void i2c_waitForIdle()
{
while (( SSPCON2 & 0x1F ) | SSPSTATbits.R_nW ) {}; // wait for idle and not writing
}

int i2c_read( unsigned char ack )
{
unsigned char i2cReadData;

i2c_waitForIdle();
SSPCON2bits.RCEN=1;
i2c_waitForIdle();
i2cReadData = SSPBUF;
i2c_waitForIdle();
if ( ack )
  {SSPCON2bits.ACKDT=0;}
else
  {SSPCON2bits.ACKDT=1;}
  SSPCON2bits.ACKEN=1;               // send acknowledge sequence
return( i2cReadData );
}

unsigned char i2c_write( unsigned char i2cWriteData )
{
i2c_waitForIdle();
SSPBUF = i2cWriteData;
return ( !SSPCON2bits.ACKSTAT  ); // function returns '1' if transmission is acknowledged
}


void ds1307_get_date(unsigned short *day, unsigned short *mth, unsigned short *year, unsigned short *dow)
{
  i2c_start();
  i2c_write(0xD0);
  i2c_write(0x03);            // Start at REG 3 - Day of week
  i2c_start();
  i2c_write(0xD1);
  *dow  = bcd2bin(i2c_read(1) & 0x7f);   // REG 3
  *day  = bcd2bin(i2c_read(1) & 0x3f);   // REG 4
  *mth  = bcd2bin(i2c_read(1) & 0x1f);   // REG 5
  *year = bcd2bin(i2c_read(0));          // REG 6
  i2c_stop();
}

void ds1307_get_time(unsigned short *hr, unsigned short *min, unsigned short *sec)
{
  i2c_start();
  i2c_write(0xD0);
  i2c_write(0x00);            // Start at REG 0 - Seconds
  i2c_start();
  i2c_write(0xD1);
  *sec = bcd2bin(i2c_read(1) & 0x7f);
  *min = bcd2bin(i2c_read(1) & 0x7f);
  *hr  = bcd2bin(i2c_read(0) & 0x3f);
  i2c_stop();
}