stm32l1xx_i2c.c

STM32+Grlib

  return ((I2Cx->SR2) >> 8);
}

/**
  * @}
  */

/** @defgroup I2C_Group4 DMA transfers management functions
 *  @brief   DMA transfers management functions 
 *
@verbatim   
 ===============================================================================
                         DMA transfers management functions
 ===============================================================================  
  This section provides functions allowing to configure the I2C DMA channels 
  requests.
  
@endverbatim
  * @{
  */

/**
  * @brief  Enables or disables the specified I2C DMA requests.
  * @param  I2Cx: where x can be 1 or 2 to select the I2C peripheral.
  * @param  NewState: new state of the I2C DMA transfer.
  *   This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
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);
  }
}

/**
  * @brief  Specifies that the next DMA transfer is the last one.
  * @param  I2Cx: where x can be 1 or 2 to select the I2C peripheral.
  * @param  NewState: new state of the I2C DMA last transfer.
  *   This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
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);
  }
}

/**
  * @}
  */

/** @defgroup I2C_Group5 Interrupts events and flags management functions
 *  @brief   Interrupts, events and flags management functions
 *
@verbatim   
 ===============================================================================
                Interrupts, events and flags management functions
 ===============================================================================  
  This section provides functions allowing to configure the I2C Interrupts 
  sources and check or clear the flags or pending bits status.
  The user should identify which mode will be used in his application to manage 
  the communication: Polling mode, Interrupt mode or DMA mode. 

 ===============================================================================
                          I2C State Monitoring Functions                    
 ===============================================================================   
  This I2C driver provides three different ways for I2C state monitoring
  depending on the application requirements and constraints:
         
   
     1. Basic state monitoring (Using I2C_CheckEvent() function)
     -----------------------------------------------------------
        It compares the status registers (SR1 and SR2) content to a given event
        (can be the combination of one or more flags).
        It returns SUCCESS if the current status includes the given flags 
        and returns ERROR if one or more flags are missing in the current status.

          - When to use
             - This function is suitable for most applications as well as for startup 
               activity since the events are fully described in the product reference 
               manual (RM0038).
             - It is also suitable for users who need to define their own events.

          - Limitations
             - If an error occurs (ie. error flags are set besides to the monitored 
               flags), the I2C_CheckEvent() function may return SUCCESS despite 
               the communication hold or corrupted real state. 
               In this case, it is advised to use error interrupts to monitor 
               the error events and handle them in the interrupt IRQ handler.
         
     @note 
         For error management, it is advised to use the following functions:
           - I2C_ITConfig() to configure and enable the error interrupts (I2C_IT_ERR).
           - I2Cx_ER_IRQHandler() which is called when the error interrupt occurs.
             Where x is the peripheral instance (I2C1, I2C2 ...)
           - I2C_GetFlagStatus() or I2C_GetITStatus()  to be called into the 
             I2Cx_ER_IRQHandler() function in order to determine which error occurred.
           - I2C_ClearFlag() or I2C_ClearITPendingBit() and/or I2C_SoftwareResetCmd() 
             and/or I2C_GenerateStop() in order to clear the error flag and source 
             and return to correct  communication status.
             
 
     2. Advanced state monitoring (Using the function I2C_GetLastEvent())
     -------------------------------------------------------------------- 
        Using the function I2C_GetLastEvent() which returns the image of both status 
        registers in a single word (uint32_t) (Status Register 2 value is shifted left 
        by 16 bits and concatenated to Status Register 1).

          - When to use
             - This function is suitable for the same applications above but it 
               allows to overcome the mentioned limitation of I2C_GetFlagStatus() 
               function.
             - The returned value could be compared to events already defined in 
               the library (stm32l1xx_i2c.h) or to custom values defined by user.
               This function is suitable when multiple flags are monitored at the 
               same time.
             - At the opposite of I2C_CheckEvent() function, this function allows 
               user to choose when an event is accepted (when all events flags are 
               set and no other flags are set or just when the needed flags are set 
               like I2C_CheckEvent() function.

          - Limitations
             - User may need to define his own events.
             - Same remark concerning the error management is applicable for this 
               function if user decides to check only regular communication flags 
               (and ignores error flags).
      
 
     3. Flag-based state monitoring (Using the function I2C_GetFlagStatus())
     -----------------------------------------------------------------------
     
      Using the function I2C_GetFlagStatus() which simply returns the status of 
      one single flag (ie. I2C_FLAG_RXNE ...). 

          - When to use
             - This function could be used for specific applications or in debug 
               phase.
             - It is suitable when only one flag checking is needed (most I2C 
               events are monitored through multiple flags).
          - Limitations: 
             - When calling this function, the Status register is accessed. 
               Some flags are cleared when the status register is accessed. 
               So checking the status of one Flag, may clear other ones.
             - Function may need to be called twice or more in order to monitor 
               one single event.
 
   For detailed description of Events, please refer to section I2C_Events in 
   stm32l1xx_i2c.h file.
       
@endverbatim
  * @{
  */
   
/**
  * @brief  Reads the specified I2C register and returns its value.
  * @param  I2C_Register: specifies the register to read.
  *   This parameter can be one of the following values:
  *     @arg I2C_Register_CR1:  CR1 register.
  *     @arg I2C_Register_CR2:   CR2 register.
  *     @arg I2C_Register_OAR1:  OAR1 register.
  *     @arg I2C_Register_OAR2:  OAR2 register.
  *     @arg I2C_Register_DR:    DR register.
  *     @arg I2C_Register_SR1:   SR1 register.
  *     @arg I2C_Register_SR2:   SR2 register.
  *     @arg I2C_Register_CCR:   CCR register.
  *     @arg I2C_Register_TRISE: TRISE register.
  * @retval The value of the read register.
  */
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);
}

/**
  * @brief  Enables or disables the specified I2C interrupts.
  * @param  I2Cx: where x can be 1 or 2 to select the I2C peripheral.
  * @param  I2C_IT: specifies the I2C interrupts sources to be enabled or disabled. 
  *   This parameter can be any combination of the following values:
  *     @arg I2C_IT_BUF: Buffer interrupt mask
  *     @arg I2C_IT_EVT: Event interrupt mask
  *     @arg I2C_IT_ERR: Error interrupt mask
  * @param  NewState: new state of the specified I2C interrupts.
  *   This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
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                    
 ===============================================================================  
 */

/**
  * @brief  Checks whether the last I2Cx Event is equal to the one passed
  *   as parameter.
  * @param  I2Cx: where x can be 1 or 2 to select the I2C peripheral.
  * @param  I2C_EVENT: specifies the event to be checked. 
  *   This parameter can be one of the following values:
  *     @arg I2C_EVENT_SLAVE_TRANSMITTER_ADDRESS_MATCHED           : EV1
  *     @arg I2C_EVENT_SLAVE_RECEIVER_ADDRESS_MATCHED              : EV1
  *     @arg I2C_EVENT_SLAVE_TRANSMITTER_SECONDADDRESS_MATCHED     : EV1
  *     @arg I2C_EVENT_SLAVE_RECEIVER_SECONDADDRESS_MATCHED        : EV1
  *     @arg I2C_EVENT_SLAVE_GENERALCALLADDRESS_MATCHED            : EV1
  *     @arg I2C_EVENT_SLAVE_BYTE_RECEIVED                         : EV2
  *     @arg (I2C_EVENT_SLAVE_BYTE_RECEIVED | I2C_FLAG_DUALF)      : EV2
  *     @arg (I2C_EVENT_SLAVE_BYTE_RECEIVED | I2C_FLAG_GENCALL)    : EV2
  *     @arg I2C_EVENT_SLAVE_BYTE_TRANSMITTED                      : EV3
  *     @arg (I2C_EVENT_SLAVE_BYTE_TRANSMITTED | I2C_FLAG_DUALF)   : EV3
  *     @arg (I2C_EVENT_SLAVE_BYTE_TRANSMITTED | I2C_FLAG_GENCALL) : EV3
  *     @arg I2C_EVENT_SLAVE_ACK_FAILURE                           : EV3_2
  *     @arg I2C_EVENT_SLAVE_STOP_DETECTED                         : EV4
  *     @arg I2C_EVENT_MASTER_MODE_SELECT                          : EV5
  *     @arg I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED            : EV6     
  *     @arg I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED               : EV6
  *     @arg I2C_EVENT_MASTER_BYTE_RECEIVED                        : EV7
  *     @arg I2C_EVENT_MASTER_BYTE_TRANSMITTING                    : EV8
  *     @arg I2C_EVENT_MASTER_BYTE_TRANSMITTED                     : EV8_2
  *     @arg I2C_EVENT_MASTER_MODE_ADDRESS10                       : EV9
  *     
  * @note: For detailed description of Events, please refer to section 
  *    I2C_Events in stm32l1xx_i2c.h file.
  *    
  * @retval An ErrorStatus enumeration value:
  * - SUCCESS: Last event is equal to the I2C_EVENT
  * - ERROR: Last event is different from the I2C_EVENT
  */
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                   
 ===============================================================================  
 */

/**
  * @brief  Returns the last I2Cx Event.
  * @param  I2Cx: where x can be 1 or 2 to select the I2C peripheral.
  *     
  * @note: For detailed description of Events, please refer to section 
  *    I2C_Events in stm32l1xx_i2c.h file.
  *    
  * @retval The last event
  */
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                   
 ===============================================================================  
 */

/**
  * @brief  Checks whether the specified I2C flag is set or not.
  * @param  I2Cx: where x can be 1 or 2 to select the I2C peripheral.
  * @param  I2C_FLAG: specifies the flag to check. 
  *   This parameter can be one of the following values:
  *     @arg I2C_FLAG_DUALF: Dual flag (Slave mode)
  *     @arg I2C_FLAG_SMBHOST: SMBus host header (Slave mode)
  *     @arg I2C_FLAG_SMBDEFAULT: SMBus default header (Slave mode)
  *     @arg I2C_FLAG_GENCALL: General call header flag (Slave mode)
  *     @arg I2C_FLAG_TRA: Transmitter/Receiver flag
  *     @arg I2C_FLAG_BUSY: Bus busy flag
  *     @arg I2C_FLAG_MSL: Master/Slave flag
  *     @arg I2C_FLAG_SMBALERT: SMBus Alert flag
  *     @arg I2C_FLAG_TIMEOUT: Timeout or Tlow error flag
  *     @arg I2C_FLAG_PECERR: PEC error in reception flag
  *     @arg I2C_FLAG_OVR: Overrun/Underrun flag (Slave mode)
  *     @arg I2C_FLAG_AF: Acknowledge failure flag
  *     @arg I2C_FLAG_ARLO: Arbitration lost flag (Master mode)
  *     @arg I2C_FLAG_BERR: Bus error flag
  *     @arg I2C_FLAG_TXE: Data register empty flag (Transmitter)
  *     @arg I2C_FLAG_RXNE: Data register not empty (Receiver) flag
  *     @arg I2C_FLAG_STOPF: Stop detection flag (Slave mode)
  *     @arg I2C_FLAG_ADD10: 10-bit header sent flag (Master mode)
  *     @arg I2C_FLAG_BTF: Byte transfer finished flag
  *     @arg I2C_FLAG_ADDR: Address sent flag (Master mode) 揂DSL