/*
 * si5351a_28mhz_vfo.c
 *
 * Created: 6/26/2022 3:29:55 PM
 *  Author: www.henteko.org
 */ 

#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	289990		// max frequency
#define MIN_FREQ	280000		// min frequency
#define DEF_FREQ	283000		// default frequency
#define DIF_FREQ	122880		// IF frequency
#define ADC_ENABLE	(_BV(ADEN)|_BV(ADIF)|0b111)	// ADC macro
#define ADC_START	(ADC_ENABLE|_BV(ADSC))		// ADC macro

FILE *fp;				// file descriptor for LCD
unsigned long freq;		// frequency
unsigned long dfreq;	// difference frequency
unsigned long tmpfreq;	// temp frequency
unsigned 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[1] __attribute__((section(".eeprom")));	// eeprom

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

// adc routine
unsigned int get_adc(unsigned char ch)
{
	ADMUX = ch;
	ADCSRA = ADC_START;
	loop_until_bit_is_set(ADCSRA, ADIF);

	return ADCW;
}

// pin change interrupt for rotaly encoder
ISR(PCINT0_vect)
{
	if(bit_is_set(PINB, PB1)) {
		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(unsigned long f)
{
	unsigned char buf[8];
	unsigned int i;
	
	sprintf(buf, "%6ld", f);
	i2c_lcd_goto(0, 0);

	for(i = 0; i < 7; i++) {
		i2c_lcd_putch(buf[i]);
		if(i == 1 || i == 4) {
			i2c_lcd_putch('.');
		}
	}
	i2c_lcd_goto(0, pos);
}

// write value to eeprom
void setvalue_write(unsigned char ch)
{
	eeprom_busy_wait();
	eeprom_write_float(&fmem[ch], freq);
	delay_ms(100);
}

// read value from eeprom
void setvalue_read(unsigned char ch)
{
	eeprom_busy_wait();
	freq = eeprom_read_float(&fmem[ch]);
	if(freq >= MAX_FREQ || freq < MIN_FREQ)
	freq = DEF_FREQ;
}

int main(void)
{
	unsigned char sw0_state, sw1_state;
	unsigned int tim0, tim1;
	unsigned int adc;
	unsigned int send;
	unsigned char mode;
	unsigned char tmpstep, tmppos;
	
	DDRB = _BV(PB0)|_BV(PB2);			// PB0,2 output for i2c
	PORTB = _BV(PB1)|_BV(PB4);			// PB1,4 pull up(PB1,4 rotary encoder)

	GIMSK = _BV(PCIE);					// pin change interrupt enable
	PCMSK = _BV(PCINT1)|_BV(PCINT4);	// PB1,4 pin change interrupt
	
	ADCSRA = ADC_ENABLE;				// adc enable

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

	fp = fdevopen(i2c_lcd_putch, NULL);

	step = 10;
	pos = 5;
	send = mode = 0;
	cflag = diff = 0;
	sw0_state = sw1_state = tim0 = tim1 = 0;
	dfreq = DIF_FREQ;

	setvalue_read(0);

	si5351_setfreq(0, (freq - dfreq) * 100);
	lcd_output(freq);
	i2c_lcd_goto(1, 0);
	fprintf(fp, "     MHz");
	i2c_lcd_goto(0, pos);
	i2c_lcd_cursor(2);
	
	sei();
	
	while(1) {
		send = get_adc(0);
		if(send < 900) {
			if(dfreq != 0) {
				dfreq = 0;
				si5351_setfreq(0, freq * 100);
				lcd_output(freq);
			}
		} else {
			if(dfreq == 0) {
				dfreq = DIF_FREQ;
				if(mode == 0) {
					si5351_setfreq(0, (freq - dfreq) * 100);
					lcd_output(freq);
				} else {
					si5351_setfreq(0, (tmpfreq - dfreq) * 100);
					lcd_output(tmpfreq);
				}
			}
		}
		
		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 - dfreq) * 100);
				lcd_output(freq);
			} else {
				if(diff) {
					if((tmpfreq + step ) <= MAX_FREQ)
					tmpfreq += step;
					} else {
					if((tmpfreq - step) >= MIN_FREQ)
					tmpfreq -= step;
				}
				si5351_setfreq(0, (tmpfreq - dfreq) * 100);
				lcd_output(tmpfreq);
			} 
			cflag = 0;
		}

		adc = get_adc(3);	// PB3 adc input
		if(adc < 30) {		// sw0 input
			sw0_state = 1;
			tim0++;
			delay_ms(20);
		}
		if(adc > 100 && adc < 900) {	// sw1 input
			sw1_state = 1;
			tim1++;
			delay_ms(20);
		}

		if(sw0_state && adc > 1000) {	// frequency step change
			sw0_state = 0;
			sw1_state = 0;
			tim0 = 0;
			if(mode == 0) {
				if(step == 1) {
					step = 10;
					pos = 5;
				} else if(step == 10) {
					step = 100;
					pos = 4;
				} else if (step == 100) {
					step = 1000;
					pos = 3;
				} else if (step == 1000) {
					step = 1;
					pos = 7;
				}
			}
			i2c_lcd_goto(0, pos);
		}

		if(sw1_state && adc > 1000) {	// RIT mode
			sw0_state = 0;
			sw1_state = 0;
			tim1 = 0;
			if(mode == 0) {
				mode = 1;
				i2c_lcd_goto(1, 0);
				fprintf(fp, "RIT");
				tmpfreq = freq;
				tmpstep = step;
				tmppos = pos;
				step = 1;
				pos = 7;
			} else {
				mode = 0;
				i2c_lcd_goto(1, 0);
				fprintf(fp, "   ");
				step = tmpstep;
				pos = tmppos;
				si5351_setfreq(0, (freq - dfreq) * 100);
				lcd_output(freq);
			}
			i2c_lcd_goto(0, pos);
		}

		if(tim0 > 60) {					// sw0 long push
			sw0_state = 0;
			tim0 = 0;
			i2c_lcd_goto(1, 0);
			fprintf(fp, "WriteMEM");
			delay_ms(2000);
			setvalue_write(0);
			i2c_lcd_goto(1, 0);
			fprintf(fp, "     MHz");
			lcd_output(freq);
		}
	}
}