/*
 * si5351a RF two-tone generator 
 *
 * Created: 2022/01/08 20:18:21
 * Author : www.henteko.org
 *
 * 2022/02/13 eeprom_write_dword -> eeprom_write_float
 */ 
#include <avr/io.h>
#include <stdio.h>
#include <util/delay.h>
#include <avr/interrupt.h>
#include <avr/eeprom.h>
#include <avr/pgmspace.h>
#include "TinyI2CMaster.h"
#include "i2c_lcd.h"
#include "si5351a.h"

#define MAX_FREQ	148999999	// max frequency
#define MIN_FREQ	1000000		// min frequency
#define DEF_FREQ	7000000		// default frequency
#define DIF_FREQ	-20000		// default difference frequency
#define MAX_DIFF	1000000		// max difference frequency
#define MIN_DIFF	-1000000	// min difference frequency

FILE *fp;
unsigned char mode;		// operation mode 
long freq;				// frequency
long dfreq;				// difference frequency
long step;				// frequency step
unsigned char pos;		// frequency cursor position
volatile unsigned char cflag;	// rotary-encoder change flag
volatile unsigned char diff;	// frequency up/down flag
volatile unsigned char renc_now, renc_old;	// value of rotary encoder
static unsigned long fmem[2] __attribute__((section(".eeprom")));	// eeprom 

// millisecond order delay
void delay_ms(unsigned int t) {	while(t--)  _delay_ms(1); }

// pin change interrupt for rotaly encoder
ISR(PCINT0_vect)
{
	if(bit_is_set(PINB, PB3)) {
		if(bit_is_clear(PINB, PB4))
			renc_now = 0;
		else
			renc_now = 1;
	} else {
		if(bit_is_set(PINB, PB4))
			renc_now = 2;
		else
			renc_now = 3;
	}

	if((renc_now + 3 - 1) % 3 == renc_old) {
		diff = 0;
	}
	if((renc_now + 3 + 1) % 3 == renc_old) {
		diff = 1;
	}
	renc_old = renc_now;
	cflag = 1;
}

// lcd output frequency
void lcd_output(long f)
{
	unsigned char buf[16];
	unsigned int i; 
	
	if(mode == 0) {
		sprintf(buf, "Fr %9ldHz", f);
		i2c_lcd_goto(0, 0);
	} else {
		sprintf(buf, "Df %9ldHz", f);
		i2c_lcd_goto(1, 0);
	}
	
	for(i = 0; i < 16; i++) {
		i2c_lcd_putch(buf[i]);
		if(i == 5) {
			if(f >= 1000000 || f <= -1000000)
				i2c_lcd_putch('.');
			else
				i2c_lcd_putch(' ');
		}
		if(i == 8) {
			if(f >= 1000 || f <= -1000)
				i2c_lcd_putch('.');
			else
				i2c_lcd_putch(' ');
		}
	}
	if(mode == 0)
		i2c_lcd_goto(0, pos);
	else
		i2c_lcd_goto(1, pos);
}

// write value to eeprom
void setvalue_write(void)
{
	eeprom_busy_wait();
	eeprom_write_float(&fmem[0], dfreq);
	delay_ms(100);
	eeprom_busy_wait();
	eeprom_write_float(&fmem[1], freq);
	delay_ms(100);
}

// read value from eeprom
void setvalue_read(void)
{
	eeprom_busy_wait();
	dfreq = eeprom_read_float(&fmem[0]);
	if(dfreq >= MAX_DIFF || dfreq < MIN_DIFF)
		dfreq = DIF_FREQ;
	eeprom_busy_wait();
	freq = eeprom_read_float(&fmem[1]);
	if((freq + dfreq)> MAX_FREQ || (freq + dfreq) < MIN_FREQ)
		freq = DEF_FREQ;
}

int main(void)
{
	unsigned char sw0_state;
	unsigned int tim0;
	
	DDRB = _BV(PB0)|_BV(PB2);			// PB0,2 output for i2c
	PORTB = _BV(PB3)|_BV(PB4)|_BV(PB1);	// PB1,3,4 pull up(PB1 switch. PB3,4 rotary encoder)

	GIMSK = _BV(PCIE);					// pin change interrupt enable
	PCMSK = _BV(PCINT3)|_BV(PCINT4);	// PB3,4 pin change interrupt

	setvalue_read();
		
	TinyI2C_Master_init();
	si5351_init();
	i2c_lcd_init(32);

	fp = fdevopen(i2c_lcd_putch, NULL);

	step = 1000000;
	pos = 5;
	cflag = diff = sw0_state = tim0 = 0;

	si5351_setfreq(0, freq);
	si5351_setfreq(1, freq + dfreq);
	mode = 0;
	lcd_output(freq);
	mode = 1;
	lcd_output(dfreq);
	mode = 0;
	i2c_lcd_goto(0, pos);
	i2c_lcd_cursor(2);
		
	sei();
	
    while(1) {
		if(cflag) {
			if(mode == 0) {
				if(diff) {
					if((freq + step ) <= MAX_FREQ)
						freq += step;
				} else {
					if((freq - step) >= MIN_FREQ)
						freq -= step;
				}
				si5351_setfreq(0, freq);
				si5351_setfreq(1, freq + dfreq);
				lcd_output(freq);
			} else {
				if(diff) {
					if((dfreq + step ) <= MAX_DIFF)
						dfreq += step;
				} else {
					if((dfreq - step) >= MIN_DIFF)
						dfreq -= step;
				}
				lcd_output(dfreq);
			}
			cflag = 0;
		}
		if(bit_is_clear(PINB, PB1)) {	// frequency step change
			sw0_state = 1;
			delay_ms(30);
			tim0++;
		}
		if(sw0_state && bit_is_set(PINB, PB1)) {
			sw0_state = 0;
			tim0 = 0;
			if(step == 1) {
				step = 10;
				pos = 12;
			} else if(step == 10) {
				step = 100;
				pos = 11;
			} else if(step == 100) {
				step = 1000;
				pos = 9;
			} else if(step == 1000) {
				step = 10000;
				pos = 8;
			} else if(step == 10000) {
				step = 100000;
				pos = 7;
			} else if (step == 100000) {
				step = 1000000;
				pos = 5;
			} else if(step == 1000000) {
				step = 1;
				pos = 13;
			}
			if(mode == 0)
				i2c_lcd_goto(0, pos);
			else
				i2c_lcd_goto(1, pos);
		}

		if(tim0 > 40) {
			sw0_state = 0;
			tim0 = 0;
			if(mode == 0) {
				i2c_lcd_goto(0, 0);
				fprintf(fp, "Difference Setup");
				delay_ms(2000);
				mode = 1;
				step = 1000;
				pos = 9;
				lcd_output(dfreq);
			} else {
				mode = 0;
				cli();
				i2c_lcd_goto(0, 0);
				fprintf(fp, "==Write Memory==");
				delay_ms(2000);
				setvalue_write();
				si5351_setfreq(1, freq + dfreq);
				lcd_output(freq);
				sei();
			}
		}
    }
}