[ATmega328] DS1307 RTC I2C(TWI)통신 2탄

1탄에서는 출력만 했는데

이번 2탄에서는 셋업, 출력 두가지를 모두 했습니다. ^^;;

 

#define F_CPU   16000000    //Clock frequency

#define F_SCL   100000      //100kHz

#include <avr/io.h>

#include <stdio.h>

#include <string.h>

#include <util/twi.h>

#include <util/delay.h>

#include <avr/interrupt.h>

 

#define DS1307_R        0xD1

#define DS1307_W        0xD0

#define DS1307_YEAR     0x06

#define DS1307_MONTH    0x05

#define DS1307_DATE     0x04

#define DS1307_DAY      0x03

#define DS1307_HOUR     0x02

#define DS1307_MIN      0x01

#define DS1307_SEC      0x00

 

 

struct Read_DT{

    unsigned char yr, mh, date, dday, hours, minutes, seconds;

};

 

void i2c_init(void) {

    TWSR = 0;

    TWBR = ((F_CPU / F_SCL) - 16) / 2;      //100kHz

    TWCR = 0x04;                            //TWI Enable

}

 

int i2c_start(void) {

    TWCR = (1<<TWINT)|(1<<TWSTA)|(1<<TWEN);         // Send Start Condition

    while((TWCR & (1<<TWINT))==0);                  // Wait for TWINT Flag set

    return 0;

}

 

int i2c_write(unsigned char data) {

    TWDR = data;                                    // Load "data" into TWDR Register. 

    TWCR = (1<<TWINT)|(1<<TWEN);                    // Clear TWINT bit in TWCR to start transmission of address

    while((TWCR & (1<<TWINT)) == 0);                // Wait for TWINT Flag set

    return 0;

}

 

unsigned char i2c_read() {

    TWCR = (1<<TWINT)|(1<<TWEN);

    while((TWCR & (1<<TWINT)) == 0);

    return TWDR;

}

 

int i2c_stop(void) {

    TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWSTO);         // Transmit STOP Condition

    return 0;

}

  

unsigned char i2c_getc(unsigned char cmd) {

    i2c_start();

    i2c_write(DS1307_W);

    i2c_write(cmd);

    i2c_start();

    i2c_write(DS1307_R);

    unsigned char data = i2c_read();

    i2c_stop();

    _delay_us(5);

 

    return data;

}

 

void Tx_Char(char Tdata) {

    while(!(UCSR0A & (1<<UDRE0)));

    UDR0 = Tdata;

}

 

void Tx_String(char *str) {

    while(*str) {

        Tx_Char(*str++);

    }

}

 

Read_DT DS1307_now() {

    Read_DT i;

    i.yr = i2c_getc(DS1307_YEAR);

    i.yr = ((i.yr>>4) & 0x0F)*10 + (i.yr & 0x0F);

    i.mh = i2c_getc(DS1307_MONTH);

    i.mh = ((i.mh>>4) & 0x01)*10 + (i.mh & 0x0F);

    i.date = i2c_getc(DS1307_DATE);

    i.date = ((i.date>>4) & 0x03)*10 + (i.date & 0x0F);

 

    i.dday = i2c_getc(DS1307_DAY);

    i.dday = (i.dday & 0x07);

 

    i.hours = i2c_getc(DS1307_HOUR);

    i.hours = ((i.hours>>4) & 0x07)*10 + (i.hours & 0x0F);

    i.minutes = i2c_getc(DS1307_MIN);

    i.minutes = ((i.minutes>>4) & 0x07)*10 + (i.minutes & 0x0F);

    i.seconds = i2c_getc(DS1307_SEC);

    i.seconds = ((i.seconds>>4) & 0x07)*10 + (i.seconds & 0x0F);

    return i;

}

 

void DS1307_set(byte ss, byte mm, byte hr, byte wd, byte md, byte mh, byte yr) {

    i2c_start();

    i2c_write(DS1307_W);

    i2c_write(0x00);

    i2c_write(DecToBcd(ss));    //seconds

    i2c_write(DecToBcd(mm));    //min

    i2c_write(DecToBcd(hr));    //hour

    i2c_write(DecToBcd(wd));    //weekday

    i2c_write(DecToBcd(md));    //day

    i2c_write(DecToBcd(mh));    //month

    i2c_write(DecToBcd(yr));    //year

    i2c_write(0x00);

    i2c_stop();

    _delay_us(5);

}

 

 

byte DecToBcd(byte val) {

    return ((val/10*16) + (val%10));

}

 

 

int main(void) {

    

    char str[30];

    UCSR0A = 0;

    UCSR0B = (1 << RXCIE0) | (1 << RXEN0) | (1 << TXEN0);    //RX INT EN, RX & TX Enable

    UCSR0C = (1 << UCSZ01) | (1 << UCSZ00);                    //8bit no parity

    UBRR0H = 0;    UBRR0L = 8;     

    

    i2c_init();

//    DS1307_set(50, 2, 17, 3, 17, 7, 18);

    while(1) {

        char *dday;

        Read_DT dt;

        dt = DS1307_now();

        switch(dt.dday) {

            case 0:

                dday = "SUN";

                break;

            case 1:

                dday = "MON";

                break;

            case 2:

                dday = "TUE";

                break;

            case 3:

                dday = "WED";

                break;

            case 4:

                dday = "TUR";

                break;                                                                

            case 5:

                dday = "FRI";

                break;

            case 6:

                dday = "SAT";

                break;                

        }

        sprintf(str, "%02d-%02d-%02d  %02d:%02d:%02d   %s\r\n", dt.yr+2000, dt.mh, dt.date, dt.hours, dt.minutes, dt.seconds, dday);

        Tx_String(str);

        _delay_ms(500);

    }

}

조금 비교를 하자면

구조체를 이용해서 RTC 데이터를 묶어서 이해하기 편하게 했습니다.

그리고 DS1307_now(), DS1307_set(byte..) 함수를 만들었습니다.

DS1307_now함수는 현재시간을 알려주는 함수이고 set함수는 RTC를 셋업하는 함수입니다.

동작을 한번 시켜보면 금방 알수 있을 듯 합니다. ^^

알람시계는 이제 금방 만들수 있지 않을까요?? ㅎㅎ