static void readFrom(uint8_t address, uint8_t num) {
  // address to read from
  aTxBuffer[0] = address;

  /*##-2- Start the transmission process #####################################*/
  /* While the I2C in reception process, user can transmit data through
     "aTxBuffer" buffer */
  while(HAL_I2C_Master_Transmit_DMA(&I2cHandle, I2C_ADDRESS << 1, (uint8_t*)aTxBuffer, 1)!= HAL_OK)
  {
    /* Error_Handler() function is called when Timeout error occurs.
       When Acknowledge failure occurs (Slave don't acknowledge it's address)
       Master restarts communication */
    if (HAL_I2C_GetError(&I2cHandle) != HAL_I2C_ERROR_AF)
    {
      Error_Handler();
    }
  }

  /*##-3- Wait for the end of the transfer ###################################*/
  /*  Before starting a new communication transfer, you need to check the current
      state of the peripheral; if it�s busy you need to wait for the end of current
      transfer before starting a new one.
      For simplicity reasons, this example is just waiting till the end of the
      transfer, but application may perform other tasks while transfer operation
      is ongoing. */
  while (HAL_I2C_GetState(&I2cHandle) != HAL_I2C_STATE_READY)
  {
  }

  // request 6 bytes from device

  /*##-4- Put I2C peripheral in reception process ############################*/
  while(HAL_I2C_Master_Receive_DMA(&I2cHandle, I2C_ADDRESS << 1, (uint8_t *)aRxBuffer, 6) != HAL_OK)
  {
    /* Error_Handler() function is called when Timeout error occurs.
       When Acknowledge failure occurs (Slave don't acknowledge it's address)
       Master restarts communication */
    if (HAL_I2C_GetError(&I2cHandle) != HAL_I2C_ERROR_AF)
    {
      Error_Handler();
    }
  }

  /*##-5- Wait for the end of the transfer ###################################*/
  /*  Before starting a new communication transfer, you need to check the current
      state of the peripheral; if it�s busy you need to wait for the end of current
      transfer before starting a new one.
      For simplicity reasons, this example is just waiting till the end of the
      transfer, but application may perform other tasks while transfer operation
      is ongoing. */
  while (HAL_I2C_GetState(&I2cHandle) != HAL_I2C_STATE_READY)
  {
  }
}

/**
 * @brief  Configures I2C interface
 * @retval HAL status
 */
static HAL_StatusTypeDef I2C_EXPBD_Init(void)
{
    HAL_StatusTypeDef ret_val = HAL_OK;

    if(HAL_I2C_GetState(&I2C_EXPBD_Handle) == HAL_I2C_STATE_RESET)
    {
        /* I2C_EXPBD peripheral configuration */
#if ((defined (USE_STM32F4XX_NUCLEO)) || (defined (USE_STM32L1XX_NUCLEO)))
        I2C_EXPBD_Handle.Init.ClockSpeed = NUCLEO_I2C_EXPBD_SPEED;
        I2C_EXPBD_Handle.Init.DutyCycle = I2C_DUTYCYCLE_2;
#endif

#if (defined (USE_STM32L0XX_NUCLEO))
        I2C_EXPBD_Handle.Init.Timing = NUCLEO_I2C_EXPBD_TIMING_400KHZ;                            /* 400KHz */
#endif
        I2C_EXPBD_Handle.Init.OwnAddress1 = 0x33;
        I2C_EXPBD_Handle.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
        I2C_EXPBD_Handle.Instance = NUCLEO_I2C_EXPBD;

        /* Init the I2C */
        I2C_EXPBD_MspInit();
        ret_val = HAL_I2C_Init(&I2C_EXPBD_Handle);
    }

    return ret_val;
}

/**
 * @brief  Configures I2C interface
 * @param  None
 * @retval HAL status
 */
static HAL_StatusTypeDef I2C_SHIELDS_Init(void)
{
    HAL_StatusTypeDef ret_val = HAL_OK;
  
    if(HAL_I2C_GetState(&I2C_SHIELDS_Handle) == HAL_I2C_STATE_RESET)
    {
        /* I2C_SHIELDS peripheral configuration */
      //  I2C_SHIELDS_Handle.Init.ClockSpeed = NUCLEO_I2C_SHIELDS_SPEED;
      //  I2C_SHIELDS_Handle.Init.DutyCycle = I2C_DUTYCYCLE_2;
#ifdef STM32F401xE      
        I2C_SHIELDS_Handle.Init.ClockSpeed = NUCLEO_I2C_SHIELDS_SPEED;
        I2C_SHIELDS_Handle.Init.DutyCycle = I2C_DUTYCYCLE_2;
#endif
#ifdef STM32L053xx
        I2C_SHIELDS_Handle.Init.Timing = 0x0070D8FF;                            /*Refer AN4235-Application note Document*/
#endif        
        I2C_SHIELDS_Handle.Init.OwnAddress1 = 0x33;
        I2C_SHIELDS_Handle.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
        I2C_SHIELDS_Handle.Instance = NUCLEO_I2C_SHIELDS;

        /* Init the I2C */
        I2C_SHIELDS_MspInit();
        ret_val = HAL_I2C_Init(&I2C_SHIELDS_Handle);
    }
    
    return ret_val;
}

int initMPU(void){
	int initOkay = -1;
	HAL_I2C_StateTypeDef state;
	uint8_t tempByte = 13;
	uint8_t buffer[10] = {0,0,0,0,0,0,0,0,0,0};
	hnd.Instance = I2C1;
	hnd.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
	hnd.Init.ClockSpeed	= 400000;
	hnd.Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;
	hnd.Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;
	hnd.Init.DutyCycle = I2C_DUTYCYCLE_2;
	hnd.Init.NoStretchMode = I2C_NOSTRETCH_DISABLE;
	hnd.Init.OwnAddress1 = 0x00;
	
	HAL_I2C_Init(&hnd);
	__HAL_I2C_ENABLE(&hnd);
	state = HAL_I2C_GetState(&hnd); 
	if(state == HAL_I2C_STATE_READY){
		initOkay = 0;
	}
	buffer[0]=MPU6050_RA_PWR_MGMT_1;
	buffer[1]=0x80;
	printf("READ: %u",SCCB_Read(MPU6050_RA_WHO_AM_I));
	printf("error: %u",HAL_I2C_GetError(&hnd));
	return initOkay;

}

void AP_ReadBuffer(uint8_t RegAddr, uint8_t *aRxBuffer, uint8_t RXBUFFERSIZE)
{
    /* -> Lets ask for register's address */
    AP_WriteBuffer(&RegAddr, 1);
 
    /* -> Put I2C peripheral in reception process */
    while(HAL_I2C_Master_Receive(&AP_I2C_HANDLE, AP_I2C_ADDR, aRxBuffer, (uint16_t)RXBUFFERSIZE, (uint32_t)1000) != HAL_OK)
    {
        /* Error_Handler() function is called when Timeout error occurs.
         * When Acknowledge failure occurs (Slave don't acknowledge it's address)
         * Master restarts communication
         */
        if (HAL_I2C_GetError(&AP_I2C_HANDLE) != HAL_I2C_ERROR_AF)
        {
            //DEBUG(3, "In I2C::WriteBuffer -> error");
            //Error_Handler(4);
					PUTZ_ASSERT(false);
        }
    }
 
    /* -> Wait for the end of the transfer */
    /* Before starting a new communication transfer, you need to check the current
     * state of the peripheral; if it’s busy you need to wait for the end of current
     * transfer before starting a new one.
     * For simplicity reasons, this example is just waiting till the end of the
     * transfer, but application may perform other tasks while transfer operation
     * is ongoing.
     **/
    while (HAL_I2C_GetState(&AP_I2C_HANDLE) != HAL_I2C_STATE_READY)
    {
    }
}

void AP_WriteBuffer(uint8_t *aTxBuffer, uint8_t TXBUFFERSIZE) 
{
    /* -> Start the transmission process */
    /* While the I2C in reception process, user can transmit data through "aTxBuffer" buffer */
    while(HAL_I2C_Master_Transmit(&AP_I2C_HANDLE, AP_I2C_ADDR, (uint8_t*)aTxBuffer, (uint16_t)TXBUFFERSIZE, (uint32_t)1000)!= HAL_OK)
    {
        /*
         * Error_Handler() function is called when Timeout error occurs.
         * When Acknowledge failure occurs (Slave don't acknowledge it's address)
         * Master restarts communication
         */
 
        if (HAL_I2C_GetError(&AP_I2C_HANDLE) != HAL_I2C_ERROR_AF)
        {
            //DEBUG(3, "In I2C::WriteBuffer -> error");
            //Error_Handler(3);
        }
 
    }
 
    /* -> Wait for the end of the transfer */
    /* Before starting a new communication transfer, you need to check the current
     * state of the peripheral; if it’s busy you need to wait for the end of current
     * transfer before starting a new one.
     * For simplicity reasons, this example is just waiting till the end of the
     * transfer, but application may perform other tasks while transfer operation
     * is ongoing.
     */
      while (HAL_I2C_GetState(&AP_I2C_HANDLE) != HAL_I2C_STATE_READY)
      {
      }
}

/**
  * @brief I2C1 Bus Deinitialization
  * @retval None
  */
static void I2C1_DeInit(void)
{
  if(HAL_I2C_GetState(&heval_I2c1) != HAL_I2C_STATE_RESET)
  {
    /* DeInit the I2C */
    HAL_I2C_DeInit(&heval_I2c1);
    I2C1_MspDeInit(&heval_I2c1);
  }
}

//get DATA
static char getData(void)
{
	// I2C
	uint8_t aRxBuffer[1];

	HAL_I2C_Master_Receive_DMA(&hi2c1, (uint16_t)65, (uint8_t *)aRxBuffer, 1);
	while (HAL_I2C_GetState(&hi2c1) != HAL_I2C_STATE_READY)
	{
	}
	return aRxBuffer[0];
}

STATIC HAL_StatusTypeDef i2c_wait_dma_finished(I2C_HandleTypeDef *i2c, uint32_t timeout) {
    // Note: we can't use WFI to idle in this loop because the DMA completion
    // interrupt may occur before the WFI.  Hence we miss it and have to wait
    // until the next sys-tick (up to 1ms).
    uint32_t start = HAL_GetTick();
    while (HAL_I2C_GetState(i2c) != HAL_I2C_STATE_READY) {
        if (HAL_GetTick() - start >= timeout) {
            return HAL_TIMEOUT;
        }
    }
    return HAL_OK;
}

void i2c (){

		
	I2C_tx_buffer[0]=(uint8_t)MODE;
	
	HAL_I2C_Master_Transmit(&hi2c1, (uint16_t) I2C_ADDRESS, &I2C_tx_buffer[0], 1,100);
	//HAL_Delay(10);
	HAL_GPIO_TogglePin(Kimenet_GPIO_Port,Kimenet_Pin);
		//HAL_I2C_Master_Transmit_IT(&hi2c1, (uint16_t) I2C_ADDRESS, &I2C_tx_buffer[0], 1);
		while (HAL_I2C_GetState(&hi2c1) != HAL_I2C_STATE_READY); //waiting for the end of current transfer before starting a new one
	

		HAL_I2C_Master_Receive(&hi2c1, (uint16_t) I2C_ADDRESS, &I2C_rx_buffer[0], 1,100);
		while (HAL_I2C_GetState(&hi2c1) != HAL_I2C_STATE_READY); //waiting for the end of current transfer

	for(int i=0;i<10;i++){
		HAL_GPIO_TogglePin(Kimenet_GPIO_Port,Kimenet_Pin);
		HAL_Delay (500);
	}
	
}

/**
  * @brief  Configures I2C interface.
  * @param  None
  * @retval None
  */
static void I2Cx_Init(void)
{
  if(HAL_I2C_GetState(&I2cHandle) == HAL_I2C_STATE_RESET)
  {
    /* DISCOVERY_I2Cx peripheral configuration */
    I2cHandle.Init.ClockSpeed = 10000;
    I2cHandle.Init.DutyCycle = I2C_DUTYCYCLE_2;
    I2cHandle.Init.OwnAddress1 = 0x33;
    I2cHandle.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
    I2cHandle.Instance = DISCOVERY_I2Cx;
      
    /* Init the I2C */
    I2Cx_MspInit();
    HAL_I2C_Init(&I2cHandle);
  }
}

/**
  * @brief Discovery I2Cx Bus initialization
  * @param None
  * @retval None
  */
void I2Cbar_Init(void)
{
  if(HAL_I2C_GetState(&I2CbarHandle) == HAL_I2C_STATE_RESET)
  {
    I2CbarHandle.Instance = DISCOVERY_I2Cbar;
    I2CbarHandle.Init.OwnAddress1 =  BAROMETER_I2C_ADDRESS;
    I2CbarHandle.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
    I2CbarHandle.Init.DualAddressMode = I2C_DUALADDRESS_DISABLED;
    I2CbarHandle.Init.OwnAddress2 = 0;
    I2CbarHandle.Init.GeneralCallMode = I2C_GENERALCALL_DISABLED;
    I2CbarHandle.Init.NoStretchMode = I2C_NOSTRETCH_DISABLED;

    /* Init the I2C */
    I2Cbar_MspInit();
    HAL_I2C_Init(&I2CbarHandle);
  }
}

/**
  * @brief Eval I2Cx Bus initialization
  * @param None
  * @retval None
  */
static void I2Cx_Init(void)
{
  if(HAL_I2C_GetState(&heval_I2c) == HAL_I2C_STATE_RESET)
  {
    heval_I2c.Instance              = EVAL_I2Cx;
    heval_I2c.Init.Timing           = EVAL_I2Cx_TIMING;
    heval_I2c.Init.OwnAddress1      = 0;
    heval_I2c.Init.AddressingMode   = I2C_ADDRESSINGMODE_7BIT;
    heval_I2c.Init.DualAddressMode  = I2C_DUALADDRESS_DISABLED;
    heval_I2c.Init.OwnAddress2      = 0;
    heval_I2c.Init.GeneralCallMode  = I2C_GENERALCALL_DISABLED;
    heval_I2c.Init.NoStretchMode    = I2C_NOSTRETCH_DISABLED;  

    /* Init the I2C */
    I2Cx_MspInit(&heval_I2c);
    HAL_I2C_Init(&heval_I2c);
  }
}

/**
  * @brief I2C Bus initialization
  * @param None
  * @retval None
  */
void I2C1_Init(void)
{
  if(HAL_I2C_GetState(&heval_I2c1) == HAL_I2C_STATE_RESET)
  {
    heval_I2c1.Instance              = BSP_I2C1;
    heval_I2c1.Init.Timing           = I2C1_TIMING;
    heval_I2c1.Init.OwnAddress1      = 0;
    heval_I2c1.Init.AddressingMode   = I2C_ADDRESSINGMODE_7BIT;
    heval_I2c1.Init.DualAddressMode  = I2C_DUALADDRESS_DISABLE;
    heval_I2c1.Init.OwnAddress2      = 0;
    heval_I2c1.Init.OwnAddress2Masks = I2C_OA2_NOMASK;
    heval_I2c1.Init.GeneralCallMode  = I2C_GENERALCALL_DISABLE;
    heval_I2c1.Init.NoStretchMode    = I2C_NOSTRETCH_DISABLE;  

    /* Init the I2C */
    I2C1_MspInit(&heval_I2c1);
    HAL_I2C_Init(&heval_I2c1);
  }
}

/**
  * @brief  I2Cx Bus initialization.
  */
static void I2Cx_Init(void)
{
  if(HAL_I2C_GetState(&I2cHandle) == HAL_I2C_STATE_RESET)
  {
    I2cHandle.Instance              = DISCOVERY_I2Cx;
    I2cHandle.Init.ClockSpeed       = BSP_I2C_SPEED;
    I2cHandle.Init.DutyCycle        = I2C_DUTYCYCLE_2;
    I2cHandle.Init.OwnAddress1      = 0;
    I2cHandle.Init.AddressingMode   = I2C_ADDRESSINGMODE_7BIT;
    I2cHandle.Init.DualAddressMode  = I2C_DUALADDRESS_DISABLED;
    I2cHandle.Init.OwnAddress2      = 0;
    I2cHandle.Init.GeneralCallMode  = I2C_GENERALCALL_DISABLED;
    I2cHandle.Init.NoStretchMode    = I2C_NOSTRETCH_DISABLED;  
    
    /* Init the I2C */
    I2Cx_MspInit(&I2cHandle);
    HAL_I2C_Init(&I2cHandle);
  }
}

/**
  * @brief  Main program
  * @param  None
  * @retval None
  */
int main(void)
{
#ifdef MASTER_BOARD
  GPIO_InitTypeDef  GPIO_InitStruct;
#endif
  
  /* STM32F3xx HAL library initialization:
       - Configure the Flash prefetch
       - Configure the Systick to generate an interrupt each 1 msec
       - Set NVIC Group Priority to 4
       - Low Level Initialization
     */
  HAL_Init();
  
  /* Configure the system clock to 64 MHz */
  SystemClock_Config();
  
  /* Configure LED3 and LED3*/
  BSP_LED_Init(LED3);
  
  /*##-1- Configure the I2C peripheral ######################################*/
  I2cHandle.Instance             = I2Cx;
  
  I2cHandle.Init.Timing          = I2C_TIMING;
  I2cHandle.Init.OwnAddress1     = I2C_ADDRESS;
  I2cHandle.Init.AddressingMode  = I2C_ADDRESSINGMODE_7BIT;
  I2cHandle.Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;
  I2cHandle.Init.OwnAddress2     = 0xFF;
  I2cHandle.Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;
  I2cHandle.Init.NoStretchMode   = I2C_NOSTRETCH_DISABLE;  
  
  if(HAL_I2C_Init(&I2cHandle) != HAL_OK)
  {
    /* Initialization Error */
    Error_Handler();    
  }

  /* Enable the Analog I2C Filter */
  HAL_I2CEx_ConfigAnalogFilter(&I2cHandle,I2C_ANALOGFILTER_ENABLE);
  
#ifdef MASTER_BOARD
  
  /* Configure PA.12 (Arduino D2) button */
  GPIO_InitStruct.Pin = GPIO_PIN_12;
  GPIO_InitStruct.Pull = GPIO_PULLUP;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT; 
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
    
  /* Enable GPIOA clock */
  __HAL_RCC_GPIOA_CLK_ENABLE();

  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
  /* Wait Until PA.12 (Arduino D2) is connected to GND */
  while(HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_12) != GPIO_PIN_RESET) 
  {
  }  
  /* Wait Until PA.12 (Arduino D2) is de-connected from GND */
  while(HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_12) != GPIO_PIN_SET)
  {
  } 

  /* The board sends the message and expects to receive it back */
  
  /*##-2- Start the transmission process #####################################*/  
  /* While the I2C in reception process, user can transmit data through 
     "aTxBuffer" buffer */
  while(HAL_I2C_Master_Transmit_IT(&I2cHandle, (uint16_t)I2C_ADDRESS, (uint8_t*)aTxBuffer, TXBUFFERSIZE)!= HAL_OK)
  {
    /* Error_Handler() function is called when Timeout error occurs.
       When Acknowledge failure occurs (Slave don't acknowledge its address)
       Master restarts communication */
    if (HAL_I2C_GetError(&I2cHandle) != HAL_I2C_ERROR_AF)
    {
      Error_Handler();
    }
  }
  
  /*##-3- Wait for the end of the transfer ###################################*/  
  /*  Before starting a new communication transfer, you need to check the current   
      state of the peripheral; if it’s busy you need to wait for the end of current
      transfer before starting a new one.
      For simplicity reasons, this example is just waiting till the end of the 
      transfer, but application may perform other tasks while transfer operation
      is ongoing. */  
  while (HAL_I2C_GetState(&I2cHandle) != HAL_I2C_STATE_READY)
  {
  } 
  
  HAL_Delay(1000);

  /* Wait Until PA.12 (Arduino D2) is connected to GND */
  while(HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_12) != GPIO_PIN_RESET) 
  {
  }  
  /* Wait Until PA.12 (Arduino D2) is de-connected from GND */
//.........这里部分代码省略.........

/**
  * @brief  Main program
  * @param  None
  * @retval None
  */
int main(void)
{

    /* STM32F3xx HAL library initialization:
         - Configure the Flash prefetch
         - Configure the Systick to generate an interrupt each 1 msec
         - Set NVIC Group Priority to 4
         - Low Level Initialization
       */
    HAL_Init();

    /* Configure the system clock to 64 MHz */
    SystemClock_Config();

    /* Configure LED1 and LED3 */
    BSP_LED_Init(LED1);
    BSP_LED_Init(LED3);


    /*##-1- Configure the I2C peripheral ######################################*/
    I2cHandle.Instance             = I2Cx;
    I2cHandle.Init.Timing          = I2C_TIMING;
    I2cHandle.Init.OwnAddress1     = I2C_ADDRESS;
    I2cHandle.Init.AddressingMode  = I2C_ADDRESSINGMODE_10BIT;
    I2cHandle.Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;
    I2cHandle.Init.OwnAddress2     = 0xFF;
    I2cHandle.Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;
    I2cHandle.Init.NoStretchMode   = I2C_NOSTRETCH_DISABLE;

    if(HAL_I2C_Init(&I2cHandle) != HAL_OK)
    {
        /* Initialization Error */
        Error_Handler();
    }

    /* Enable the Analog I2C Filter */
    HAL_I2CEx_ConfigAnalogFilter(&I2cHandle,I2C_ANALOGFILTER_ENABLE);

#ifdef MASTER_BOARD

    /* Configure User push-button button */
    BSP_PB_Init(BUTTON_USER,BUTTON_MODE_GPIO);

    /* Wait for User push-button press before starting the Communication */
    while (BSP_PB_GetState(BUTTON_USER) != GPIO_PIN_SET)
    {
    }

    /* Delay to avoid that possible signal rebound is taken as button release */
    HAL_Delay(50);

    /* Wait for User push-button release before starting the Communication */
    while (BSP_PB_GetState(BUTTON_USER) != GPIO_PIN_RESET)
    {
    }


    /* The board sends the message and expects to receive it back */

    /*##-2- Start the transmission process #####################################*/
    /* While the I2C in reception process, user can transmit data through
       "aTxBuffer" buffer */
    while(HAL_I2C_Master_Transmit_IT(&I2cHandle, (uint16_t)I2C_ADDRESS, (uint8_t*)aTxBuffer, TXBUFFERSIZE)!= HAL_OK)
    {
        /* Error_Handler() function is called when Timeout error occurs.
           When Acknowledge failure occurs (Slave don't acknowledge its address)
           Master restarts communication */
        if (HAL_I2C_GetError(&I2cHandle) != HAL_I2C_ERROR_AF)
        {
            Error_Handler();
        }
    }

    /*##-3- Wait for the end of the transfer ###################################*/
    /*  Before starting a new communication transfer, you need to check the current
        state of the peripheral; if it’s busy you need to wait for the end of current
        transfer before starting a new one.
        For simplicity reasons, this example is just waiting till the end of the
        transfer, but application may perform other tasks while transfer operation
        is ongoing. */
    while (HAL_I2C_GetState(&I2cHandle) != HAL_I2C_STATE_READY)
    {
    }

    /* Wait for User push-button press before starting the Communication */
    while (BSP_PB_GetState(BUTTON_USER) != GPIO_PIN_SET)
    {
    }

    /* Delay to avoid that possible signal rebound is taken as button release */
    HAL_Delay(50);

    /* Wait for User push-button release before starting the Communication */
    while (BSP_PB_GetState(BUTTON_USER) != GPIO_PIN_RESET)
    {
//.........这里部分代码省略.........

/**
  * @brief  Main program
  * @param  None
  * @retval None
  */
int main(void)
{
  /* STM32F2xx HAL library initialization:
       - Configure the Flash prefetch, instruction and Data caches
       - Configure the Systick to generate an interrupt each 1 msec
       - Set NVIC Group Priority to 4
       - Global MSP (MCU Support Package) initialization
     */
  HAL_Init();
  
  /* Configure LED1 and LED2 */
  BSP_LED_Init(LED1);
  BSP_LED_Init(LED2);
  
  /* Configure the system clock to 120 MHz */
  SystemClock_Config();

  /*##-1- Configure the I2C peripheral #######################################*/
  I2CxHandle.Instance             = I2Cx;
  I2CxHandle.Init.AddressingMode  = I2C_ADDRESSINGMODE_7BIT;
  I2CxHandle.Init.ClockSpeed      = 400000;
  I2CxHandle.Init.DualAddressMode = I2C_DUALADDRESS_DISABLED;
  I2CxHandle.Init.DutyCycle       = I2C_DUTYCYCLE_16_9;
  I2CxHandle.Init.GeneralCallMode = I2C_GENERALCALL_DISABLED;
  I2CxHandle.Init.NoStretchMode   = I2C_NOSTRETCH_DISABLED;
  I2CxHandle.Init.OwnAddress1     = I2C_ADDRESS;
  I2CxHandle.Init.OwnAddress2     = 0;

  if(HAL_I2C_Init(&I2CxHandle) != HAL_OK)
  {
    /* Initialization Error */
    Error_Handler();
  }

#ifdef MASTER_BOARD
  /* Configure User Button */
  BSP_PB_Init(BUTTON_KEY, BUTTON_MODE_GPIO);

  /* Wait for User Button press before starting the Communication */
  while (BSP_PB_GetState(BUTTON_KEY) != 1)
  {
  }

  /* Wait for User Button release before starting the Communication */
  while (BSP_PB_GetState(BUTTON_KEY) != 0)
  {
  }

  while(1)
  {
    /* Initialize number of data variables */
    hTxNumData = TXBUFFERSIZE;
    hRxNumData = RXBUFFERSIZE;

    /* Update bTransferRequest to send buffer write request for Slave */
    bTransferRequest = MASTER_REQ_WRITE;

    /*##-2- Master sends write request for slave #############################*/
    while(HAL_I2C_Master_Transmit_IT(&I2CxHandle, (uint16_t)I2C_ADDRESS, (uint8_t*)&bTransferRequest, 1)!= HAL_OK)
    {
      /* Error_Handler() function is called when Timout error occurs.
         When Acknowledge failure ocucurs (Slave don't acknowledge it's address)
         Master restarts communication */
      if (HAL_I2C_GetError(&I2CxHandle) != HAL_I2C_ERROR_AF)
      {
        Error_Handler();
      }
    }

    /*  Before starting a new communication transfer, you need to check the current
    state of the peripheral; if it’s busy you need to wait for the end of current
    transfer before starting a new one.
    For simplicity reasons, this example is just waiting till the end of the
    transfer, but application may perform other tasks while transfer operation
    is ongoing. */
    while (HAL_I2C_GetState(&I2CxHandle) != HAL_I2C_STATE_READY)
    {
    }

    /*##-3- Master sends number of data to be written ########################*/
    while(HAL_I2C_Master_Transmit_IT(&I2CxHandle, (uint16_t)I2C_ADDRESS, (uint8_t*)&hTxNumData, 2)!= HAL_OK)
    {
      /* Error_Handler() function is called when Timout error occurs.
         When Acknowledge failure ocucurs (Slave don't acknowledge it's address)
         Master restarts communication */
      if (HAL_I2C_GetError(&I2CxHandle) != HAL_I2C_ERROR_AF)
      {
        Error_Handler();
      }
    }

    /*  Before starting a new communication transfer, you need to check the current
    state of the peripheral; if it’s busy you need to wait for the end of current
    transfer before starting a new one.
    For simplicity reasons, this example is just waiting till the end of the
//.........这里部分代码省略.........

/**
  * @brief  Main program
  * @param  None
  * @retval None
  */
int main(void)
{
  /* STM32F0xx HAL library initialization:
       - Configure the Flash prefetch
       - Systick timer is configured by default as source of time base, but user 
         can eventually implement his proper time base source (a general purpose 
         timer for example or other time source), keeping in mind that Time base 
         duration should be kept 1ms since PPP_TIMEOUT_VALUEs are defined and 
         handled in milliseconds basis.
       - Low Level Initialization
     */
  HAL_Init();

  /* Configure the system clock to 48 MHz */
  SystemClock_Config();

  /* Configure LED5, LED4 and LED3 */
  BSP_LED_Init(LED5);
  BSP_LED_Init(LED4);
  BSP_LED_Init(LED3);

  /*##-1- Configure the I2C peripheral #######################################*/
  I2cHandle.Instance             = I2Cx;

  I2cHandle.Init.AddressingMode  = I2C_ADDRESSINGMODE_7BIT;
  I2cHandle.Init.Timing          = I2Cx_TIMING;
  I2cHandle.Init.DualAddressMode = I2C_DUALADDRESS_DISABLED;
  I2cHandle.Init.OwnAddress1     = 0;
  I2cHandle.Init.OwnAddress2     = 0;
  I2cHandle.Init.GeneralCallMode = I2C_GENERALCALL_DISABLED;
  I2cHandle.Init.NoStretchMode   = I2C_NOSTRETCH_DISABLED;

  if (HAL_I2C_Init(&I2cHandle) != HAL_OK)
  {
    /* Initialization Error */
    Error_Handler();
  }

  /* The board sends the message to EEPROM then reads it back */

  /*##-2- Start writing process ##############################################*/
  /* Initialize Remaining Bytes Value to TX Buffer Size */
  Remaining_Bytes = TXBUFFERSIZE;
  /* Initialize Memory address to 0 since EEPROM write will start from address 0 */
  Memory_Address = 0;
  /* Since page size is 4 bytes, the write procedure will be done in a loop */
  while (Remaining_Bytes > 0)
  {
    /* Write 4 bytes */
    if (HAL_I2C_Mem_Write_DMA(&I2cHandle, (uint16_t)I2C_ADDRESS, Memory_Address, I2C_MEMADD_SIZE_16BIT, (uint8_t *)(aTxBuffer + Memory_Address), 4) != HAL_OK)
    {
      /* Writing process Error */
      Error_Handler();
    }

    /* Wait for the end of the transfer */
    while (HAL_I2C_GetState(&I2cHandle) != HAL_I2C_STATE_READY)
    {
    }

    /* Check if the EEPROM is ready for a new operation */
    while (HAL_I2C_IsDeviceReady(&I2cHandle, I2C_ADDRESS, 20, 300) == HAL_TIMEOUT);

    /* Wait for the end of the transfer */
    while (HAL_I2C_GetState(&I2cHandle) != HAL_I2C_STATE_READY)
    {
    }

    /* Update Remaining bytes and Memory Address values */
    Remaining_Bytes -= 4;
    Memory_Address += 4;
  }

  /*##-3- Start reading process ##############################################*/
  if (HAL_I2C_Mem_Read_DMA(&I2cHandle, (uint16_t)I2C_ADDRESS, 0, I2C_MEMADD_SIZE_16BIT, (uint8_t *)aRxBuffer, RXBUFFERSIZE) != HAL_OK)
  {
    /* Reading process Error */
    Error_Handler();
  }

  /* Wait for the end of the transfer */
  while (HAL_I2C_GetState(&I2cHandle) != HAL_I2C_STATE_READY)
  {
  }

  /*##-4- Compare the sent and received buffers ##############################*/
  if (Buffercmp((uint8_t *)aTxBuffer, (uint8_t *)aRxBuffer, RXBUFFERSIZE))
  {
    /* Processing Error */
    Error_Handler();
  }

  /* Infinite loop */
  while (1)
  {
//.........这里部分代码省略.........

/**
  * @brief  Main program
  * @param  None
  * @retval None
  */
int main(void)
{
  /* STM32F3xx HAL library initialization:
       - Configure the Flash prefetch
       - Systick timer is configured by default as source of time base, but user 
         can eventually implement his proper time base source (a general purpose 
         timer for example or other time source), keeping in mind that Time base 
         duration should be kept 1ms since PPP_TIMEOUT_VALUEs are defined and 
         handled in milliseconds basis.
       - Set NVIC Group Priority to 4
       - Low Level Initialization
     */
  HAL_Init();
  
  /* Configure the system clock to 72 MHz */
  SystemClock_Config();
  
  /* Configure LED7, LED3 and LED9*/
  BSP_LED_Init(LED7);
  BSP_LED_Init(LED3);
  BSP_LED_Init(LED9);
  
  /*##-1- Configure the I2C peripheral ######################################*/
  I2cHandle.Instance             = I2Cx;
  
  I2cHandle.Init.Timing          = I2C_TIMING;
  I2cHandle.Init.OwnAddress1     = I2C_ADDRESS;
  I2cHandle.Init.AddressingMode  = I2C_ADDRESSINGMODE_7BIT;
  I2cHandle.Init.DualAddressMode = I2C_DUALADDRESS_DISABLED;
  I2cHandle.Init.OwnAddress2     = 0xFF;
  I2cHandle.Init.GeneralCallMode = I2C_GENERALCALL_DISABLED;
  I2cHandle.Init.NoStretchMode   = I2C_NOSTRETCH_DISABLED;  
  
  if(HAL_I2C_Init(&I2cHandle) != HAL_OK)
  {
    /* Initialization Error */
    Error_Handler();    
  }

  /* Enable the Analog I2C Filter */
  HAL_I2CEx_AnalogFilter_Config(&I2cHandle,I2C_ANALOGFILTER_ENABLED);
  
#ifdef MASTER_BOARD
  
  /* Configure USER Button*/
  BSP_PB_Init(BUTTON_USER, BUTTON_MODE_GPIO);

  /* Wait for USER Button press before starting the Communication */
  while (BSP_PB_GetState(BUTTON_USER) != GPIO_PIN_RESET)
  {
  }
  
  /* Wait for USER Button release before starting the Communication */
  while (BSP_PB_GetState(BUTTON_USER) != GPIO_PIN_SET)
  {
  }
  
  /* The board sends the message and expects to receive it back */
  
  /*##-2- Start the transmission process #####################################*/  
  /* While the I2C in reception process, user can transmit data through 
     "aTxBuffer" buffer */
  while(HAL_I2C_Master_Transmit_IT(&I2cHandle, (uint16_t)I2C_ADDRESS, (uint8_t*)aTxBuffer, TXBUFFERSIZE)!= HAL_OK)
  {
    /* Error_Handler() function is called when Timout error occurs.
       When Acknowledge failure ocucurs (Slave don't acknowledge it's address)
       Master restarts communication */
    if (HAL_I2C_GetError(&I2cHandle) != HAL_I2C_ERROR_AF)
    {
      Error_Handler();
    }
  }
  
  /*##-3- Wait for the end of the transfer ###################################*/  
  /*  Before starting a new communication transfer, you need to check the current   
      state of the peripheral; if it’s busy you need to wait for the end of current
      transfer before starting a new one.
      For simplicity reasons, this example is just waiting till the end of the 
      transfer, but application may perform other tasks while transfer operation
      is ongoing. */  
  while (HAL_I2C_GetState(&I2cHandle) != HAL_I2C_STATE_READY)
  {
  } 
  
  /* Wait for USER Button press before starting the Communication */
  while (BSP_PB_GetState(BUTTON_USER) != GPIO_PIN_RESET)
  {
  }

  /* Wait for USER Button release before starting the Communication */
  while (BSP_PB_GetState(BUTTON_USER) != GPIO_PIN_SET)
  {
  }

  /*##-4- Put I2C peripheral in reception process ###########################*/  
//.........这里部分代码省略.........