Sine_logger/stm32_f0_4/lib/stm32f0xx_can.c

/**
  ******************************************************************************
  * @file    stm32f0xx_can.c
  * @author  MCD Application Team
  * @version V1.5.0
  * @date    05-December-2014
  * @brief   This file provides firmware functions to manage the following 
  *          functionalities of the Controller area network (CAN) peripheral and 
  *          applicable only for STM32F072 devices :           
  *           + Initialization and Configuration 
  *           + CAN Frames Transmission 
  *           + CAN Frames Reception    
  *           + Operation modes switch  
  *           + Error management          
  *           + Interrupts and flags        
  *         
  @verbatim
                               
 ===============================================================================      
                      ##### How to use this driver #####
 ===============================================================================                
    [..]
    (#) Enable the CAN controller interface clock using 
        RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN, ENABLE);      
    (#) CAN pins configuration:
        (++) Enable the clock for the CAN GPIOs using the following function:
             RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOx, ENABLE);   
        (++) Connect the involved CAN pins to AF0 using the following function 
             GPIO_PinAFConfig(GPIOx, GPIO_PinSourcex, GPIO_AF_CANx); 
        (++) Configure these CAN pins in alternate function mode by calling
             the function  GPIO_Init();
    (#) Initialise and configure the CAN using CAN_Init() and 
        CAN_FilterInit() functions.   
    (#) Transmit the desired CAN frame using CAN_Transmit() function.
    (#) Check the transmission of a CAN frame using CAN_TransmitStatus() function.
    (#) Cancel the transmission of a CAN frame using CAN_CancelTransmit() function.  
    (#) Receive a CAN frame using CAN_Recieve() function.
    (#) Release the receive FIFOs using CAN_FIFORelease() function.
    (#) Return the number of pending received frames using CAN_MessagePending() function.            
    (#) To control CAN events you can use one of the following two methods:
        (++) Check on CAN flags using the CAN_GetFlagStatus() function.  
        (++) Use CAN interrupts through the function CAN_ITConfig() at initialization 
             phase and CAN_GetITStatus() function into interrupt routines to check 
             if the event has occurred or not.
             After checking on a flag you should clear it using CAN_ClearFlag()
             function. And after checking on an interrupt event you should clear it 
             using CAN_ClearITPendingBit() function.            
                 
  @endverbatim
  *       
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; COPYRIGHT 2014 STMicroelectronics</center></h2>
  *
  * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
  * You may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
  *
  *        http://www.st.com/software_license_agreement_liberty_v2
  *
  * Unless required by applicable law or agreed to in writing, software 
  * distributed under the License is distributed on an "AS IS" BASIS, 
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
  ******************************************************************************
  */

/* Includes ------------------------------------------------------------------*/
#include "stm32f0xx_can.h"
#include "stm32f0xx_rcc.h"

/** @addtogroup STM32F0xx_StdPeriph_Driver
  * @{
  */

/** @defgroup CAN 
  * @brief CAN driver modules
  * @{
  */ 
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/

/* CAN Master Control Register bits */
#define MCR_DBF           ((uint32_t)0x00010000) /* software master reset */

/* CAN Mailbox Transmit Request */
#define TMIDxR_TXRQ       ((uint32_t)0x00000001) /* Transmit mailbox request */

/* CAN Filter Master Register bits */
#define FMR_FINIT         ((uint32_t)0x00000001) /* Filter init mode */

/* Time out for INAK bit */
#define INAK_TIMEOUT      ((uint32_t)0x00FFFFFF)
/* Time out for SLAK bit */
#define SLAK_TIMEOUT      ((uint32_t)0x00FFFFFF)

/* Flags in TSR register */
#define CAN_FLAGS_TSR     ((uint32_t)0x08000000) 
/* Flags in RF1R register */
#define CAN_FLAGS_RF1R    ((uint32_t)0x04000000) 
/* Flags in RF0R register */
#define CAN_FLAGS_RF0R    ((uint32_t)0x02000000) 
/* Flags in MSR register */
#define CAN_FLAGS_MSR     ((uint32_t)0x01000000) 
/* Flags in ESR register */
#define CAN_FLAGS_ESR     ((uint32_t)0x00F00000) 

/* Mailboxes definition */
#define CAN_TXMAILBOX_0   ((uint8_t)0x00)
#define CAN_TXMAILBOX_1   ((uint8_t)0x01)
#define CAN_TXMAILBOX_2   ((uint8_t)0x02) 

#define CAN_MODE_MASK     ((uint32_t) 0x00000003)

/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*/
static ITStatus CheckITStatus(uint32_t CAN_Reg, uint32_t It_Bit);

/** @defgroup CAN_Private_Functions
  * @{
  */

/** @defgroup CAN_Group1 Initialization and Configuration functions
 *  @brief    Initialization and Configuration functions 
 *
@verbatim    
 ===============================================================================
              ##### Initialization and Configuration functions #####
 ===============================================================================  
    [..] This section provides functions allowing to: 
         (+) Initialize the CAN peripherals : Prescaler, operating mode, the maximum 
             number of time quanta to perform resynchronization, the number of time 
             quanta in Bit Segment 1 and 2 and many other modes. 
         (+) Configure the CAN reception filter.                                      
         (+) Select the start bank filter for slave CAN.
         (+) Enable or disable the Debug Freeze mode for CAN.
         (+) Enable or disable the CAN Time Trigger Operation communication mode.
   
@endverbatim
  * @{
  */
  
/**
  * @brief  Deinitializes the CAN peripheral registers to their default reset values.
  * @param  CANx: where x can be 1 to select the CAN peripheral.
  * @retval None.
  */
void CAN_DeInit(CAN_TypeDef* CANx)
{
  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
 
  /* Enable CAN reset state */
  RCC_APB1PeriphResetCmd(RCC_APB1Periph_CAN, ENABLE);
  /* Release CAN from reset state */
  RCC_APB1PeriphResetCmd(RCC_APB1Periph_CAN, DISABLE);
}

/**
  * @brief  Initializes the CAN peripheral according to the specified
  *         parameters in the CAN_InitStruct.
  * @param  CANx: where x can be 1 to select the CAN peripheral.
  * @param  CAN_InitStruct: pointer to a CAN_InitTypeDef structure that contains
  *         the configuration information for the CAN peripheral.
  * @retval Constant indicates initialization succeed which will be 
  *         CAN_InitStatus_Failed or CAN_InitStatus_Success.
  */
uint8_t CAN_Init(CAN_TypeDef* CANx, CAN_InitTypeDef* CAN_InitStruct)
{
  uint8_t InitStatus = CAN_InitStatus_Failed;
  uint32_t wait_ack = 0x00000000;
  
  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
  assert_param(IS_FUNCTIONAL_STATE(CAN_InitStruct->CAN_TTCM));
  assert_param(IS_FUNCTIONAL_STATE(CAN_InitStruct->CAN_ABOM));
  assert_param(IS_FUNCTIONAL_STATE(CAN_InitStruct->CAN_AWUM));
  assert_param(IS_FUNCTIONAL_STATE(CAN_InitStruct->CAN_NART));
  assert_param(IS_FUNCTIONAL_STATE(CAN_InitStruct->CAN_RFLM));
  assert_param(IS_FUNCTIONAL_STATE(CAN_InitStruct->CAN_TXFP));
  assert_param(IS_CAN_MODE(CAN_InitStruct->CAN_Mode));
  assert_param(IS_CAN_SJW(CAN_InitStruct->CAN_SJW));
  assert_param(IS_CAN_BS1(CAN_InitStruct->CAN_BS1));
  assert_param(IS_CAN_BS2(CAN_InitStruct->CAN_BS2));
  assert_param(IS_CAN_PRESCALER(CAN_InitStruct->CAN_Prescaler));

  /* Exit from sleep mode */
  CANx->MCR &= (~(uint32_t)CAN_MCR_SLEEP);

  /* Request initialisation */
  CANx->MCR |= CAN_MCR_INRQ ;

  /* Wait the acknowledge */
  while (((CANx->MSR & CAN_MSR_INAK) != CAN_MSR_INAK) && (wait_ack != INAK_TIMEOUT))
  {
    wait_ack++;
  }

  /* Check acknowledge */
  if ((CANx->MSR & CAN_MSR_INAK) != CAN_MSR_INAK)
  {
    InitStatus = CAN_InitStatus_Failed;
  }
  else 
  {
    /* Set the time triggered communication mode */
    if (CAN_InitStruct->CAN_TTCM == ENABLE)
    {
      CANx->MCR |= CAN_MCR_TTCM;
    }
    else
    {
      CANx->MCR &= ~(uint32_t)CAN_MCR_TTCM;
    }

    /* Set the automatic bus-off management */
    if (CAN_InitStruct->CAN_ABOM == ENABLE)
    {
      CANx->MCR |= CAN_MCR_ABOM;
    }
    else
    {
      CANx->MCR &= ~(uint32_t)CAN_MCR_ABOM;
    }

    /* Set the automatic wake-up mode */
    if (CAN_InitStruct->CAN_AWUM == ENABLE)
    {
      CANx->MCR |= CAN_MCR_AWUM;
    }
    else
    {
      CANx->MCR &= ~(uint32_t)CAN_MCR_AWUM;
    }

    /* Set the no automatic retransmission */
    if (CAN_InitStruct->CAN_NART == ENABLE)
    {
      CANx->MCR |= CAN_MCR_NART;
    }
    else
    {
      CANx->MCR &= ~(uint32_t)CAN_MCR_NART;
    }

    /* Set the receive FIFO locked mode */
    if (CAN_InitStruct->CAN_RFLM == ENABLE)
    {
      CANx->MCR |= CAN_MCR_RFLM;
    }
    else
    {
      CANx->MCR &= ~(uint32_t)CAN_MCR_RFLM;
    }

    /* Set the transmit FIFO priority */
    if (CAN_InitStruct->CAN_TXFP == ENABLE)
    {
      CANx->MCR |= CAN_MCR_TXFP;
    }
    else
    {
      CANx->MCR &= ~(uint32_t)CAN_MCR_TXFP;
    }

    /* Set the bit timing register */
    CANx->BTR = (uint32_t)((uint32_t)CAN_InitStruct->CAN_Mode << 30) | \
                ((uint32_t)CAN_InitStruct->CAN_SJW << 24) | \
                ((uint32_t)CAN_InitStruct->CAN_BS1 << 16) | \
                ((uint32_t)CAN_InitStruct->CAN_BS2 << 20) | \
               ((uint32_t)CAN_InitStruct->CAN_Prescaler - 1);

    /* Request leave initialisation */
    CANx->MCR &= ~(uint32_t)CAN_MCR_INRQ;

   /* Wait the acknowledge */
   wait_ack = 0;

   while (((CANx->MSR & CAN_MSR_INAK) == (uint16_t)CAN_MSR_INAK) && (wait_ack != INAK_TIMEOUT))
   {
     wait_ack++;
   }

    /* ...and check acknowledged */
    if ((CANx->MSR & CAN_MSR_INAK) == CAN_MSR_INAK)
    {
      InitStatus = CAN_InitStatus_Failed;
    }
    else
    {
      InitStatus = CAN_InitStatus_Success ;
    }
  }

  /* At this step, return the status of initialization */
  return InitStatus;
}

/**
  * @brief  Configures the CAN reception filter according to the specified
  *         parameters in the CAN_FilterInitStruct.
  * @param  CAN_FilterInitStruct: pointer to a CAN_FilterInitTypeDef structure that
  *         contains the configuration information.
  * @retval None
  */
void CAN_FilterInit(CAN_FilterInitTypeDef* CAN_FilterInitStruct)
{
  uint32_t filter_number_bit_pos = 0;
  /* Check the parameters */
  assert_param(IS_CAN_FILTER_NUMBER(CAN_FilterInitStruct->CAN_FilterNumber));
  assert_param(IS_CAN_FILTER_MODE(CAN_FilterInitStruct->CAN_FilterMode));
  assert_param(IS_CAN_FILTER_SCALE(CAN_FilterInitStruct->CAN_FilterScale));
  assert_param(IS_CAN_FILTER_FIFO(CAN_FilterInitStruct->CAN_FilterFIFOAssignment));
  assert_param(IS_FUNCTIONAL_STATE(CAN_FilterInitStruct->CAN_FilterActivation));

  filter_number_bit_pos = ((uint32_t)1) << CAN_FilterInitStruct->CAN_FilterNumber;

  /* Initialisation mode for the filter */
  CAN->FMR |= FMR_FINIT;

  /* Filter Deactivation */
  CAN->FA1R &= ~(uint32_t)filter_number_bit_pos;

  /* Filter Scale */
  if (CAN_FilterInitStruct->CAN_FilterScale == CAN_FilterScale_16bit)
  {
    /* 16-bit scale for the filter */
    CAN->FS1R &= ~(uint32_t)filter_number_bit_pos;

    /* First 16-bit identifier and First 16-bit mask */
    /* Or First 16-bit identifier and Second 16-bit identifier */
    CAN->sFilterRegister[CAN_FilterInitStruct->CAN_FilterNumber].FR1 = 
       ((0x0000FFFF & (uint32_t)CAN_FilterInitStruct->CAN_FilterMaskIdLow) << 16) |
        (0x0000FFFF & (uint32_t)CAN_FilterInitStruct->CAN_FilterIdLow);

    /* Second 16-bit identifier and Second 16-bit mask */
    /* Or Third 16-bit identifier and Fourth 16-bit identifier */
    CAN->sFilterRegister[CAN_FilterInitStruct->CAN_FilterNumber].FR2 = 
       ((0x0000FFFF & (uint32_t)CAN_FilterInitStruct->CAN_FilterMaskIdHigh) << 16) |
        (0x0000FFFF & (uint32_t)CAN_FilterInitStruct->CAN_FilterIdHigh);
  }

  if (CAN_FilterInitStruct->CAN_FilterScale == CAN_FilterScale_32bit)
  {
    /* 32-bit scale for the filter */
    CAN->FS1R |= filter_number_bit_pos;
    /* 32-bit identifier or First 32-bit identifier */
    CAN->sFilterRegister[CAN_FilterInitStruct->CAN_FilterNumber].FR1 = 
       ((0x0000FFFF & (uint32_t)CAN_FilterInitStruct->CAN_FilterIdHigh) << 16) |
        (0x0000FFFF & (uint32_t)CAN_FilterInitStruct->CAN_FilterIdLow);
    /* 32-bit mask or Second 32-bit identifier */
    CAN->sFilterRegister[CAN_FilterInitStruct->CAN_FilterNumber].FR2 = 
       ((0x0000FFFF & (uint32_t)CAN_FilterInitStruct->CAN_FilterMaskIdHigh) << 16) |
        (0x0000FFFF & (uint32_t)CAN_FilterInitStruct->CAN_FilterMaskIdLow);
  }

  /* Filter Mode */
  if (CAN_FilterInitStruct->CAN_FilterMode == CAN_FilterMode_IdMask)
  {
    /*Id/Mask mode for the filter*/
    CAN->FM1R &= ~(uint32_t)filter_number_bit_pos;
  }
  else /* CAN_FilterInitStruct->CAN_FilterMode == CAN_FilterMode_IdList */
  {
    /*Identifier list mode for the filter*/
    CAN->FM1R |= (uint32_t)filter_number_bit_pos;
  }

  /* Filter FIFO assignment */
  if (CAN_FilterInitStruct->CAN_FilterFIFOAssignment == CAN_Filter_FIFO0)
  {
    /* FIFO 0 assignation for the filter */
    CAN->FFA1R &= ~(uint32_t)filter_number_bit_pos;
  }

  if (CAN_FilterInitStruct->CAN_FilterFIFOAssignment == CAN_Filter_FIFO1)
  {
    /* FIFO 1 assignation for the filter */
    CAN->FFA1R |= (uint32_t)filter_number_bit_pos;
  }
  
  /* Filter activation */
  if (CAN_FilterInitStruct->CAN_FilterActivation == ENABLE)
  {
    CAN->FA1R |= filter_number_bit_pos;
  }

  /* Leave the initialisation mode for the filter */
  CAN->FMR &= ~FMR_FINIT;
}

/**
  * @brief  Fills each CAN_InitStruct member with its default value.
  * @param  CAN_InitStruct: pointer to a CAN_InitTypeDef structure which ill be initialized.
  * @retval None
  */
void CAN_StructInit(CAN_InitTypeDef* CAN_InitStruct)
{
  /* Reset CAN init structure parameters values */
  
  /* Initialize the time triggered communication mode */
  CAN_InitStruct->CAN_TTCM = DISABLE;
  
  /* Initialize the automatic bus-off management */
  CAN_InitStruct->CAN_ABOM = DISABLE;
  
  /* Initialize the automatic wake-up mode */
  CAN_InitStruct->CAN_AWUM = DISABLE;
  
  /* Initialize the no automatic retransmission */
  CAN_InitStruct->CAN_NART = DISABLE;
  
  /* Initialize the receive FIFO locked mode */
  CAN_InitStruct->CAN_RFLM = DISABLE;
  
  /* Initialize the transmit FIFO priority */
  CAN_InitStruct->CAN_TXFP = DISABLE;
  
  /* Initialize the CAN_Mode member */
  CAN_InitStruct->CAN_Mode = CAN_Mode_Normal;
  
  /* Initialize the CAN_SJW member */
  CAN_InitStruct->CAN_SJW = CAN_SJW_1tq;
  
  /* Initialize the CAN_BS1 member */
  CAN_InitStruct->CAN_BS1 = CAN_BS1_4tq;
  
  /* Initialize the CAN_BS2 member */
  CAN_InitStruct->CAN_BS2 = CAN_BS2_3tq;
  
  /* Initialize the CAN_Prescaler member */
  CAN_InitStruct->CAN_Prescaler = 1;
}

/**
  * @brief  Select the start bank filter for slave CAN.
  * @param  CAN_BankNumber: Select the start slave bank filter from 1..27.
  * @retval None
  */
void CAN_SlaveStartBank(uint8_t CAN_BankNumber) 
{
  /* Check the parameters */
  assert_param(IS_CAN_BANKNUMBER(CAN_BankNumber));
  
  /* Enter Initialisation mode for the filter */
  CAN->FMR |= FMR_FINIT;
  
  /* Select the start slave bank */
  CAN->FMR &= (uint32_t)0xFFFFC0F1 ;
  CAN->FMR |= (uint32_t)(CAN_BankNumber)<<8;
  
  /* Leave Initialisation mode for the filter */
  CAN->FMR &= ~FMR_FINIT;
}

/**
  * @brief  Enables or disables the DBG Freeze for CAN.
  * @param  CANx: where x can be 1 or 2 to to select the CAN peripheral.
  * @param  NewState: new state of the CAN peripheral. 
  *          This parameter can be: ENABLE (CAN reception/transmission is frozen
  *          during debug. Reception FIFOs can still be accessed/controlled normally) 
  *          or DISABLE (CAN is working during debug).
  * @retval None
  */
void CAN_DBGFreeze(CAN_TypeDef* CANx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  
  if (NewState != DISABLE)
  {
    /* Enable Debug Freeze  */
    CANx->MCR |= MCR_DBF;
  }
  else
  {
    /* Disable Debug Freeze */
    CANx->MCR &= ~MCR_DBF;
  }
}

/**
  * @brief  Enables or disables the CAN Time TriggerOperation communication mode.
  * @note   DLC must be programmed as 8 in order Time Stamp (2 bytes) to be 
  *         sent over the CAN bus.  
  * @param  CANx: where x can be 1 or 2 to to select the CAN peripheral.
  * @param  NewState: Mode new state. This parameter can be: ENABLE or DISABLE.
  *         When enabled, Time stamp (TIME[15:0]) value is  sent in the last two
  *         data bytes of the 8-byte message: TIME[7:0] in data byte 6 and TIME[15:8] 
  *         in data byte 7. 
  * @retval None
  */
void CAN_TTComModeCmd(CAN_TypeDef* CANx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {
    /* Enable the TTCM mode */
    CANx->MCR |= CAN_MCR_TTCM;

    /* Set TGT bits */
    CANx->sTxMailBox[0].TDTR |= ((uint32_t)CAN_TDT0R_TGT);
    CANx->sTxMailBox[1].TDTR |= ((uint32_t)CAN_TDT1R_TGT);
    CANx->sTxMailBox[2].TDTR |= ((uint32_t)CAN_TDT2R_TGT);
  }
  else
  {
    /* Disable the TTCM mode */
    CANx->MCR &= (uint32_t)(~(uint32_t)CAN_MCR_TTCM);

    /* Reset TGT bits */
    CANx->sTxMailBox[0].TDTR &= ((uint32_t)~CAN_TDT0R_TGT);
    CANx->sTxMailBox[1].TDTR &= ((uint32_t)~CAN_TDT1R_TGT);
    CANx->sTxMailBox[2].TDTR &= ((uint32_t)~CAN_TDT2R_TGT);
  }
}
/**
  * @}
  */


/** @defgroup CAN_Group2 CAN Frames Transmission functions
 *  @brief    CAN Frames Transmission functions 
 *
@verbatim    
 ===============================================================================
                ##### CAN Frames Transmission functions #####
 ===============================================================================  
    [..] This section provides functions allowing to 
         (+) Initiate and transmit a CAN frame message (if there is an empty mailbox).
         (+) Check the transmission status of a CAN Frame.
         (+) Cancel a transmit request.
   
@endverbatim
  * @{
  */

/**
  * @brief  Initiates and transmits a CAN frame message.
  * @param  CANx: where x can be 1 or 2 to to select the CAN peripheral.
  * @param  TxMessage: pointer to a structure which contains CAN Id, CAN DLC and CAN data.
  * @retval The number of the mailbox that is used for transmission or
  *         CAN_TxStatus_NoMailBox if there is no empty mailbox.
  */
uint8_t CAN_Transmit(CAN_TypeDef* CANx, CanTxMsg* TxMessage)
{
  uint8_t transmit_mailbox = 0;
  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
  assert_param(IS_CAN_IDTYPE(TxMessage->IDE));
  assert_param(IS_CAN_RTR(TxMessage->RTR));
  assert_param(IS_CAN_DLC(TxMessage->DLC));

  /* Select one empty transmit mailbox */
  if ((CANx->TSR&CAN_TSR_TME0) == CAN_TSR_TME0)
  {
    transmit_mailbox = 0;
  }
  else if ((CANx->TSR&CAN_TSR_TME1) == CAN_TSR_TME1)
  {
    transmit_mailbox = 1;
  }
  else if ((CANx->TSR&CAN_TSR_TME2) == CAN_TSR_TME2)
  {
    transmit_mailbox = 2;
  }
  else
  {
    transmit_mailbox = CAN_TxStatus_NoMailBox;
  }

  if (transmit_mailbox != CAN_TxStatus_NoMailBox)
  {
    /* Set up the Id */
    CANx->sTxMailBox[transmit_mailbox].TIR &= TMIDxR_TXRQ;
    if (TxMessage->IDE == CAN_Id_Standard)
    {
      assert_param(IS_CAN_STDID(TxMessage->StdId));  
      CANx->sTxMailBox[transmit_mailbox].TIR |= ((TxMessage->StdId << 21) | \
                                                  TxMessage->RTR);
    }
    else
    {
      assert_param(IS_CAN_EXTID(TxMessage->ExtId));
      CANx->sTxMailBox[transmit_mailbox].TIR |= ((TxMessage->ExtId << 3) | \
                                                  TxMessage->IDE | \
                                                  TxMessage->RTR);
    }
    
    /* Set up the DLC */
    TxMessage->DLC &= (uint8_t)0x0000000F;
    CANx->sTxMailBox[transmit_mailbox].TDTR &= (uint32_t)0xFFFFFFF0;
    CANx->sTxMailBox[transmit_mailbox].TDTR |= TxMessage->DLC;

    /* Set up the data field */
    CANx->sTxMailBox[transmit_mailbox].TDLR = (((uint32_t)TxMessage->Data[3] << 24) | 
                                             ((uint32_t)TxMessage->Data[2] << 16) |
                                             ((uint32_t)TxMessage->Data[1] << 8) | 
                                             ((uint32_t)TxMessage->Data[0]));
    CANx->sTxMailBox[transmit_mailbox].TDHR = (((uint32_t)TxMessage->Data[7] << 24) | 
                                             ((uint32_t)TxMessage->Data[6] << 16) |
                                             ((uint32_t)TxMessage->Data[5] << 8) |
                                             ((uint32_t)TxMessage->Data[4]));
    /* Request transmission */
    CANx->sTxMailBox[transmit_mailbox].TIR |= TMIDxR_TXRQ;
  }
  return transmit_mailbox;
}

/**
  * @brief  Checks the transmission status of a CAN Frame.
  * @param  CANx: where x can be 1 to select the CAN peripheral.
  * @param  TransmitMailbox: the number of the mailbox that is used for transmission.
  * @retval CAN_TxStatus_Ok if the CAN driver transmits the message, 
  *         CAN_TxStatus_Failed in an other case.
  */
uint8_t CAN_TransmitStatus(CAN_TypeDef* CANx, uint8_t TransmitMailbox)
{
  uint32_t state = 0;

  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
  assert_param(IS_CAN_TRANSMITMAILBOX(TransmitMailbox));
 
  switch (TransmitMailbox)
  {
    case (CAN_TXMAILBOX_0): 
      state =   CANx->TSR &  (CAN_TSR_RQCP0 | CAN_TSR_TXOK0 | CAN_TSR_TME0);
      break;
    case (CAN_TXMAILBOX_1): 
      state =   CANx->TSR &  (CAN_TSR_RQCP1 | CAN_TSR_TXOK1 | CAN_TSR_TME1);
      break;
    case (CAN_TXMAILBOX_2): 
      state =   CANx->TSR &  (CAN_TSR_RQCP2 | CAN_TSR_TXOK2 | CAN_TSR_TME2);
      break;
    default:
      state = CAN_TxStatus_Failed;
      break;
  }
  switch (state)
  {
      /* transmit pending  */
    case (0x0): state = CAN_TxStatus_Pending;
      break;
      /* transmit failed  */
     case (CAN_TSR_RQCP0 | CAN_TSR_TME0): state = CAN_TxStatus_Failed;
      break;
     case (CAN_TSR_RQCP1 | CAN_TSR_TME1): state = CAN_TxStatus_Failed;
      break;
     case (CAN_TSR_RQCP2 | CAN_TSR_TME2): state = CAN_TxStatus_Failed;
      break;
      /* transmit succeeded  */
    case (CAN_TSR_RQCP0 | CAN_TSR_TXOK0 | CAN_TSR_TME0):state = CAN_TxStatus_Ok;
      break;
    case (CAN_TSR_RQCP1 | CAN_TSR_TXOK1 | CAN_TSR_TME1):state = CAN_TxStatus_Ok;
      break;
    case (CAN_TSR_RQCP2 | CAN_TSR_TXOK2 | CAN_TSR_TME2):state = CAN_TxStatus_Ok;
      break;
    default: state = CAN_TxStatus_Failed;
      break;
  }
  return (uint8_t) state;
}

/**
  * @brief  Cancels a transmit request.
  * @param  CANx: where x can be 1 to select the CAN peripheral.
  * @param  Mailbox: Mailbox number.
  * @retval None
  */
void CAN_CancelTransmit(CAN_TypeDef* CANx, uint8_t Mailbox)
{
  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
  assert_param(IS_CAN_TRANSMITMAILBOX(Mailbox));
  /* abort transmission */
  switch (Mailbox)
  {
    case (CAN_TXMAILBOX_0): CANx->TSR |= CAN_TSR_ABRQ0;
      break;
    case (CAN_TXMAILBOX_1): CANx->TSR |= CAN_TSR_ABRQ1;
      break;
    case (CAN_TXMAILBOX_2): CANx->TSR |= CAN_TSR_ABRQ2;
      break;
    default:
      break;
  }
}
/**
  * @}
  */


/** @defgroup CAN_Group3 CAN Frames Reception functions
 *  @brief    CAN Frames Reception functions 
 *
@verbatim    
 ===============================================================================
                  ##### CAN Frames Reception functions #####
 ===============================================================================  
    [..] This section provides functions allowing to 
         (+) Receive a correct CAN frame.
         (+) Release a specified receive FIFO (2 FIFOs are available).
         (+) Return the number of the pending received CAN frames.
   
@endverbatim
  * @{
  */

/**
  * @brief  Receives a correct CAN frame.
  * @param  CANx: where x can be 1 to select the CAN peripheral.
  * @param  FIFONumber: Receive FIFO number, CAN_FIFO0 or CAN_FIFO1.
  * @param  RxMessage: pointer to a structure receive frame which contains CAN Id,
  *         CAN DLC, CAN data and FMI number.
  * @retval None
  */
void CAN_Receive(CAN_TypeDef* CANx, uint8_t FIFONumber, CanRxMsg* RxMessage)
{
  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
  assert_param(IS_CAN_FIFO(FIFONumber));
  /* Get the Id */
  RxMessage->IDE = (uint8_t)0x04 & CANx->sFIFOMailBox[FIFONumber].RIR;
  if (RxMessage->IDE == CAN_Id_Standard)
  {
    RxMessage->StdId = (uint32_t)0x000007FF & (CANx->sFIFOMailBox[FIFONumber].RIR >> 21);
  }
  else
  {
    RxMessage->ExtId = (uint32_t)0x1FFFFFFF & (CANx->sFIFOMailBox[FIFONumber].RIR >> 3);
  }
  
  RxMessage->RTR = (uint8_t)0x02 & CANx->sFIFOMailBox[FIFONumber].RIR;
  /* Get the DLC */
  RxMessage->DLC = (uint8_t)0x0F & CANx->sFIFOMailBox[FIFONumber].RDTR;
  /* Get the FMI */
  RxMessage->FMI = (uint8_t)0xFF & (CANx->sFIFOMailBox[FIFONumber].RDTR >> 8);
  /* Get the data field */
  RxMessage->Data[0] = (uint8_t)0xFF & CANx->sFIFOMailBox[FIFONumber].RDLR;
  RxMessage->Data[1] = (uint8_t)0xFF & (CANx->sFIFOMailBox[FIFONumber].RDLR >> 8);
  RxMessage->Data[2] = (uint8_t)0xFF & (CANx->sFIFOMailBox[FIFONumber].RDLR >> 16);
  RxMessage->Data[3] = (uint8_t)0xFF & (CANx->sFIFOMailBox[FIFONumber].RDLR >> 24);
  RxMessage->Data[4] = (uint8_t)0xFF & CANx->sFIFOMailBox[FIFONumber].RDHR;
  RxMessage->Data[5] = (uint8_t)0xFF & (CANx->sFIFOMailBox[FIFONumber].RDHR >> 8);
  RxMessage->Data[6] = (uint8_t)0xFF & (CANx->sFIFOMailBox[FIFONumber].RDHR >> 16);
  RxMessage->Data[7] = (uint8_t)0xFF & (CANx->sFIFOMailBox[FIFONumber].RDHR >> 24);
  /* Release the FIFO */
  /* Release FIFO0 */
  if (FIFONumber == CAN_FIFO0)
  {
    CANx->RF0R |= CAN_RF0R_RFOM0;
  }
  /* Release FIFO1 */
  else /* FIFONumber == CAN_FIFO1 */
  {
    CANx->RF1R |= CAN_RF1R_RFOM1;
  }
}

/**
  * @brief  Releases the specified receive FIFO.
  * @param  CANx: where x can be 1 to select the CAN peripheral.
  * @param  FIFONumber: FIFO to release, CAN_FIFO0 or CAN_FIFO1.
  * @retval None
  */
void CAN_FIFORelease(CAN_TypeDef* CANx, uint8_t FIFONumber)
{
  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
  assert_param(IS_CAN_FIFO(FIFONumber));
  /* Release FIFO0 */
  if (FIFONumber == CAN_FIFO0)
  {
    CANx->RF0R |= CAN_RF0R_RFOM0;
  }
  /* Release FIFO1 */
  else /* FIFONumber == CAN_FIFO1 */
  {
    CANx->RF1R |= CAN_RF1R_RFOM1;
  }
}

/**
  * @brief  Returns the number of pending received messages.
  * @param  CANx: where x can be 1 to select the CAN peripheral.
  * @param  FIFONumber: Receive FIFO number, CAN_FIFO0 or CAN_FIFO1.
  * @retval NbMessage : which is the number of pending message.
  */
uint8_t CAN_MessagePending(CAN_TypeDef* CANx, uint8_t FIFONumber)
{
  uint8_t message_pending=0;
  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
  assert_param(IS_CAN_FIFO(FIFONumber));
  if (FIFONumber == CAN_FIFO0)
  {
    message_pending = (uint8_t)(CANx->RF0R&(uint32_t)0x03);
  }
  else if (FIFONumber == CAN_FIFO1)
  {
    message_pending = (uint8_t)(CANx->RF1R&(uint32_t)0x03);
  }
  else
  {
    message_pending = 0;
  }
  return message_pending;
}
/**
  * @}
  */


/** @defgroup CAN_Group4 CAN Operation modes functions
 *  @brief    CAN Operation modes functions 
 *
@verbatim    
 ===============================================================================
                    ##### CAN Operation modes functions #####
 ===============================================================================  
    [..] This section provides functions allowing to select the CAN Operation modes:
         (+) sleep mode.
         (+) normal mode. 
         (+) initialization mode.
   
@endverbatim
  * @{
  */
  
  
/**
  * @brief  Selects the CAN Operation mode.
  * @param  CAN_OperatingMode: CAN Operating Mode.
  *         This parameter can be one of @ref CAN_OperatingMode_TypeDef enumeration.
  * @retval status of the requested mode which can be: 
  *         - CAN_ModeStatus_Failed:  CAN failed entering the specific mode 
  *         - CAN_ModeStatus_Success: CAN Succeed entering the specific mode 
  */
uint8_t CAN_OperatingModeRequest(CAN_TypeDef* CANx, uint8_t CAN_OperatingMode)
{
  uint8_t status = CAN_ModeStatus_Failed;
  
  /* Timeout for INAK or also for SLAK bits*/
  uint32_t timeout = INAK_TIMEOUT; 

  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
  assert_param(IS_CAN_OPERATING_MODE(CAN_OperatingMode));

  if (CAN_OperatingMode == CAN_OperatingMode_Initialization)
  {
    /* Request initialisation */
    CANx->MCR = (uint32_t)((CANx->MCR & (uint32_t)(~(uint32_t)CAN_MCR_SLEEP)) | CAN_MCR_INRQ);

    /* Wait the acknowledge */
    while (((CANx->MSR & CAN_MODE_MASK) != CAN_MSR_INAK) && (timeout != 0))
    {
      timeout--;
    }
    if ((CANx->MSR & CAN_MODE_MASK) != CAN_MSR_INAK)
    {
      status = CAN_ModeStatus_Failed;
    }
    else
    {
      status = CAN_ModeStatus_Success;
    }
  }
  else  if (CAN_OperatingMode == CAN_OperatingMode_Normal)
  {
    /* Request leave initialisation and sleep mode  and enter Normal mode */
    CANx->MCR &= (uint32_t)(~(CAN_MCR_SLEEP|CAN_MCR_INRQ));

    /* Wait the acknowledge */
    while (((CANx->MSR & CAN_MODE_MASK) != 0) && (timeout!=0))
    {
      timeout--;
    }
    if ((CANx->MSR & CAN_MODE_MASK) != 0)
    {
      status = CAN_ModeStatus_Failed;
    }
    else
    {
      status = CAN_ModeStatus_Success;
    }
  }
  else  if (CAN_OperatingMode == CAN_OperatingMode_Sleep)
  {
    /* Request Sleep mode */
    CANx->MCR = (uint32_t)((CANx->MCR & (uint32_t)(~(uint32_t)CAN_MCR_INRQ)) | CAN_MCR_SLEEP);

    /* Wait the acknowledge */
    while (((CANx->MSR & CAN_MODE_MASK) != CAN_MSR_SLAK) && (timeout!=0))
    {
      timeout--;
    }
    if ((CANx->MSR & CAN_MODE_MASK) != CAN_MSR_SLAK)
    {
      status = CAN_ModeStatus_Failed;
    }
    else
    {
      status = CAN_ModeStatus_Success;
    }
  }
  else
  {
    status = CAN_ModeStatus_Failed;
  }

  return  (uint8_t) status;
}

/**
  * @brief  Enters the Sleep (low power) mode.
  * @param  CANx: where x can be 1 to select the CAN peripheral.
  * @retval CAN_Sleep_Ok if sleep entered, CAN_Sleep_Failed otherwise.
  */
uint8_t CAN_Sleep(CAN_TypeDef* CANx)
{
  uint8_t sleepstatus = CAN_Sleep_Failed;
  
  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
    
  /* Request Sleep mode */
   CANx->MCR = (((CANx->MCR) & (uint32_t)(~(uint32_t)CAN_MCR_INRQ)) | CAN_MCR_SLEEP);
   
  /* Sleep mode status */
  if ((CANx->MSR & (CAN_MSR_SLAK|CAN_MSR_INAK)) == CAN_MSR_SLAK)
  {
    /* Sleep mode not entered */
    sleepstatus =  CAN_Sleep_Ok;
  }
  /* return sleep mode status */
   return (uint8_t)sleepstatus;
}

/**
  * @brief  Wakes up the CAN peripheral from sleep mode .
  * @param  CANx: where x can be 1 to select the CAN peripheral.
  * @retval CAN_WakeUp_Ok if sleep mode left, CAN_WakeUp_Failed otherwise.
  */
uint8_t CAN_WakeUp(CAN_TypeDef* CANx)
{
  uint32_t wait_slak = SLAK_TIMEOUT;
  uint8_t wakeupstatus = CAN_WakeUp_Failed;
  
  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
    
  /* Wake up request */
  CANx->MCR &= ~(uint32_t)CAN_MCR_SLEEP;
    
  /* Sleep mode status */
  while(((CANx->MSR & CAN_MSR_SLAK) == CAN_MSR_SLAK)&&(wait_slak!=0x00))
  {
   wait_slak--;
  }
  if((CANx->MSR & CAN_MSR_SLAK) != CAN_MSR_SLAK)
  {
   /* wake up done : Sleep mode exited */
    wakeupstatus = CAN_WakeUp_Ok;
  }
  /* return wakeup status */
  return (uint8_t)wakeupstatus;
}
/**
  * @}
  */


/** @defgroup CAN_Group5 CAN Bus Error management functions
 *  @brief    CAN Bus Error management functions 
 *
@verbatim    
 ===============================================================================
                  ##### CAN Bus Error management functions #####
 ===============================================================================  
    [..] This section provides functions allowing to 
         (+) Return the CANx's last error code (LEC).
         (+) Return the CANx Receive Error Counter (REC).
         (+) Return the LSB of the 9-bit CANx Transmit Error Counter(TEC).
    [..]
         (@) If TEC is greater than 255, The CAN is in bus-off state.
         (@) If REC or TEC are greater than 96, an Error warning flag occurs.
         (@) If REC or TEC are greater than 127, an Error Passive Flag occurs.
                        
@endverbatim
  * @{
  */
  
/**
  * @brief  Returns the CANx's last error code (LEC).
  * @param  CANx: where x can be 1 to select the CAN peripheral.
  * @retval Error code: 
  *          - CAN_ERRORCODE_NoErr: No Error  
  *          - CAN_ERRORCODE_StuffErr: Stuff Error
  *          - CAN_ERRORCODE_FormErr: Form Error
  *          - CAN_ERRORCODE_ACKErr : Acknowledgment Error
  *          - CAN_ERRORCODE_BitRecessiveErr: Bit Recessive Error
  *          - CAN_ERRORCODE_BitDominantErr: Bit Dominant Error
  *          - CAN_ERRORCODE_CRCErr: CRC Error
  *          - CAN_ERRORCODE_SoftwareSetErr: Software Set Error  
  */
uint8_t CAN_GetLastErrorCode(CAN_TypeDef* CANx)
{
  uint8_t errorcode=0;
  
  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
  
  /* Get the error code*/
  errorcode = (((uint8_t)CANx->ESR) & (uint8_t)CAN_ESR_LEC);
  
  /* Return the error code*/
  return errorcode;
}

/**
  * @brief  Returns the CANx Receive Error Counter (REC).
  * @note   In case of an error during reception, this counter is incremented 
  *         by 1 or by 8 depending on the error condition as defined by the CAN 
  *         standard. After every successful reception, the counter is 
  *         decremented by 1 or reset to 120 if its value was higher than 128. 
  *         When the counter value exceeds 127, the CAN controller enters the 
  *         error passive state.  
  * @param  CANx: where x can be 1 or 2 to to select the CAN peripheral.  
  * @retval CAN Receive Error Counter. 
  */
uint8_t CAN_GetReceiveErrorCounter(CAN_TypeDef* CANx)
{
  uint8_t counter=0;
  
  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
  
  /* Get the Receive Error Counter*/
  counter = (uint8_t)((CANx->ESR & CAN_ESR_REC)>> 24);
  
  /* Return the Receive Error Counter*/
  return counter;
}


/**
  * @brief  Returns the LSB of the 9-bit CANx Transmit Error Counter(TEC).
  * @param  CANx: where x can be 1 or 2 to to select the CAN peripheral.
  * @retval LSB of the 9-bit CAN Transmit Error Counter. 
  */
uint8_t CAN_GetLSBTransmitErrorCounter(CAN_TypeDef* CANx)
{
  uint8_t counter=0;
  
  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
  
  /* Get the LSB of the 9-bit CANx Transmit Error Counter(TEC) */
  counter = (uint8_t)((CANx->ESR & CAN_ESR_TEC)>> 16);
  
  /* Return the LSB of the 9-bit CANx Transmit Error Counter(TEC) */
  return counter;
}
/**
  * @}
  */

/** @defgroup CAN_Group6 Interrupts and flags management functions
 *  @brief   Interrupts and flags management functions
 *
@verbatim   
 ===============================================================================
              ##### Interrupts and flags management functions #####
 ===============================================================================  
    [..] This section provides functions allowing to configure the CAN Interrupts 
         and to get the status and clear flags and Interrupts pending bits.
    [..] The CAN provides 14 Interrupts sources and 15 Flags:
   
  *** Flags ***
  =============
    [..] The 15 flags can be divided on 4 groups: 
         (+) Transmit Flags:
             (++) CAN_FLAG_RQCP0. 
             (++) CAN_FLAG_RQCP1. 
             (++) CAN_FLAG_RQCP2: Request completed MailBoxes 0, 1 and 2  Flags
                  Set when when the last request (transmit or abort) has 
                  been performed. 
         (+) Receive Flags:
             (++) CAN_FLAG_FMP0.
             (++) CAN_FLAG_FMP1: FIFO 0 and 1 Message Pending Flags; 
                  Set to signal that messages are pending in the receive FIFO.
                  These Flags are cleared only by hardware. 
             (++) CAN_FLAG_FF0.
             (++) CAN_FLAG_FF1: FIFO 0 and 1 Full Flags; 
                  Set when three messages are stored in the selected FIFO.                        
             (++) CAN_FLAG_FOV0.              
             (++) CAN_FLAG_FOV1: FIFO 0 and 1 Overrun Flags; 
                  Set when a new message has been received and passed the filter 
                  while the FIFO was full.         
         (+) Operating Mode Flags: 
             (++) CAN_FLAG_WKU: Wake up Flag; 
                  Set to signal that a SOF bit has been detected while the CAN 
                  hardware was in Sleep mode. 
             (++) CAN_FLAG_SLAK: Sleep acknowledge Flag;
                  Set to signal that the CAN has entered Sleep Mode. 
         (+) Error Flags:  
             (++) CAN_FLAG_EWG: Error Warning Flag;
                  Set when the warning limit has been reached (Receive Error Counter 
                  or Transmit Error Counter greater than 96). 
                  This Flag is cleared only by hardware.
             (++) CAN_FLAG_EPV: Error Passive Flag;
                  Set when the Error Passive limit has been reached (Receive Error 
                  Counter or Transmit Error Counter greater than 127).
                  This Flag is cleared only by hardware.
             (++) CAN_FLAG_BOF: Bus-Off Flag;
                  Set when CAN enters the bus-off state. The bus-off state is 
                  entered on TEC overflow, greater than 255.
                  This Flag is cleared only by hardware.
             (++) CAN_FLAG_LEC: Last error code Flag;
                  Set If a message has been transferred (reception or transmission) 
                  with error, and the error code is hold.                      
  
  *** Interrupts ***
  ==================
    [..] The 14 interrupts can be divided on 4 groups: 
         (+) Transmit interrupt:   
             (++) CAN_IT_TME: Transmit mailbox empty Interrupt;
                  If enabled, this interrupt source is pending when no transmit 
                  request are pending for Tx mailboxes.      
         (+) Receive Interrupts:   
             (++) CAN_IT_FMP0.
             (++) CAN_IT_FMP1: FIFO 0 and FIFO1 message pending Interrupts;
                  If enabled, these interrupt sources are pending when messages 
                  are pending in the receive FIFO.
                  The corresponding interrupt pending bits are cleared only by hardware.
             (++) CAN_IT_FF0.              
             (++) CAN_IT_FF1: FIFO 0 and FIFO1 full Interrupts;
                  If enabled, these interrupt sources are pending when three messages 
                  are stored in the selected FIFO.
             (++) CAN_IT_FOV0.        
             (++) CAN_IT_FOV1: FIFO 0 and FIFO1 overrun Interrupts;        
                  If enabled, these interrupt sources are pending when a new message 
                  has been received and passed the filter while the FIFO was full.
         (+) Operating Mode Interrupts:    
             (++) CAN_IT_WKU: Wake-up Interrupt;
                  If enabled, this interrupt source is pending when a SOF bit has 
                  been detected while the CAN hardware was in Sleep mode.
             (++) CAN_IT_SLK: Sleep acknowledge Interrupt:
                  If enabled, this interrupt source is pending when the CAN has 
                  entered Sleep Mode.       
         (+) Error Interrupts:     
             (++) CAN_IT_EWG: Error warning Interrupt; 
                  If enabled, this interrupt source is pending when the warning limit 
                  has been reached (Receive Error Counter or Transmit Error Counter=96). 
             (++) CAN_IT_EPV: Error passive Interrupt;        
                  If enabled, this interrupt source is pending when the Error Passive 
                  limit has been reached (Receive Error Counter or Transmit Error Counter>127).
             (++) CAN_IT_BOF: Bus-off Interrupt;
                  If enabled, this interrupt source is pending when CAN enters 
                  the bus-off state. The bus-off state is entered on TEC overflow, 
                  greater than 255.
                  This Flag is cleared only by hardware.
             (++) CAN_IT_LEC: Last error code Interrupt;        
                  If enabled, this interrupt source is pending when a message has 
                  been transferred (reception or transmission) with error and the 
                  error code is hold.
             (++) CAN_IT_ERR: Error Interrupt;
                  If enabled, this interrupt source is pending when an error condition 
                  is pending.      
    [..] Managing the CAN controller events: 
         The user should identify which mode will be used in his application to manage 
         the CAN controller events: Polling mode or Interrupt mode.
         (+) In the Polling Mode it is advised to use the following functions:
             (++) CAN_GetFlagStatus() : to check if flags events occur. 
             (++) CAN_ClearFlag()     : to clear the flags events.
         (+) In the Interrupt Mode it is advised to use the following functions:
             (++) CAN_ITConfig()       : to enable or disable the interrupt source.
             (++) CAN_GetITStatus()    : to check if Interrupt occurs.
             (++) CAN_ClearITPendingBit() : to clear the Interrupt pending Bit 
                  (corresponding Flag).
                  This function has no impact on CAN_IT_FMP0 and CAN_IT_FMP1 Interrupts 
                  pending bits since there are cleared only by hardware. 
  
@endverbatim
  * @{
  */ 
/**
  * @brief  Enables or disables the specified CANx interrupts.
  * @param  CANx: where x can be 1 or 2 to to select the CAN peripheral.
  * @param  CAN_IT: specifies the CAN interrupt sources to be enabled or disabled.
  *          This parameter can be: 
  *            @arg CAN_IT_TME: Transmit mailbox empty Interrupt 
  *            @arg CAN_IT_FMP0: FIFO 0 message pending Interrupt 
  *            @arg CAN_IT_FF0: FIFO 0 full Interrupt
  *            @arg CAN_IT_FOV0: FIFO 0 overrun Interrupt
  *            @arg CAN_IT_FMP1: FIFO 1 message pending Interrupt 
  *            @arg CAN_IT_FF1: FIFO 1 full Interrupt
  *            @arg CAN_IT_FOV1: FIFO 1 overrun Interrupt
  *            @arg CAN_IT_WKU: Wake-up Interrupt
  *            @arg CAN_IT_SLK: Sleep acknowledge Interrupt  
  *            @arg CAN_IT_EWG: Error warning Interrupt
  *            @arg CAN_IT_EPV: Error passive Interrupt
  *            @arg CAN_IT_BOF: Bus-off Interrupt  
  *            @arg CAN_IT_LEC: Last error code Interrupt
  *            @arg CAN_IT_ERR: Error Interrupt
  * @param  NewState: new state of the CAN interrupts.
  *          This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
void CAN_ITConfig(CAN_TypeDef* CANx, uint32_t CAN_IT, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
  assert_param(IS_CAN_IT(CAN_IT));
  assert_param(IS_FUNCTIONAL_STATE(NewState));

  if (NewState != DISABLE)
  {
    /* Enable the selected CANx interrupt */
    CANx->IER |= CAN_IT;
  }
  else
  {
    /* Disable the selected CANx interrupt */
    CANx->IER &= ~CAN_IT;
  }
}
/**
  * @brief  Checks whether the specified CAN flag is set or not.
  * @param  CANx: where x can be 1 or 2 to to select the CAN peripheral.
  * @param  CAN_FLAG: specifies the flag to check.
  *          This parameter can be one of the following values:
  *            @arg CAN_FLAG_RQCP0: Request MailBox0 Flag
  *            @arg CAN_FLAG_RQCP1: Request MailBox1 Flag
  *            @arg CAN_FLAG_RQCP2: Request MailBox2 Flag
  *            @arg CAN_FLAG_FMP0: FIFO 0 Message Pending Flag   
  *            @arg CAN_FLAG_FF0: FIFO 0 Full Flag       
  *            @arg CAN_FLAG_FOV0: FIFO 0 Overrun Flag 
  *            @arg CAN_FLAG_FMP1: FIFO 1 Message Pending Flag   
  *            @arg CAN_FLAG_FF1: FIFO 1 Full Flag        
  *            @arg CAN_FLAG_FOV1: FIFO 1 Overrun Flag     
  *            @arg CAN_FLAG_WKU: Wake up Flag
  *            @arg CAN_FLAG_SLAK: Sleep acknowledge Flag 
  *            @arg CAN_FLAG_EWG: Error Warning Flag
  *            @arg CAN_FLAG_EPV: Error Passive Flag  
  *            @arg CAN_FLAG_BOF: Bus-Off Flag    
  *            @arg CAN_FLAG_LEC: Last error code Flag      
  * @retval The new state of CAN_FLAG (SET or RESET).
  */
FlagStatus CAN_GetFlagStatus(CAN_TypeDef* CANx, uint32_t CAN_FLAG)
{
  FlagStatus bitstatus = RESET;
  
  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
  assert_param(IS_CAN_GET_FLAG(CAN_FLAG));
  

  if((CAN_FLAG & CAN_FLAGS_ESR) != (uint32_t)RESET)
  { 
    /* Check the status of the specified CAN flag */
    if ((CANx->ESR & (CAN_FLAG & 0x000FFFFF)) != (uint32_t)RESET)
    { 
      /* CAN_FLAG is set */
      bitstatus = SET;
    }
    else
    { 
      /* CAN_FLAG is reset */
      bitstatus = RESET;
    }
  }
  else if((CAN_FLAG & CAN_FLAGS_MSR) != (uint32_t)RESET)
  { 
    /* Check the status of the specified CAN flag */
    if ((CANx->MSR & (CAN_FLAG & 0x000FFFFF)) != (uint32_t)RESET)
    { 
      /* CAN_FLAG is set */
      bitstatus = SET;
    }
    else
    { 
      /* CAN_FLAG is reset */
      bitstatus = RESET;
    }
  }
  else if((CAN_FLAG & CAN_FLAGS_TSR) != (uint32_t)RESET)
  { 
    /* Check the status of the specified CAN flag */
    if ((CANx->TSR & (CAN_FLAG & 0x000FFFFF)) != (uint32_t)RESET)
    { 
      /* CAN_FLAG is set */
      bitstatus = SET;
    }
    else
    { 
      /* CAN_FLAG is reset */
      bitstatus = RESET;
    }
  }
  else if((CAN_FLAG & CAN_FLAGS_RF0R) != (uint32_t)RESET)
  { 
    /* Check the status of the specified CAN flag */
    if ((CANx->RF0R & (CAN_FLAG & 0x000FFFFF)) != (uint32_t)RESET)
    { 
      /* CAN_FLAG is set */
      bitstatus = SET;
    }
    else
    { 
      /* CAN_FLAG is reset */
      bitstatus = RESET;
    }
  }
  else /* If(CAN_FLAG & CAN_FLAGS_RF1R != (uint32_t)RESET) */
  { 
    /* Check the status of the specified CAN flag */
    if ((uint32_t)(CANx->RF1R & (CAN_FLAG & 0x000FFFFF)) != (uint32_t)RESET)
    { 
      /* CAN_FLAG is set */
      bitstatus = SET;
    }
    else
    { 
      /* CAN_FLAG is reset */
      bitstatus = RESET;
    }
  }
  /* Return the CAN_FLAG status */
  return  bitstatus;
}

/**
  * @brief  Clears the CAN's pending flags.
  * @param  CANx: where x can be 1 or 2 to to select the CAN peripheral.
  * @param  CAN_FLAG: specifies the flag to clear.
  *          This parameter can be one of the following values:
  *            @arg CAN_FLAG_RQCP0: Request MailBox0 Flag
  *            @arg CAN_FLAG_RQCP1: Request MailBox1 Flag
  *            @arg CAN_FLAG_RQCP2: Request MailBox2 Flag 
  *            @arg CAN_FLAG_FF0: FIFO 0 Full Flag       
  *            @arg CAN_FLAG_FOV0: FIFO 0 Overrun Flag  
  *            @arg CAN_FLAG_FF1: FIFO 1 Full Flag        
  *            @arg CAN_FLAG_FOV1: FIFO 1 Overrun Flag     
  *            @arg CAN_FLAG_WKU: Wake up Flag
  *            @arg CAN_FLAG_SLAK: Sleep acknowledge Flag    
  *            @arg CAN_FLAG_LEC: Last error code Flag        
  * @retval None
  */
void CAN_ClearFlag(CAN_TypeDef* CANx, uint32_t CAN_FLAG)
{
  uint32_t flagtmp=0;
  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
  assert_param(IS_CAN_CLEAR_FLAG(CAN_FLAG));
  
  if (CAN_FLAG == CAN_FLAG_LEC) /* ESR register */
  {
    /* Clear the selected CAN flags */
    CANx->ESR = (uint32_t)RESET;
  }
  else /* MSR or TSR or RF0R or RF1R */
  {
    flagtmp = CAN_FLAG & 0x000FFFFF;

    if ((CAN_FLAG & CAN_FLAGS_RF0R)!=(uint32_t)RESET)
    {
      /* Receive Flags */
      CANx->RF0R = (uint32_t)(flagtmp);
    }
    else if ((CAN_FLAG & CAN_FLAGS_RF1R)!=(uint32_t)RESET)
    {
      /* Receive Flags */
      CANx->RF1R = (uint32_t)(flagtmp);
    }
    else if ((CAN_FLAG & CAN_FLAGS_TSR)!=(uint32_t)RESET)
    {
      /* Transmit Flags */
      CANx->TSR = (uint32_t)(flagtmp);
    }
    else /* If((CAN_FLAG & CAN_FLAGS_MSR)!=(uint32_t)RESET) */
    {
      /* Operating mode Flags */
      CANx->MSR = (uint32_t)(flagtmp);
    }
  }
}

/**
  * @brief  Checks whether the specified CANx interrupt has occurred or not.
  * @param  CANx: where x can be 1 or 2 to to select the CAN peripheral.
  * @param  CAN_IT: specifies the CAN interrupt source to check.
  *          This parameter can be one of the following values:
  *            @arg CAN_IT_TME: Transmit mailbox empty Interrupt 
  *            @arg CAN_IT_FMP0: FIFO 0 message pending Interrupt 
  *            @arg CAN_IT_FF0: FIFO 0 full Interrupt
  *            @arg CAN_IT_FOV0: FIFO 0 overrun Interrupt
  *            @arg CAN_IT_FMP1: FIFO 1 message pending Interrupt 
  *            @arg CAN_IT_FF1: FIFO 1 full Interrupt
  *            @arg CAN_IT_FOV1: FIFO 1 overrun Interrupt
  *            @arg CAN_IT_WKU: Wake-up Interrupt
  *            @arg CAN_IT_SLK: Sleep acknowledge Interrupt  
  *            @arg CAN_IT_EWG: Error warning Interrupt
  *            @arg CAN_IT_EPV: Error passive Interrupt
  *            @arg CAN_IT_BOF: Bus-off Interrupt  
  *            @arg CAN_IT_LEC: Last error code Interrupt
  *            @arg CAN_IT_ERR: Error Interrupt
  * @retval The current state of CAN_IT (SET or RESET).
  */
ITStatus CAN_GetITStatus(CAN_TypeDef* CANx, uint32_t CAN_IT)
{
  ITStatus itstatus = RESET;
  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
  assert_param(IS_CAN_IT(CAN_IT));
  
  /* check the interrupt enable bit */
 if((CANx->IER & CAN_IT) != RESET)
 {
   /* in case the Interrupt is enabled, .... */
    switch (CAN_IT)
    {
      case CAN_IT_TME:
        /* Check CAN_TSR_RQCPx bits */
        itstatus = CheckITStatus(CANx->TSR, CAN_TSR_RQCP0|CAN_TSR_RQCP1|CAN_TSR_RQCP2);  
        break;
      case CAN_IT_FMP0:
        /* Check CAN_RF0R_FMP0 bit */
        itstatus = CheckITStatus(CANx->RF0R, CAN_RF0R_FMP0);  
        break;
      case CAN_IT_FF0:
        /* Check CAN_RF0R_FULL0 bit */
        itstatus = CheckITStatus(CANx->RF0R, CAN_RF0R_FULL0);  
        break;
      case CAN_IT_FOV0:
        /* Check CAN_RF0R_FOVR0 bit */
        itstatus = CheckITStatus(CANx->RF0R, CAN_RF0R_FOVR0);  
        break;
      case CAN_IT_FMP1:
        /* Check CAN_RF1R_FMP1 bit */
        itstatus = CheckITStatus(CANx->RF1R, CAN_RF1R_FMP1);  
        break;
      case CAN_IT_FF1:
        /* Check CAN_RF1R_FULL1 bit */
        itstatus = CheckITStatus(CANx->RF1R, CAN_RF1R_FULL1);  
        break;
      case CAN_IT_FOV1:
        /* Check CAN_RF1R_FOVR1 bit */
        itstatus = CheckITStatus(CANx->RF1R, CAN_RF1R_FOVR1);  
        break;
      case CAN_IT_WKU:
        /* Check CAN_MSR_WKUI bit */
        itstatus = CheckITStatus(CANx->MSR, CAN_MSR_WKUI);  
        break;
      case CAN_IT_SLK:
        /* Check CAN_MSR_SLAKI bit */
        itstatus = CheckITStatus(CANx->MSR, CAN_MSR_SLAKI);  
        break;
      case CAN_IT_EWG:
        /* Check CAN_ESR_EWGF bit */
        itstatus = CheckITStatus(CANx->ESR, CAN_ESR_EWGF);  
        break;
      case CAN_IT_EPV:
        /* Check CAN_ESR_EPVF bit */
        itstatus = CheckITStatus(CANx->ESR, CAN_ESR_EPVF);  
        break;
      case CAN_IT_BOF:
        /* Check CAN_ESR_BOFF bit */
        itstatus = CheckITStatus(CANx->ESR, CAN_ESR_BOFF);  
        break;
      case CAN_IT_LEC:
        /* Check CAN_ESR_LEC bit */
        itstatus = CheckITStatus(CANx->ESR, CAN_ESR_LEC);  
        break;
      case CAN_IT_ERR:
        /* Check CAN_MSR_ERRI bit */ 
        itstatus = CheckITStatus(CANx->MSR, CAN_MSR_ERRI); 
        break;
      default:
        /* in case of error, return RESET */
        itstatus = RESET;
        break;
    }
  }
  else
  {
   /* in case the Interrupt is not enabled, return RESET */
    itstatus  = RESET;
  }
  
  /* Return the CAN_IT status */
  return  itstatus;
}

/**
  * @brief  Clears the CANx's interrupt pending bits.
  * @param  CANx: where x can be 1 or 2 to to select the CAN peripheral.
  * @param  CAN_IT: specifies the interrupt pending bit to clear.
  *          This parameter can be one of the following values:
  *            @arg CAN_IT_TME: Transmit mailbox empty Interrupt
  *            @arg CAN_IT_FF0: FIFO 0 full Interrupt
  *            @arg CAN_IT_FOV0: FIFO 0 overrun Interrupt
  *            @arg CAN_IT_FF1: FIFO 1 full Interrupt
  *            @arg CAN_IT_FOV1: FIFO 1 overrun Interrupt
  *            @arg CAN_IT_WKU: Wake-up Interrupt
  *            @arg CAN_IT_SLK: Sleep acknowledge Interrupt  
  *            @arg CAN_IT_EWG: Error warning Interrupt
  *            @arg CAN_IT_EPV: Error passive Interrupt
  *            @arg CAN_IT_BOF: Bus-off Interrupt  
  *            @arg CAN_IT_LEC: Last error code Interrupt
  *            @arg CAN_IT_ERR: Error Interrupt 
  * @retval None
  */
void CAN_ClearITPendingBit(CAN_TypeDef* CANx, uint32_t CAN_IT)
{
  /* Check the parameters */
  assert_param(IS_CAN_ALL_PERIPH(CANx));
  assert_param(IS_CAN_CLEAR_IT(CAN_IT));

  switch (CAN_IT)
  {
    case CAN_IT_TME:
      /* Clear CAN_TSR_RQCPx (rc_w1)*/
      CANx->TSR = CAN_TSR_RQCP0|CAN_TSR_RQCP1|CAN_TSR_RQCP2;  
      break;
    case CAN_IT_FF0:
      /* Clear CAN_RF0R_FULL0 (rc_w1)*/
      CANx->RF0R = CAN_RF0R_FULL0; 
      break;
    case CAN_IT_FOV0:
      /* Clear CAN_RF0R_FOVR0 (rc_w1)*/
      CANx->RF0R = CAN_RF0R_FOVR0; 
      break;
    case CAN_IT_FF1:
      /* Clear CAN_RF1R_FULL1 (rc_w1)*/
      CANx->RF1R = CAN_RF1R_FULL1;  
      break;
    case CAN_IT_FOV1:
      /* Clear CAN_RF1R_FOVR1 (rc_w1)*/
      CANx->RF1R = CAN_RF1R_FOVR1; 
      break;
    case CAN_IT_WKU:
      /* Clear CAN_MSR_WKUI (rc_w1)*/
      CANx->MSR = CAN_MSR_WKUI;  
      break;
    case CAN_IT_SLK:
      /* Clear CAN_MSR_SLAKI (rc_w1)*/ 
      CANx->MSR = CAN_MSR_SLAKI;   
      break;
    case CAN_IT_EWG:
      /* Clear CAN_MSR_ERRI (rc_w1) */
      CANx->MSR = CAN_MSR_ERRI;
       /* @note the corresponding Flag is cleared by hardware depending on the CAN Bus status*/ 
      break;
    case CAN_IT_EPV:
      /* Clear CAN_MSR_ERRI (rc_w1) */
      CANx->MSR = CAN_MSR_ERRI; 
       /* @note the corresponding Flag is cleared by hardware depending on the CAN Bus status*/
      break;
    case CAN_IT_BOF:
      /* Clear CAN_MSR_ERRI (rc_w1) */ 
      CANx->MSR = CAN_MSR_ERRI; 
       /* @note the corresponding Flag is cleared by hardware depending on the CAN Bus status*/
       break;
    case CAN_IT_LEC:
      /*  Clear LEC bits */
      CANx->ESR = RESET; 
      /* Clear CAN_MSR_ERRI (rc_w1) */
      CANx->MSR = CAN_MSR_ERRI; 
      break;
    case CAN_IT_ERR:
      /*Clear LEC bits */
      CANx->ESR = RESET; 
      /* Clear CAN_MSR_ERRI (rc_w1) */
      CANx->MSR = CAN_MSR_ERRI; 
       /* @note BOFF, EPVF and EWGF Flags are cleared by hardware depending on the CAN Bus status*/
       break;
    default:
       break;
   }
}
 /**
  * @}
  */

/**
  * @brief  Checks whether the CAN interrupt has occurred or not.
  * @param  CAN_Reg: specifies the CAN interrupt register to check.
  * @param  It_Bit: specifies the interrupt source bit to check.
  * @retval The new state of the CAN Interrupt (SET or RESET).
  */
static ITStatus CheckITStatus(uint32_t CAN_Reg, uint32_t It_Bit)
{
  ITStatus pendingbitstatus = RESET;
  
  if ((CAN_Reg & It_Bit) != (uint32_t)RESET)
  {
    /* CAN_IT is set */
    pendingbitstatus = SET;
  }
  else
  {
    /* CAN_IT is reset */
    pendingbitstatus = RESET;
  }
  return pendingbitstatus;
}

/**
  * @}
  */

/**
  * @}
  */

/**
  * @}
  */

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