#include <xc.h>
#include <stdio.h>

#include "lcd.h"

#pragma config FOSC = IRC
#pragma config WDTEN = OFF
#pragma config FCMEN = OFF
#pragma config PWRTEN = ON
#pragma config BOREN = ON
#pragma config BORV = 30
#pragma config LVP = OFF
#pragma config MCLRE = OFF
#pragma config HFOFST = ON
#pragma config PLLEN = OFF
//#pragma config CPUDIV = NOCLKDIV

#define DEBUG

#define _XTAL_FREQ 16000000

#define DDS_FSYNC    LATAbits.LATA5  // AD9834 sync
#define DDS_SCLK    LATAbits.LATA4    // AD9834 clock
#define DDS_SDATA    LATCbits.LATC5    // AD9834 data
#define MAX_FREQ    4300000    // max frequency
#define MIN_FREQ    4000000    // min frequency
#define DEF_FREQ    4248000    // default frequency
#define FIX_FREQ    8000000    // IF frequency
#define EEPROM    0x0000    // EEPROM address

unsigned long freq;    // VFO frequency
unsigned long step;    // frequency up down step
unsigned char renc_now, renc_old;    // value of rotary encoder
unsigned char cflag;    // frequency change flag
unsigned char diff;

void delay_ms(unsigned int t) {
    for(; t > 0; t--)    // 16MHz clock
        __delay_ms(1);    // 1ms: 0.001 / ((1 / (16000000 / 4)) * 1000) = 12
}

void eeprom_write_long(unsigned int adr, long data) {
    unsigned char i;

    for(i = 0; i < 4; i++) {
        eeprom_write(EEPROM + adr * 4 + i, (unsigned char)((data >> (i * 8)) & 0x000000ff));
    }
}

long eeprom_read_long(unsigned int adr) {
    long d;

    d = (unsigned long)eeprom_read(EEPROM + adr * 4);
    d |= (unsigned long)eeprom_read(EEPROM + adr * 4 + 1) << 8;
    d |= (unsigned long)eeprom_read(EEPROM + adr * 4 + 2) << 16;
    d |= (unsigned long)eeprom_read(EEPROM + adr * 4 + 3) << 24;

    return d;
}

/***************************************************************
    serial data send (MSB first)
***************************************************************/
void dds_dataset(unsigned long data, unsigned int bt) {
    unsigned int i;

    DDS_FSYNC = 0;

    for(i = bt; i > 0 ; i--) {
        DDS_SDATA = (data >> (i - 1)) & 0x00000001;
        DDS_SCLK = 0;
        DDS_SCLK = 1;
    }
    DDS_FSYNC = 1;
}

/***************************************************************
    AD9833 DDS control (frequency to serial code)
***************************************************************/
void freq2serial(unsigned long f) {
    unsigned long msb, lsb;
    unsigned long data;
    char buf[10];

    data = (double)(f / 0.093132257);
    msb = (data >> 14) + 0x4000;
    lsb = (data & 0x00003fff) + 0x4000;

    dds_dataset(0x2000, 16);
    dds_dataset(lsb, 16);
    dds_dataset(msb, 16);
}

/***************************************************************
    pin change interrupt  for rotary encoder 
***************************************************************/
void interrupt isr(void) {
    if(INTCONbits.RABIF) {
        if(PORTBbits.RB6 == 1) {
            if(PORTBbits.RB7 == 0)
                renc_now = 0;
            else
                renc_now = 1;
        } else {
            if(PORTBbits.RB7 == 1)
                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;

        INTCONbits.RABIF = 0;
    }
    cflag = 1;
}

/***************************************************************
    lcd write routine
***************************************************************/
void lcd_update() {
    char buf[10];
    
    lcd_gotopos(0, 0);
    sprintf(buf, "%6ld00", freq / 10);
    lcd_puts(buf);
    lcd_gotopos(0, 1);
    sprintf(buf, "step%4d", step * 10);
    lcd_puts(buf);
}

/***************************************************************
    main
***************************************************************/
void main(void) {
    unsigned char sw0_state, sw1_state;
    unsigned int tim0, tim1;
    unsigned long ftmp;

    OSCCON = 0b11110111;    // 16MHz internal clock

    TRISA = 0b00000000;    // RA4,5 AD9834 serial control
    TRISB = 0b11110000;    // RB6,7 rotary encoder input and RB4,5 input
    TRISC = 0b00000000;    // LCD and RC5 AD9834 serial control
    ADCON0bits.ADON = 0;    // ad converter off
    ANSEL = 0;
    ANSELH = 0;
    INTCONbits.RABIE = 1;    // PortA,B pin change interrupt enable
    INTCON2bits.RABPU = 0;    // PortA,B pull-up enable
    INTCON2bits.RABIP = 0;    // PortA,B interruput priority low
    WPUB = 0b11100000;    // RB5,6,7 pull-up
    IOCBbits.IOCB6 = 1;    // RB6 pin change interrupt enable
    IOCBbits.IOCB7 = 1;    // RB7 pin change interrupt enable

    sw0_state = sw1_state = 0;
    freq = DEF_FREQ;
    mode = 0;
    step = 10;
    diff = 0;
    tim0 = tim1 = 0;

    lcd_init();
    lcd_update();

    INTCONbits.GIE = 1;    // general interrupt enable
    cflag = 0;

    delay_ms(500);
    freq2serial(freq);

    while(1) {

        // step down or press for long time to EEPROM memory write
        if(PORTBbits.RB5 == 0) {
            sw0_state = 1;
            delay_ms(10);
            tim0++;
        }
        if(sw0_state && PORTBbits.RB5 == 1) {
            sw0_state = 0;
            tim0 = 0;
            if(mode == 0) {
                   PORTCbits.RC2 = 1;
                mode = 1;
                step = 1000;
                lcd_update();
            } else {
                PORTCbits.RC2 = 0;
                mode = 0;
                step = 10;
                lcd_update();
            }
        }

        // frequency and offset write to EEPROM
        if(tim0 > 100) {
            sw0_state = 0;
            tim0 = 0;
            // write eeprom
            delay_ms(1000);
            lcd_update();
        }

        // frequency changed
        if(cflag) {
            if(diff) {
                if((freq + step) <= MAX_FREQ)
                    freq += step;
            } else {
                if((freq - step) >= MIN_FREQ)
                    freq -= step;
            }
            freq2serial(freq);
            lcd_update();
            cflag = 0;
        }
    }
}