DS1307.c

#include <avr/io.h>

// #include <util/twi.h>

#include <avr/interrupt.h>

#include "DS1307.h"

void twi_error()

{

  uart_puts("TWI Fehler erkannt\n\r");

}

void twi_init(void)

{

  TWSR = 0x00;

  //TWSR |= (1 << TWPS1) | (1 << TWPS0);  Prescaler=1

  TWBR = 152;        // SCL=50KHz @ 16 MHz

  TWCR |= (1 << TWEN);  //TWI aktivieren

}

void twi_start(void)

{

  TWCR = (1 << TWSTA) | (1 << TWEN) | (1 << TWINT);

  while(!(TWCR & (1 << TWINT)));

  if((TWSR & TW_STATUS) != TW_START)

  {

    uart_puts("Fehler beim Senden der Start-Condition\n\r");

    uart_putc(TWSR);

  }

}

void twi_writeadr(uint8_t adr, uint8_t wr)  //W=0 R= alles außer 0

{

  adr=(DS1307ADR << 1);

  if(wr)

    adr |= 1;    //Beim lesen SLA+R übertragen ansonsten LSB auf 0 lassen (SLA+W)

  TWDR=adr;

  TWCR = (1 << TWEN) | (1 << TWINT);

  while(!(TWCR & (1 << TWINT)));

  if ((adr & 1) && ((TWSR & TW_STATUS) != TW_MR_SLA_ACK))

    uart_puts("Fehler beim Senden der Adresse\n\r");

  if (!(adr & 1) && ((TWSR & TW_STATUS) != TW_MT_SLA_ACK))

    uart_puts("Fehler beim Senden der Adresse\n\r");

}

void twi_writedata(uint8_t data)

{

  TWDR=data;

  TWCR = (1 << TWEN) | (1 << TWINT);

  while(!(TWCR & (1 << TWINT)));

  if((TWSR & TW_STATUS) != TW_MT_DATA_ACK)

    uart_puts("Fehler beim Senden der Daten\n\r");

}

uint8_t twi_readdata(void)

{

  uint8_t data;

  TWCR = (1 << TWEN) | (1 << TWINT);

  while(!(TWCR & (1 << TWINT)));

  data = TWDR;

  return data;

}

void twi_stop(void)

{

  TWCR = (1 << TWEN) | (1 << TWSTO) | (1 << TWINT);

  while(TWCR & (1 << TWSTO))

    ;

}

void ds1307_writereg(uint8_t adr,uint8_t data)

{

  twi_start();

  twi_writeadr(DS1307ADR,TW_WRITE);

  twi_writedata(adr);

  twi_writedata(data);

  twi_stop();

}

uint8_t ds1307_readreg(uint8_t adr)

{

  uint8_t data;

  twi_start();

  twi_writeadr(DS1307ADR,TW_WRITE);

  twi_writedata(adr);

  twi_stop();

  twi_start();

  twi_writeadr(DS1307ADR,TW_READ);

  data=twi_readdata();

  twi_stop();

  return data;

}

void ds1307_gettime(void)

{

  uint8_t seconds,minutes,hours;

  uint8_t day, date, month, year;

  seconds = ds1307_readreg(0);

  minutes = ds1307_readreg(1);

  hours = ds1307_readreg(2);

  day = ds1307_readreg(3);

  date = ds1307_readreg(4);

  month = ds1307_readreg(5);

  year = ds1307_readreg(6);

  day = ds1307_readreg(3);

  date = ds1307_readreg(4);

  month = ds1307_readreg(5);

  year = ds1307_readreg(6);

  seconds &= ~128;

  uart_putc(((hours >> 4) & 0x01) + 0x30);

  uart_putc((hours & 0x0F) + 0x30);

  uart_putc(':');

  uart_putc((minutes >> 4) + 0x30);

  uart_putc((minutes & 0x0F) + 0x30);

  uart_putc(':');

  uart_putc((seconds >> 4) + 0x30);

  uart_putc((seconds & 0x0F) + 0x30);

  uart_puts("     -");

  switch(day)

  {

    case 1:

      uart_puts("Montag, d.");

      break;

    case 2:

      uart_puts("Dienstag, d.");

      break;

    case 3:

      uart_puts("Mittwoch, d.");

      break;

    case 4:

      uart_puts("Donnerstag, d.");

      break;

    case 5:

      uart_puts("Freitag, d.");

      break;

    case 6:

      uart_puts("Samstag, d.");

      break;

    case 7:

      uart_puts("Sonntag, d.");

      break;

  }

  // tag

  uart_putc((day >> 4) + 0x30);

  uart_putc((day & 0x0F) + 0x30);

  uart_putc(':');

  // monat

  uart_putc((month >> 4) + 0x30);

  uart_putc((month & 0x0F) + 0x30);

  uart_putc(':');

  // jahr

  uart_putc((year >> 4) + 0x30);

  uart_putc((year & 0xF0) + 0x30);

  uart_putc(10);

  uart_putc(13);

}