//----------------------------------------------------------------
//  AVR-Direct Digital Synthesiser
//                sine wave generator
//
//                                              2009-01-25 www.henteko.org
//----------------------------------------------------------------
#include <avr/io.h>
#include <util/delay.h>
#include <avr/pgmspace.h>
#include <avr/interrupt.h>
#include <stdio.h>

#include "lcd.h"

#define cbi(addr,bit)     addr &= ~(1<<bit)
#define sbi(addr,bit)     addr |=  (1<<bit)
#define SF         160000     // Sampling Frequency
#define ACCU    65536   // Accumulator

FILE *fp;                    // for LCD
volatile unsigned int freq;    // DDS出力周波数[Hz]
unsigned int delta;        // 増分 
unsigned int phe;            // フェーズ
unsigned int pos;            // 波形配列のポジション
unsigned char diff;            // 周波数の増減量[Hz]
volatile unsigned char renc_now, renc_old; // エンコーダ値

void delay_ms(unsigned int count)
{while(count--) { _delay_ms(1); }}

const uint8_t  sinewave[] PROGMEM = // sine wave 256 values
{
0x80,0x83,0x86,0x89,0x8c,0x8f,0x92,0x95,0x98,0x9c,0x9f,0xa2,0xa5,0xa8,0xab,0xae,
0xb0,0xb3,0xb6,0xb9,0xbc,0xbf,0xc1,0xc4,0xc7,0xc9,0xcc,0xce,0xd1,0xd3,0xd5,0xd8,
0xda,0xdc,0xde,0xe0,0xe2,0xe4,0xe6,0xe8,0xea,0xec,0xed,0xef,0xf0,0xf2,0xf3,0xf5,
0xf6,0xf7,0xf8,0xf9,0xfa,0xfb,0xfc,0xfc,0xfd,0xfe,0xfe,0xff,0xff,0xff,0xff,0xff,
0xff,0xff,0xff,0xff,0xff,0xff,0xfe,0xfe,0xfd,0xfc,0xfc,0xfb,0xfa,0xf9,0xf8,0xf7,
0xf6,0xf5,0xf3,0xf2,0xf0,0xef,0xed,0xec,0xea,0xe8,0xe6,0xe4,0xe2,0xe0,0xde,0xdc,
0xda,0xd8,0xd5,0xd3,0xd1,0xce,0xcc,0xc9,0xc7,0xc4,0xc1,0xbf,0xbc,0xb9,0xb6,0xb3,
0xb0,0xae,0xab,0xa8,0xa5,0xa2,0x9f,0x9c,0x98,0x95,0x92,0x8f,0x8c,0x89,0x86,0x83,
0x80,0x7c,0x79,0x76,0x73,0x70,0x6d,0x6a,0x67,0x63,0x60,0x5d,0x5a,0x57,0x54,0x51,
0x4f,0x4c,0x49,0x46,0x43,0x40,0x3e,0x3b,0x38,0x36,0x33,0x31,0x2e,0x2c,0x2a,0x27,
0x25,0x23,0x21,0x1f,0x1d,0x1b,0x19,0x17,0x15,0x13,0x12,0x10,0x0f,0x0d,0x0c,0x0a,
0x09,0x08,0x07,0x06,0x05,0x04,0x03,0x03,0x02,0x01,0x01,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x01,0x02,0x03,0x03,0x04,0x05,0x06,0x07,0x08,
0x09,0x0a,0x0c,0x0d,0x0f,0x10,0x12,0x13,0x15,0x17,0x19,0x1b,0x1d,0x1f,0x21,0x23,
0x25,0x27,0x2a,0x2c,0x2e,0x31,0x33,0x36,0x38,0x3b,0x3e,0x40,0x43,0x46,0x49,0x4c,
0x4f,0x51,0x54,0x57,0x5a,0x5d,0x60,0x63,0x67,0x6a,0x6d,0x70,0x73,0x76,0x79,0x7c,
};

//----------------------------------------------------------------
// Timer1 Compare match interrupt
//   サンプリング周期で割り込み。波形のポジションを計算して出力。
// ---------------------------------------------------------------
ISR(TIMER1_COMPA_vect)
{
    phe += delta;
    pos = phe >> 8;

    PORTD = pgm_read_byte(&sinewave[pos]);
}

//----------------------------------------------------------------
// Pin changed interrupt
//   ロータリーエンコーダからの信号で割り込み。
//   右回りか左回りかを判別してDDS周波数を増減
//----------------------------------------------------------------
ISR(SIG_PIN_CHANGE1)
{
    if(bit_is_set(PINC, PC4)){
        if(bit_is_clear(PINC, PC5))
            renc_now = 0;
        else 
            renc_now = 1;
    } else {
        if(bit_is_set(PINC, PC5))
            renc_now = 2;
        else
            renc_now = 3;
    }

    if((renc_now + 3 + 1) % 3 == renc_old) {
        if(freq > 4000)
            freq -= diff;
    }
    if((renc_now + 3 - 1) % 3 == renc_old) {
        if(freq < 14000)
            freq += diff;
    }

    renc_old = renc_now; 
    delta = freq * ACCU / SF;
}

int main()
{
    unsigned char sw0_state;

    DDRB = 0b11111111;        // LCD Output
     DDRC = 0b00000001;        // pc1 SW pc4,5 r-enc input pc0 led
    DDRD = 0b11111111;        // DDS Output
    PORTD = 0b00000000;        // 
    PORTC = 0b00000010;        // pull up

    lcd_init();
    lcd_cls();
    fp = fdevopen(lcd_putch, NULL);        // LCD出力ファイルディスクプリタ

    sw0_state = 0;
    PCICR = _BV(PCIE1);
      PCMSK1 = _BV(PCINT12)|_BV(PCINT13);

    TCCR1B = 0b01001001;    // Timer1 プリスケーラ 1/1
    TIMSK1 = _BV(OCIE1A);    // Timer1 compare match A interrupt
    OCR1A = 124;                // 20MHz sampling 200kHz 20000000/160000=125(-1)  
    
    phe = 0;
    diff = 1;                // Frequency Up Down default 1Hz
    freq = 10000;

    delta = freq * ACCU / SF;
    lcd_goto(0, 0);
    fprintf(fp, "%8d", freq);
    lcd_goto(1, 0);
    fprintf(fp, "%8ld", (unsigned long)freq * 1024l);

    sei();

    while(1) {
    
        if(bit_is_clear(PINC, PC1)) {
            sw0_state = 1;            
            delay_ms(10);
        }
        if(sw0_state && bit_is_set(PINC, PC1)) {
            sw0_state = 0;
            if(diff == 1) {
                diff = 10;
                sbi(PORTC, PC0);
            } else {
                diff = 1;
                cbi(PORTC, PC0);
            }
        }

        lcd_goto(0, 0);
        fprintf(fp, "%8d", freq);
        lcd_goto(1, 0);
        fprintf(fp, "%8ld", (unsigned long)freq * 1024l);
    }
}