TM4C129的i2c有bug吗？

void I2CInit(void)
{
  MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_I2C2);  
  MAP_GPIOPinConfigure(GPIO_PL0_I2C2SDA); 
  MAP_GPIOPinTypeI2C(GPIO_PORTL_BASE, GPIO_PIN_0);  

  MAP_GPIOPinConfigure(GPIO_PL1_I2C2SCL);
  MAP_GPIOPinTypeI2CSCL(GPIO_PORTL_BASE, GPIO_PIN_1);  
  I2CMasterInitExpClk(I2C2_BASE, 120000000, 1);
  I2CMasterEnable(I2C2_BASE);
}

/*
*********************************************************************************************************
** 函数名称： FM24CL64WritePolled()
** 函数功能： 向FM24CL64写字符
** 入口参数：	pucdata     数据发送缓冲区指针
ucAddr      FM25CL64子地址
ulCount     写入的个数
** 出口参数   true        写入成功
false				写入失败
*********************************************************************************************************
*/
bool
FM24CL64Write(uint8_t fm24cl64_addr, uint32_t ucAddr, uint8_t *pucData, uint32_t ulCount)
{
  uint32_t ulToWrite;
  MAP_I2CMasterSlaveAddrSet(I2C2_BASE, fm24cl64_addr, false);
  ulToWrite = ulCount;
  MAP_I2CMasterDataPut(I2C2_BASE, ucAddr/256);
  MAP_I2CMasterControl(I2C2_BASE, I2C_MASTER_CMD_BURST_SEND_START);
  if(!WaitI2CFinished())
  {
    return(false);
  }  
  MAP_I2CMasterDataPut(I2C2_BASE, ucAddr%256);
  MAP_I2CMasterControl(I2C2_BASE, I2C_MASTER_CMD_BURST_SEND_CONT);
  if(!WaitI2CFinished())
  {
    return(false);
  }
  
  while(ulToWrite)
  {
    MAP_I2CMasterDataPut(I2C2_BASE, *pucData++);							
    if(ulToWrite)
    {
      MAP_I2CMasterControl(I2C2_BASE,
                           ((ulToWrite == 1) ? I2C_MASTER_CMD_BURST_SEND_FINISH : I2C_MASTER_CMD_BURST_SEND_CONT));
    }
    if(!WaitI2CFinished())
    {
      return(false);
    }
    ulToWrite--;
  }
  return(true);
}

/*
*********************************************************************************************************
** 函数名称： FM24CL64ReadPolled()
** 函数功能： 向FM24CL64读数据
** 入口参数：	pucdata     数据接收缓冲区指针
ulOffset    FM25CL64子地址
ulCount    	读出的个数
** 出口参数   true        读出成功
false				读出失败
*********************************************************************************************************
*/

bool
FM24CL64Read(uint8_t fm24cl64_addr, uint32_t ulOffset, uint8_t *pucData,
             uint32_t ulCount)
{
  uint32_t ulToRead;  
  I2CMasterSlaveAddrSet(I2C2_BASE, fm24cl64_addr, false);
  I2CMasterDataPut(I2C2_BASE, ulOffset/256);
  I2CMasterControl(I2C2_BASE, I2C_MASTER_CMD_BURST_SEND_START);
  if(!WaitI2CFinished())
  {
    return(false);
  }
  I2CMasterDataPut(I2C2_BASE, ulOffset%256);
  I2CMasterControl(I2C2_BASE, I2C_MASTER_CMD_BURST_SEND_CONT);
  if(!WaitI2CFinished())
  {
    return(false);
  }
  I2CMasterSlaveAddrSet(I2C2_BASE, fm24cl64_addr, true);
  I2CMasterControl(I2C2_BASE,
                   ((ulCount > 1) ? I2C_MASTER_CMD_BURST_RECEIVE_START :
                       I2C_MASTER_CMD_SINGLE_RECEIVE));
  ulToRead = ulCount;
  while(ulToRead)
  {
    if(!WaitI2CFinished())
    {
      return(false);
    }
    *pucData++ = I2CMasterDataGet(I2C2_BASE);
    ulToRead--;
    if(ulToRead)
    {
      I2CMasterControl(I2C2_BASE,
                       ((ulToRead == 1) ? I2C_MASTER_CMD_BURST_RECEIVE_FINISH : I2C_MASTER_CMD_BURST_RECEIVE_CONT));
    }
  }
  return(true);
}

bool
WaitI2CFinished(void)
{
  uint32_t wait_count = 0xffffff;
  while(MAP_I2CMasterBusy(I2C2_BASE)) 
  {
    if(wait_count == 0)
    {
      return false;
    }
    else
    {
      wait_count--;
    }    
  }  
  return true;
}

int main()
{
 uint8_t pucReadData[6]={0};
  uint8_t pucWriteData[6]={0};
  uint32_t index = 0;

g_ui32SysClock = SysCtlClockFreqSet((SYSCTL_XTAL_25MHZ|SYSCTL_OSC_MAIN|    SYSCTL_USE_PLL|SYSCTL_CFG_VCO_480), 120000000);
I2CInit();
  
  for(index=0; index<6; index++)
  {
    pucWriteData[index] = (0x09+index);
  }  
  while(1)
  { 
    SysCtlDelay(120000);
    FM24CL64Write(0x52, 0x00,pucWriteData, 3);
    SysCtlDelay(12000);
    FM24CL64Read(0x52, 0x00, pucReadData,3);
  }  
}

读写铁电单步调试FM24CL64Write和FM24CL64Read就可以正常读写，全速就不正确，后来经过各种调试发现在WaitI2CFinished函数里面加 SysCtlDelay(10);的延时就正常了，这到底是什么原因啊？是否存在这种bug？