stm32f4xx_i2c.c

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/* Includes ------------------------------------------------------------------*/
#include "stm32f4xx_i2c.h"
#include "stm32f4xx_rcc.h"

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/

#define CR1_CLEAR_MASK    ((uint16_t)0xFBF5)      /*<! I2C registers Masks */
#define FLAG_MASK         ((uint32_t)0x00FFFFFF)  /*<! I2C FLAG mask */
#define ITEN_MASK         ((uint32_t)0x07000000)  /*<! I2C Interrupt Enable mask */

/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*/

void I2C_DeInit(I2C_TypeDef* I2Cx)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));

  if (I2Cx == I2C1)
  {
    /* Enable I2C1 reset state */
    RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1, ENABLE);
    /* Release I2C1 from reset state */
    RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1, DISABLE);    
  }
  else if (I2Cx == I2C2)
  {
    /* Enable I2C2 reset state */
    RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C2, ENABLE);
    /* Release I2C2 from reset state */
    RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C2, DISABLE);      
  }
  else 
  {
    if (I2Cx == I2C3)
    {
      /* Enable I2C3 reset state */
      RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C3, ENABLE);
      /* Release I2C3 from reset state */
      RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C3, DISABLE);     
    }
  }
}

void I2C_Init(I2C_TypeDef* I2Cx, I2C_InitTypeDef* I2C_InitStruct)
{
  uint16_t tmpreg = 0, freqrange = 0;
  uint16_t result = 0x04;
  uint32_t pclk1 = 8000000;
  RCC_ClocksTypeDef  rcc_clocks;
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_I2C_CLOCK_SPEED(I2C_InitStruct->I2C_ClockSpeed));
  assert_param(IS_I2C_MODE(I2C_InitStruct->I2C_Mode));
  assert_param(IS_I2C_DUTY_CYCLE(I2C_InitStruct->I2C_DutyCycle));
  assert_param(IS_I2C_OWN_ADDRESS1(I2C_InitStruct->I2C_OwnAddress1));
  assert_param(IS_I2C_ACK_STATE(I2C_InitStruct->I2C_Ack));
  assert_param(IS_I2C_ACKNOWLEDGE_ADDRESS(I2C_InitStruct->I2C_AcknowledgedAddress));

/*---------------------------- I2Cx CR2 Configuration ------------------------*/
  /* Get the I2Cx CR2 value */
  tmpreg = I2Cx->CR2;
  /* Clear frequency FREQ[5:0] bits */
  tmpreg &= (uint16_t)~((uint16_t)I2C_CR2_FREQ);
  /* Get pclk1 frequency value */
  RCC_GetClocksFreq(&rcc_clocks);
  pclk1 = rcc_clocks.PCLK1_Frequency;
  /* Set frequency bits depending on pclk1 value */
  freqrange = (uint16_t)(pclk1 / 1000000);
  tmpreg |= freqrange;
  /* Write to I2Cx CR2 */
  I2Cx->CR2 = tmpreg;

/*---------------------------- I2Cx CCR Configuration ------------------------*/
  /* Disable the selected I2C peripheral to configure TRISE */
  I2Cx->CR1 &= (uint16_t)~((uint16_t)I2C_CR1_PE);
  /* Reset tmpreg value */
  /* Clear F/S, DUTY and CCR[11:0] bits */
  tmpreg = 0;

  /* Configure speed in standard mode */
  if (I2C_InitStruct->I2C_ClockSpeed <= 100000)
  {
    /* Standard mode speed calculate */
    result = (uint16_t)(pclk1 / (I2C_InitStruct->I2C_ClockSpeed << 1));
    /* Test if CCR value is under 0x4*/
    if (result < 0x04)
    {
      /* Set minimum allowed value */
      result = 0x04;  
    }
    /* Set speed value for standard mode */
    tmpreg |= result;     
    /* Set Maximum Rise Time for standard mode */
    I2Cx->TRISE = freqrange + 1; 
  }
  /* Configure speed in fast mode */
  /* To use the I2C at 400 KHz (in fast mode), the PCLK1 frequency (I2C peripheral
     input clock) must be a multiple of 10 MHz */
  else /*(I2C_InitStruct->I2C_ClockSpeed <= 400000)*/
  {
    if (I2C_InitStruct->I2C_DutyCycle == I2C_DutyCycle_2)
    {
      /* Fast mode speed calculate: Tlow/Thigh = 2 */
      result = (uint16_t)(pclk1 / (I2C_InitStruct->I2C_ClockSpeed * 3));
    }
    else /*I2C_InitStruct->I2C_DutyCycle == I2C_DutyCycle_16_9*/
    {
      /* Fast mode speed calculate: Tlow/Thigh = 16/9 */
      result = (uint16_t)(pclk1 / (I2C_InitStruct->I2C_ClockSpeed * 25));
      /* Set DUTY bit */
      result |= I2C_DutyCycle_16_9;
    }

    /* Test if CCR value is under 0x1*/
    if ((result & I2C_CCR_CCR) == 0)
    {
      /* Set minimum allowed value */
      result |= (uint16_t)0x0001;  
    }
    /* Set speed value and set F/S bit for fast mode */
    tmpreg |= (uint16_t)(result | I2C_CCR_FS);
    /* Set Maximum Rise Time for fast mode */
    I2Cx->TRISE = (uint16_t)(((freqrange * (uint16_t)300) / (uint16_t)1000) + (uint16_t)1);  
  }

  /* Write to I2Cx CCR */
  I2Cx->CCR = tmpreg;
  /* Enable the selected I2C peripheral */
  I2Cx->CR1 |= I2C_CR1_PE;

/*---------------------------- I2Cx CR1 Configuration ------------------------*/
  /* Get the I2Cx CR1 value */
  tmpreg = I2Cx->CR1;
  /* Clear ACK, SMBTYPE and  SMBUS bits */
  tmpreg &= CR1_CLEAR_MASK;
  /* Configure I2Cx: mode and acknowledgement */
  /* Set SMBTYPE and SMBUS bits according to I2C_Mode value */
  /* Set ACK bit according to I2C_Ack value */
  tmpreg |= (uint16_t)((uint32_t)I2C_InitStruct->I2C_Mode | I2C_InitStruct->I2C_Ack);
  /* Write to I2Cx CR1 */
  I2Cx->CR1 = tmpreg;

/*---------------------------- I2Cx OAR1 Configuration -----------------------*/
  /* Set I2Cx Own Address1 and acknowledged address */
  I2Cx->OAR1 = (I2C_InitStruct->I2C_AcknowledgedAddress | I2C_InitStruct->I2C_OwnAddress1);
}

void I2C_StructInit(I2C_InitTypeDef* I2C_InitStruct)
{
/*---------------- Reset I2C init structure parameters values ----------------*/
  /* initialize the I2C_ClockSpeed member */
  I2C_InitStruct->I2C_ClockSpeed = 5000;
  /* Initialize the I2C_Mode member */
  I2C_InitStruct->I2C_Mode = I2C_Mode_I2C;
  /* Initialize the I2C_DutyCycle member */
  I2C_InitStruct->I2C_DutyCycle = I2C_DutyCycle_2;
  /* Initialize the I2C_OwnAddress1 member */
  I2C_InitStruct->I2C_OwnAddress1 = 0;
  /* Initialize the I2C_Ack member */
  I2C_InitStruct->I2C_Ack = I2C_Ack_Disable;
  /* Initialize the I2C_AcknowledgedAddress member */
  I2C_InitStruct->I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
}

void I2C_Cmd(I2C_TypeDef* I2Cx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {
    /* Enable the selected I2C peripheral */
    I2Cx->CR1 |= I2C_CR1_PE;
  }
  else
  {
    /* Disable the selected I2C peripheral */
    I2Cx->CR1 &= (uint16_t)~((uint16_t)I2C_CR1_PE);
  }
}

void I2C_AnalogFilterCmd(I2C_TypeDef* I2Cx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {
    /* Enable the analog filter */
    I2Cx->FLTR &= (uint16_t)~((uint16_t)I2C_FLTR_ANOFF);    
  }
  else
  {
    /* Disable the analog filter */
    I2Cx->FLTR |= I2C_FLTR_ANOFF;
  }
}

void I2C_DigitalFilterConfig(I2C_TypeDef* I2Cx, uint16_t I2C_DigitalFilter)
{
  uint16_t tmpreg = 0;
  
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_I2C_DIGITAL_FILTER(I2C_DigitalFilter));
  
  /* Get the old register value */
  tmpreg = I2Cx->FLTR;
  
  /* Reset I2Cx DNF bit [3:0] */
  tmpreg &= (uint16_t)~((uint16_t)I2C_FLTR_DNF);
  
  /* Set I2Cx DNF coefficient */
  tmpreg |= (uint16_t)((uint16_t)I2C_DigitalFilter & I2C_FLTR_DNF);
  
  /* Store the new register value */
  I2Cx->FLTR = tmpreg;
}

void I2C_GenerateSTART(I2C_TypeDef* I2Cx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {
    /* Generate a START condition */
    I2Cx->CR1 |= I2C_CR1_START;
  }
  else
  {
    /* Disable the START condition generation */
    I2Cx->CR1 &= (uint16_t)~((uint16_t)I2C_CR1_START);
  }
}

void I2C_GenerateSTOP(I2C_TypeDef* I2Cx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {
    /* Generate a STOP condition */
    I2Cx->CR1 |= I2C_CR1_STOP;
  }
  else
  {
    /* Disable the STOP condition generation */
    I2Cx->CR1 &= (uint16_t)~((uint16_t)I2C_CR1_STOP);
  }
}

void I2C_Send7bitAddress(I2C_TypeDef* I2Cx, uint8_t Address, uint8_t I2C_Direction)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_I2C_DIRECTION(I2C_Direction));
  /* Test on the direction to set/reset the read/write bit */
  if (I2C_Direction != I2C_Direction_Transmitter)
  {
    /* Set the address bit0 for read */
    Address |= I2C_OAR1_ADD0;
  }
  else
  {
    /* Reset the address bit0 for write */
    Address &= (uint8_t)~((uint8_t)I2C_OAR1_ADD0);
  }
  /* Send the address */
  I2Cx->DR = Address;
}

void I2C_AcknowledgeConfig(I2C_TypeDef* I2Cx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {
    /* Enable the acknowledgement */
    I2Cx->CR1 |= I2C_CR1_ACK;
  }
  else
  {
    /* Disable the acknowledgement */
    I2Cx->CR1 &= (uint16_t)~((uint16_t)I2C_CR1_ACK);
  }
}

void I2C_OwnAddress2Config(I2C_TypeDef* I2Cx, uint8_t Address)
{
  uint16_t tmpreg = 0;

  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));

  /* Get the old register value */
  tmpreg = I2Cx->OAR2;

  /* Reset I2Cx Own address2 bit [7:1] */
  tmpreg &= (uint16_t)~((uint16_t)I2C_OAR2_ADD2);

  /* Set I2Cx Own address2 */
  tmpreg |= (uint16_t)((uint16_t)Address & (uint16_t)0x00FE);

  /* Store the new register value */
  I2Cx->OAR2 = tmpreg;
}

void I2C_DualAddressCmd(I2C_TypeDef* I2Cx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {
    /* Enable dual addressing mode */
    I2Cx->OAR2 |= I2C_OAR2_ENDUAL;
  }
  else
  {
    /* Disable dual addressing mode */
    I2Cx->OAR2 &= (uint16_t)~((uint16_t)I2C_OAR2_ENDUAL);
  }
}

void I2C_GeneralCallCmd(I2C_TypeDef* I2Cx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {
    /* Enable generall call */
    I2Cx->CR1 |= I2C_CR1_ENGC;
  }
  else
  {
    /* Disable generall call */
    I2Cx->CR1 &= (uint16_t)~((uint16_t)I2C_CR1_ENGC);
  }
}

void I2C_SoftwareResetCmd(I2C_TypeDef* I2Cx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {
    /* Peripheral under reset */
    I2Cx->CR1 |= I2C_CR1_SWRST;
  }
  else
  {
    /* Peripheral not under reset */
    I2Cx->CR1 &= (uint16_t)~((uint16_t)I2C_CR1_SWRST);
  }
}

void I2C_StretchClockCmd(I2C_TypeDef* I2Cx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState == DISABLE)
  {
    /* Enable the selected I2C Clock stretching */
    I2Cx->CR1 |= I2C_CR1_NOSTRETCH;
  }
  else
  {
    /* Disable the selected I2C Clock stretching */
    I2Cx->CR1 &= (uint16_t)~((uint16_t)I2C_CR1_NOSTRETCH);
  }
}

void I2C_FastModeDutyCycleConfig(I2C_TypeDef* I2Cx, uint16_t I2C_DutyCycle)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_I2C_DUTY_CYCLE(I2C_DutyCycle));
  if (I2C_DutyCycle != I2C_DutyCycle_16_9)
  {
    /* I2C fast mode Tlow/Thigh=2 */
    I2Cx->CCR &= I2C_DutyCycle_2;
  }
  else
  {
    /* I2C fast mode Tlow/Thigh=16/9 */
    I2Cx->CCR |= I2C_DutyCycle_16_9;
  }
}

void I2C_NACKPositionConfig(I2C_TypeDef* I2Cx, uint16_t I2C_NACKPosition)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_I2C_NACK_POSITION(I2C_NACKPosition));
  
  /* Check the input parameter */
  if (I2C_NACKPosition == I2C_NACKPosition_Next)
  {
    /* Next byte in shift register is the last received byte */
    I2Cx->CR1 |= I2C_NACKPosition_Next;
  }
  else
  {
    /* Current byte in shift register is the last received byte */
    I2Cx->CR1 &= I2C_NACKPosition_Current;
  }
}

void I2C_SMBusAlertConfig(I2C_TypeDef* I2Cx, uint16_t I2C_SMBusAlert)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_I2C_SMBUS_ALERT(I2C_SMBusAlert));
  if (I2C_SMBusAlert == I2C_SMBusAlert_Low)
  {
    /* Drive the SMBusAlert pin Low */
    I2Cx->CR1 |= I2C_SMBusAlert_Low;
  }
  else
  {
    /* Drive the SMBusAlert pin High  */
    I2Cx->CR1 &= I2C_SMBusAlert_High;
  }
}

void I2C_ARPCmd(I2C_TypeDef* I2Cx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {
    /* Enable the selected I2C ARP */
    I2Cx->CR1 |= I2C_CR1_ENARP;
  }
  else
  {
    /* Disable the selected I2C ARP */
    I2Cx->CR1 &= (uint16_t)~((uint16_t)I2C_CR1_ENARP);
  }
}
void I2C_SendData(I2C_TypeDef* I2Cx, uint8_t Data)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  /* Write in the DR register the data to be sent */
  I2Cx->DR = Data;
}

uint8_t I2C_ReceiveData(I2C_TypeDef* I2Cx)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  /* Return the data in the DR register */
  return (uint8_t)I2Cx->DR;
}

void I2C_TransmitPEC(I2C_TypeDef* I2Cx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {
    /* Enable the selected I2C PEC transmission */
    I2Cx->CR1 |= I2C_CR1_PEC;
  }
  else
  {
    /* Disable the selected I2C PEC transmission */
    I2Cx->CR1 &= (uint16_t)~((uint16_t)I2C_CR1_PEC);
  }
}

void I2C_PECPositionConfig(I2C_TypeDef* I2Cx, uint16_t I2C_PECPosition)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_I2C_PEC_POSITION(I2C_PECPosition));
  if (I2C_PECPosition == I2C_PECPosition_Next)
  {
    /* Next byte in shift register is PEC */
    I2Cx->CR1 |= I2C_PECPosition_Next;
  }
  else
  {
    /* Current byte in shift register is PEC */
    I2Cx->CR1 &= I2C_PECPosition_Current;
  }
}

void I2C_CalculatePEC(I2C_TypeDef* I2Cx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {
    /* Enable the selected I2C PEC calculation */
    I2Cx->CR1 |= I2C_CR1_ENPEC;
  }
  else
  {
    /* Disable the selected I2C PEC calculation */
    I2Cx->CR1 &= (uint16_t)~((uint16_t)I2C_CR1_ENPEC);
  }
}

uint8_t I2C_GetPEC(I2C_TypeDef* I2Cx)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  /* Return the selected I2C PEC value */
  return ((I2Cx->SR2) >> 8);
}

void I2C_DMACmd(I2C_TypeDef* I2Cx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {
    /* Enable the selected I2C DMA requests */
    I2Cx->CR2 |= I2C_CR2_DMAEN;
  }
  else
  {
    /* Disable the selected I2C DMA requests */
    I2Cx->CR2 &= (uint16_t)~((uint16_t)I2C_CR2_DMAEN);
  }
}

void I2C_DMALastTransferCmd(I2C_TypeDef* I2Cx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {
    /* Next DMA transfer is the last transfer */
    I2Cx->CR2 |= I2C_CR2_LAST;
  }
  else
  {
    /* Next DMA transfer is not the last transfer */
    I2Cx->CR2 &= (uint16_t)~((uint16_t)I2C_CR2_LAST);
  }
}

uint16_t I2C_ReadRegister(I2C_TypeDef* I2Cx, uint8_t I2C_Register)
{
  __IO uint32_t tmp = 0;

  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_I2C_REGISTER(I2C_Register));

  tmp = (uint32_t) I2Cx;
  tmp += I2C_Register;

  /* Return the selected register value */
  return (*(__IO uint16_t *) tmp);
}

void I2C_ITConfig(I2C_TypeDef* I2Cx, uint16_t I2C_IT, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  assert_param(IS_I2C_CONFIG_IT(I2C_IT));
  
  if (NewState != DISABLE)
  {
    /* Enable the selected I2C interrupts */
    I2Cx->CR2 |= I2C_IT;
  }
  else
  {
    /* Disable the selected I2C interrupts */
    I2Cx->CR2 &= (uint16_t)~I2C_IT;
  }
}

/*
 ===============================================================================
                          1. Basic state monitoring                    
 ===============================================================================  
 */

ErrorStatus I2C_CheckEvent(I2C_TypeDef* I2Cx, uint32_t I2C_EVENT)
{
  uint32_t lastevent = 0;
  uint32_t flag1 = 0, flag2 = 0;
  ErrorStatus status = ERROR;

  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_I2C_EVENT(I2C_EVENT));

  /* Read the I2Cx status register */
  flag1 = I2Cx->SR1;
  flag2 = I2Cx->SR2;
  flag2 = flag2 << 16;

  /* Get the last event value from I2C status register */
  lastevent = (flag1 | flag2) & FLAG_MASK;

  /* Check whether the last event contains the I2C_EVENT */
  if ((lastevent & I2C_EVENT) == I2C_EVENT)
  {
    /* SUCCESS: last event is equal to I2C_EVENT */
    status = SUCCESS;
  }
  else
  {
    /* ERROR: last event is different from I2C_EVENT */
    status = ERROR;
  }
  /* Return status */
  return status;
}

/*
 ===============================================================================
                          2. Advanced state monitoring                   
 ===============================================================================  
 */

uint32_t I2C_GetLastEvent(I2C_TypeDef* I2Cx)
{
  uint32_t lastevent = 0;
  uint32_t flag1 = 0, flag2 = 0;

  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));

  /* Read the I2Cx status register */
  flag1 = I2Cx->SR1;
  flag2 = I2Cx->SR2;
  flag2 = flag2 << 16;

  /* Get the last event value from I2C status register */
  lastevent = (flag1 | flag2) & FLAG_MASK;

  /* Return status */
  return lastevent;
}

/*
 ===============================================================================
                          3. Flag-based state monitoring                   
 ===============================================================================  
 */

FlagStatus I2C_GetFlagStatus(I2C_TypeDef* I2Cx, uint32_t I2C_FLAG)
{
  FlagStatus bitstatus = RESET;
  __IO uint32_t i2creg = 0, i2cxbase = 0;

  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_I2C_GET_FLAG(I2C_FLAG));

  /* Get the I2Cx peripheral base address */
  i2cxbase = (uint32_t)I2Cx;
  
  /* Read flag register index */
  i2creg = I2C_FLAG >> 28;
  
  /* Get bit[23:0] of the flag */
  I2C_FLAG &= FLAG_MASK;
  
  if(i2creg != 0)
  {
    /* Get the I2Cx SR1 register address */
    i2cxbase += 0x14;
  }
  else
  {
    /* Flag in I2Cx SR2 Register */
    I2C_FLAG = (uint32_t)(I2C_FLAG >> 16);
    /* Get the I2Cx SR2 register address */
    i2cxbase += 0x18;
  }
  
  if(((*(__IO uint32_t *)i2cxbase) & I2C_FLAG) != (uint32_t)RESET)
  {
    /* I2C_FLAG is set */
    bitstatus = SET;
  }
  else
  {
    /* I2C_FLAG is reset */
    bitstatus = RESET;
  }
  
  /* Return the I2C_FLAG status */
  return  bitstatus;
}

void I2C_ClearFlag(I2C_TypeDef* I2Cx, uint32_t I2C_FLAG)
{
  uint32_t flagpos = 0;
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_I2C_CLEAR_FLAG(I2C_FLAG));
  /* Get the I2C flag position */
  flagpos = I2C_FLAG & FLAG_MASK;
  /* Clear the selected I2C flag */
  I2Cx->SR1 = (uint16_t)~flagpos;
}

ITStatus I2C_GetITStatus(I2C_TypeDef* I2Cx, uint32_t I2C_IT)
{
  ITStatus bitstatus = RESET;
  uint32_t enablestatus = 0;

  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_I2C_GET_IT(I2C_IT));

  /* Check if the interrupt source is enabled or not */
  enablestatus = (uint32_t)(((I2C_IT & ITEN_MASK) >> 16) & (I2Cx->CR2)) ;
  
  /* Get bit[23:0] of the flag */
  I2C_IT &= FLAG_MASK;

  /* Check the status of the specified I2C flag */
  if (((I2Cx->SR1 & I2C_IT) != (uint32_t)RESET) && enablestatus)
  {
    /* I2C_IT is set */
    bitstatus = SET;
  }
  else
  {
    /* I2C_IT is reset */
    bitstatus = RESET;
  }
  /* Return the I2C_IT status */
  return  bitstatus;
}

void I2C_ClearITPendingBit(I2C_TypeDef* I2Cx, uint32_t I2C_IT)
{
  uint32_t flagpos = 0;
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_I2C_CLEAR_IT(I2C_IT));

  /* Get the I2C flag position */
  flagpos = I2C_IT & FLAG_MASK;

  /* Clear the selected I2C flag */
  I2Cx->SR1 = (uint16_t)~flagpos;
}

/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/