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Connecting DS1307 To LPC1768 not working

Question asked by navid ansari on Dec 2, 2017
Latest reply on Dec 5, 2017 by jeremyzhou


i connect ds1307 like this

battery is 3V and voltage on VCC is 5V . i connect another i2c device to i2c bus that its name is 24cxx 

24cxx vcc is 3.3 V . because its all open drain so i dont think it would be a problem to connect5 both of them to lpc1768

on keil for lpc1768 i connect to 24cxx and everything work right but when i try to connect to ds1307 its not happening

this is my code

#include "DS1307.h"
#include "Driver_I2C.h"
#include <string.h>
#include "cmsis_os.h"                   // ARM::CMSIS:RTOS:Keil RTX

/* I2C Driver */
extern ARM_DRIVER_I2C Driver_I2C0;
static ARM_DRIVER_I2C * DS1307I2Cdrv = &Driver_I2C0;

#define DS1307_I2C_ADDR       0xD0      /* DS1307 I2C address         */

#define A_WR                  0         /* Master will write to the I2C       */
#define A_RD                  1         /* Master will read from the I2C      */

static uint8_t DS1307DeviceAddr;
static uint8_t DS1307_wr_buf[58];

void DS1307Init(){
     DS1307I2Cdrv->Initialize   (NULL);
  DS1307I2Cdrv->PowerControl (ARM_POWER_FULL);
  DS1307I2Cdrv->Control      (ARM_I2C_BUS_CLEAR, 0);
     /* Init 24cxx EEPROM device */
  DS1307DeviceAddr = DS1307_I2C_ADDR;
     unsigned char temp[1] = {0};
     DS1307_WriteBuf(0 , temp , 1);


int32_t DS1307_ReadBuf (uint16_t addr, uint8_t *buf, uint32_t len) {
  uint8_t a[2];

  a[0] = (uint8_t)(addr >> 8);
  a[1] = (uint8_t)(addr & 0xFF);

  DS1307I2Cdrv->MasterTransmit (DS1307DeviceAddr, a, 2, true);
  while (DS1307I2Cdrv->GetStatus().busy);
  DS1307I2Cdrv->MasterReceive (DS1307DeviceAddr, buf, len, false);
  while (DS1307I2Cdrv->GetStatus().busy);
  if (DS1307I2Cdrv->GetDataCount () != len) return -1;

  return 0;

int32_t DS1307_WriteBuf (uint16_t addr, const uint8_t *buf, uint32_t len) {

  DS1307_wr_buf[0] = (uint8_t)(addr >> 8);
  DS1307_wr_buf[1] = (uint8_t)(addr & 0xFF);

  memcpy (&DS1307_wr_buf[2], &buf[0], len);

  DS1307I2Cdrv->MasterTransmit (DS1307DeviceAddr, DS1307_wr_buf, len + 2, false);
  while (DS1307I2Cdrv->GetStatus().busy);
  if (DS1307I2Cdrv->GetDataCount () != (len + 2)) return -1;
  /* Acknowledge polling */

  do {
    DS1307I2Cdrv->MasterReceive (DS1307DeviceAddr, &DS1307_wr_buf[0], 1, false);
    while (DS1307I2Cdrv->GetStatus().busy);
  } while (DS1307I2Cdrv->GetDataCount () < 0);

  return 0;


in logic analyzer i just recieve this

why i cant read or write anything to it?

its my main code


     state = DS1307_ReadBuf(0,mTime,1);