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output of ds1307 to uart using 89v51rd2 is not correct

i have done the interface between ds1307 and 89v51rd2.the output to uart after reading time and date from the rtc ic not correct i am getting like Time=36:32:0D,Date=1F/1C/3F.can any one help me.

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0 rank amateur over 14 years ago in reply to Selim Sefraoui

unsigned int DS1307_get(unsigned char addr)
{
        unsigned int ret=0;

/* shouldn't you issue a start bit before the write ? */

        I2C_write(DS1307_ID);   /* Connect to DS1307 */
        I2C_write(addr);                /* Request RAM address on DS1307 */

        I2C_start();                    /* Start i2c bus */

        I2C_write(DS1307_ID+1); /* Connect to DS1307 for Read */
        ret = I2C_read();               /* Receive data */

        I2C_noack();

        I2C_stop();                             /* Stop i2c bus */

   return ((((ret>>4)&0x0F)*10)+(ret&0x0F));;
}

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0 rank amateur over 14 years ago in reply to Selim Sefraoui

unsigned int DS1307_get(unsigned char addr)
{
        unsigned int ret=0;

/* shouldn't you issue a start bit before the write ? */

        I2C_write(DS1307_ID);   /* Connect to DS1307 */
        I2C_write(addr);                /* Request RAM address on DS1307 */

        I2C_start();                    /* Start i2c bus */

        I2C_write(DS1307_ID+1); /* Connect to DS1307 for Read */
        ret = I2C_read();               /* Receive data */

        I2C_noack();

        I2C_stop();                             /* Stop i2c bus */

   return ((((ret>>4)&0x0F)*10)+(ret&0x0F));;
}

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