		}
		if (c == '0' && leading) {
			lcdData(' ');
			pos++;
		}
		else {
			lcdData(c);
			pos++;
			leading = 0;
		}
	}
}

void displayStep(int s) {

	lcdCmd(0xc7);
	_delay_ms(10);

	switch (s) {
		case 10:
			lcdData(0x2d);
			break;
		case 100:
			lcdData(0x3d);
			break;
		case 1000:
			lcdData(0x11);
			break;
	}
	_delay_ms(10);
}

void displayMode(int mode) {

	lcdCmd(0xc3);
	_delay_ms(10);

	if (mode & 0x01)
		lcdString("CW ");
	else if (mode & 0x10)
		lcdString("USB");
	else
		lcdString("LSB");
}

void lcdString(char *s) {
	while (*s) lcdData(*s++);
}

void initLcd()
{
	// 4 bits mode
	lcdCmd(0x20);
	_delay_ms(10);
	
	lcdCmd(0x20);
	_delay_ms(10);
	
	// cursor shift right, text no shift
	lcdCmd(0x14);
	_delay_ms(10);

	// display on, no cursor, no blink
	lcdCmd(0x0c);
	_delay_ms(10);

	// shift mode
	lcdCmd(0x06);
	_delay_ms(10);

	// home
	lcdCmd(0x02);
	_delay_ms(10);

	// clear display
	lcdCmd(0x01);
	_delay_ms(10);
}

void lcdCmd(char c)
{
	char t;

	t = c & 0xf0;
	PORTB = t;
	sbi(PORTB, LCD_E);
	_delay_us(1);
	cbi(PORTB, LCD_E);
	_delay_us(100);

	c <<= 4;
	c &= 0xf0;
	PORTB = c;
	sbi(PORTB, LCD_E);
	_delay_us(1);
	cbi(PORTB, LCD_E);
	_delay_us(100);
}

void lcdData(char c)
{
	char t;

	t = c & 0xf0;	
	t |= (1<<LCD_RS);	
	PORTB = t;
	sbi(PORTB, LCD_E);
	_delay_us(1);
	cbi(PORTB, LCD_E);
	_delay_us(100);

	c <<= 4;
	c &= 0xf0;
	c |= (1<<LCD_RS);	
	PORTB = c;
	sbi(PORTB, LCD_E);
	_delay_us(1);
	cbi(PORTB, LCD_E);
	_delay_us(100);
}

int main()
{
	unsigned long int savedfreq = 0, freq = 0, mf = 0;
	int laststep = 0, step;
	unsigned int tmp, band = -1, mode = -1;

	// PORTB is output, default low
	DDRB = 0xff;
	PORTB = 0;

	// PORTD is input with pullup
	DDRD = 0x00;
	PORTD = 0xff;

	initLcd();

	initInterrupts();

	// sync dds
	updateDDS(1);

	step = 100;
	displayStep(step);

	for (;;) {

		// read mode bits PD4 (usb/lsb) and PD (cw)
		tmp = PIND & 0x11;

		if (tmp != mode) {
			
			mode = tmp;

			if (tmp & 0x01) {
				mf = 9001500;
			}
			else if (tmp & 0x10) {
				mf = 9001500;
			}
			else {
				mf = 8998500;
			}

			displayMode(mode);
			updateDDS(freq + mf);
		}

		// read mode
		tmp = PIND>>BAND0;
		tmp &= 0x07;
		tmp ^= 0x07;

		if (tmp != band) {

			if (band != -1) {

				// save current frequency current band
				eeprom_write_dword((unsigned long int *)(band<<2), freq);
			}

			band = tmp;

			// read last frequency for the new band from eeprom
			freq = eeprom_read_dword((unsigned long int *)(band<<2));

			// within band limits
			if (freq < freqlow[band] || freq > freqhigh[band]) {
				freq = freqlow[band];
			}

			// update freq
			display(freq);
			updateDDS(freq + mf);
		}

		// step switch pressed?
		if ( (PIND & (1<<STEP)) == 0) {
	
			_delay_ms(10);
			while ( (PIND & (1<<STEP)) == 0);

			if (step == 10) {
				laststep = step;
				step = 100;
			}
			else if (step == 1000) {
				laststep = step;
				step = 100;
			}
			else if (laststep == 10)
				step = 1000;
			else
				step = 10;
				
			displayStep(step);
		}

		// save frequency in eeprom after 2 secs inactivity
		if (timeout) {

			if (freq != savedfreq) {
				eeprom_write_dword((unsigned long int *)(band<<2), freq);
				savedfreq = freq;
			}
			timeout = 0;
		}

		// handle encoder pulses
		if (enc != 0) {

			if (enc>0) {
				freq += step;
				enc--;
			}
			if (enc<0) {
				freq -= step;
				enc++;
			}

			display(freq);
			updateDDS(freq + mf);

			startTimer();
		}
	}

	return 0;
}