text: /**
    ******************************************************************************
    * @file    CAN/CAN_LoopBack/Src/main.c 
    * @author  MCD Application Team
    * @brief   This example provides a description of how to set a communication 
    *          with the CAN in loopback mode.
    ******************************************************************************
    * @attention
    *
    * <h2><center>&copy; COPYRIGHT(c) 2017 STMicroelectronics</center></h2>
    *
    * Redistribution and use in source and binary forms, with or without modification,
    * are permitted provided that the following conditions are met:
    *   1. Redistributions of source code must retain the above copyright notice,
    *      this list of conditions and the following disclaimer.
    *   2. Redistributions in binary form must reproduce the above copyright notice,
    *      this list of conditions and the following disclaimer in the documentation
    *      and/or other materials provided with the distribution.
    *   3. Neither the name of STMicroelectronics nor the names of its contributors
    *      may be used to endorse or promote products derived from this software
    *      without specific prior written permission.
    *
    * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
    * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
    * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
    * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
    * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
    * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
    * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    *
    ******************************************************************************
    */
  
  /* Includes ------------------------------------------------------------------*/
  #include "main.h"
  
  /** @addtogroup STM32F4xx_HAL_Examples
    * @{
    */
  
  /** @addtogroup CAN_LoopBack
    * @{
    */
  
  /* Private typedef -----------------------------------------------------------*/
  /* Private define ------------------------------------------------------------*/
  /* Private macro -------------------------------------------------------------*/
  /* Private variables ---------------------------------------------------------*/
  CAN_HandleTypeDef     CanHandle;
  CAN_TxHeaderTypeDef   TxHeader;
  CAN_RxHeaderTypeDef   RxHeader;
  uint8_t               TxData[8];
  uint8_t               RxData[8];
  uint32_t              TxMailbox;
  
  /* Private function prototypes -----------------------------------------------*/
  static void SystemClock_Config(void);
  static void Error_Handler(void);
  static HAL_StatusTypeDef CAN_Polling(void);
  
  /* Private functions ---------------------------------------------------------*/
  
  /**
    * @brief  Main program
    * @param  None
    * @retval None
    */
  int main(void)
  {
  
    /* STM32F4xx HAL library initialization:
         - Configure the Flash prefetch, instruction and Data caches
         - Systick timer is configured by default as source of time base, but user 
           can eventually implement his proper time base source (a general purpose 
           timer for example or other time source), keeping in mind that Time base 
           duration should be kept 1ms since PPP_TIMEOUT_VALUEs are defined and 
           handled in milliseconds basis.
         - Set NVIC Group Priority to 4
         - Low Level Initialization: global MSP (MCU Support Package) initialization
       */
    HAL_Init();
  
    /* Configure the system clock to 180 MHz */
    SystemClock_Config();
    
    /* Configure LED1 and LED3 */
    BSP_LED_Init(LED1);
    BSP_LED_Init(LED3);
  
    if(CAN_Polling() == HAL_OK)
    {
      /* OK: Turn on LED1 */
      BSP_LED_On(LED1);
    }
    else
    {
      /* KO: Turn on LED3 */
      BSP_LED_On(LED3);
    }
    
    /* Infinite loop */
    while (1)
    {
    } 
  }
  
  /**
    * @brief  Configures the CAN, transmit and receive by polling
    * @param  None
    * @retval PASSED if the reception is well done, FAILED in other case
    */
  HAL_StatusTypeDef CAN_Polling(void)
  {
    CAN_FilterTypeDef  sFilterConfig;
    
    /*##-1- Configure the CAN peripheral #######################################*/
    CanHandle.Instance = CANx;
      
    CanHandle.Init.TimeTriggeredMode = DISABLE;
    CanHandle.Init.AutoBusOff = DISABLE;
    CanHandle.Init.AutoWakeUp = DISABLE;
    CanHandle.Init.AutoRetransmission = ENABLE;
    CanHandle.Init.ReceiveFifoLocked = DISABLE;
    CanHandle.Init.TransmitFifoPriority = DISABLE;
    CanHandle.Init.Mode = CAN_MODE_LOOPBACK;
    CanHandle.Init.SyncJumpWidth = CAN_SJW_1TQ;
    CanHandle.Init.TimeSeg1 = CAN_BS1_6TQ;
    CanHandle.Init.TimeSeg2 = CAN_BS2_2TQ;
    CanHandle.Init.Prescaler = 5;
    
    if(HAL_CAN_Init(&CanHandle) != HAL_OK)
    {
      /* Initialization Error */
      Error_Handler();
    }
  
    /*##-2- Configure the CAN Filter ###########################################*/
    sFilterConfig.FilterBank = 0;
    sFilterConfig.FilterMode = CAN_FILTERMODE_IDMASK;
    sFilterConfig.FilterScale = CAN_FILTERSCALE_32BIT;
    sFilterConfig.FilterIdHigh = 0x0000;
    sFilterConfig.FilterIdLow = 0x0000;
    sFilterConfig.FilterMaskIdHigh = 0x0000;
    sFilterConfig.FilterMaskIdLow = 0x0000;
    sFilterConfig.FilterFIFOAssignment = CAN_RX_FIFO0;
    sFilterConfig.FilterActivation = ENABLE;
    sFilterConfig.SlaveStartFilterBank = 14;
    
    if(HAL_CAN_ConfigFilter(&CanHandle, &sFilterConfig) != HAL_OK)
    {
      /* Filter configuration Error */
      Error_Handler();
    }
  
    /*##-3- Start the CAN peripheral ###########################################*/
    if (HAL_CAN_Start(&CanHandle) != HAL_OK)
    {
      /* Start Error */
      Error_Handler();
    }
  
    /*##-4- Start the Transmission process #####################################*/
    TxHeader.StdId = 0x11;
    TxHeader.RTR = CAN_RTR_DATA;
    TxHeader.IDE = CAN_ID_STD;
    TxHeader.DLC = 2;
    TxHeader.TransmitGlobalTime = DISABLE;
    TxData[0] = 0xCA;
    TxData[1] = 0xFE;
    
    /* Request transmission */
    if(HAL_CAN_AddTxMessage(&CanHandle, &TxHeader, TxData, &TxMailbox) != HAL_OK)
    {
      /* Transmission request Error */
      Error_Handler();
    }
    
    /* Wait transmission complete */
    while(HAL_CAN_GetTxMailboxesFreeLevel(&CanHandle) != 3) {}
  
    /*##-5- Start the Reception process ########################################*/
    if(HAL_CAN_GetRxFifoFillLevel(&CanHandle, CAN_RX_FIFO0) != 1)
    {
      /* Reception Missing */
      Error_Handler();
    }
  
    if(HAL_CAN_GetRxMessage(&CanHandle, CAN_RX_FIFO0, &RxHeader, RxData) != HAL_OK)
    {
      /* Reception Error */
      Error_Handler();
    }
  
    if((RxHeader.StdId != 0x11)                     ||
       (RxHeader.RTR != CAN_RTR_DATA)               ||
       (RxHeader.IDE != CAN_ID_STD)                 ||
       (RxHeader.DLC != 2)                          ||
       ((RxData[0]<<8 | RxData[1]) != 0xCAFE))
    {
      /* Rx message Error */
      return HAL_ERROR;
    }
  
    return HAL_OK; /* Test Passed */
  }
  
  /**
    * @brief  System Clock Configuration
    *         The system Clock is configured as follow : 
    *            System Clock source            = PLL (HSE)
    *            SYSCLK(Hz)                     = 180000000
    *            HCLK(Hz)                       = 180000000
    *            AHB Prescaler                  = 1
    *            APB1 Prescaler                 = 4
    *            APB2 Prescaler                 = 2
    *            HSE Frequency(Hz)              = 8000000
    *            PLL_M                          = 8
    *            PLL_N                          = 360
    *            PLL_P                          = 2
    *            PLL_Q                          = 7
    *            PLL_R                          = 2
    *            VDD(V)                         = 3.3
    *            Main regulator output voltage  = Scale1 mode
    *            Flash Latency(WS)              = 5
    * @param  None
    * @retval None
    */
  static void SystemClock_Config(void)
  {
    RCC_ClkInitTypeDef RCC_ClkInitStruct;
    RCC_OscInitTypeDef RCC_OscInitStruct;
    HAL_StatusTypeDef ret = HAL_OK;
  
    /* Enable Power Control clock */
    __HAL_RCC_PWR_CLK_ENABLE();
  
    /* The voltage scaling allows optimizing the power consumption when the device is 
       clocked below the maximum system frequency, to update the voltage scaling value 
       regarding system frequency refer to product datasheet.  */
    __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
  
    /* Enable HSE Oscillator and activate PLL with HSE as source */
    RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
    RCC_OscInitStruct.HSEState = RCC_HSE_ON;
    RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
    RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
    RCC_OscInitStruct.PLL.PLLM = 8;
    RCC_OscInitStruct.PLL.PLLN = 360;
    RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
    RCC_OscInitStruct.PLL.PLLQ = 7;
    RCC_OscInitStruct.PLL.PLLR = 2;
    
    ret = HAL_RCC_OscConfig(&RCC_OscInitStruct);
    if(ret != HAL_OK)
    {
      while(1) { ; }
    }
    
    /* Activate the OverDrive to reach the 180 MHz Frequency */  
    ret = HAL_PWREx_EnableOverDrive();
    if(ret != HAL_OK)
    {
      while(1) { ; }
    }
    
    /* Select PLL as system clock source and configure the HCLK, PCLK1 and PCLK2 clocks dividers */
    RCC_ClkInitStruct.ClockType = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2);
    RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
    RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
    RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;  
    RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;  
    
    ret = HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5);
    if(ret != HAL_OK)
    {
      while(1) { ; }
    }
  }
  
  
  /**
    * @brief  This function is executed in case of error occurrence.
    * @param  None
    * @retval None
    */
  static void Error_Handler(void)
  {
    /* User may add here some code to deal with this error */
    /* Make LED3 blink to indicate error */
    while (1)
    {
      BSP_LED_On(LED3);
      HAL_Delay(100);
      BSP_LED_Off(LED3);
      HAL_Delay(100);
    }
  }
  
  #ifdef  USE_FULL_ASSERT
  /**
    * @brief  Reports the name of the source file and the source line number
    *         where the assert_param error has occurred.
    * @param  file: pointer to the source file name
    * @param  line: assert_param error line source number
    * @retval None
    */
  void assert_failed(char *file, uint32_t line)
  {
    /* User can add his own implementation to report the file name and line number,
       ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
  
    /* Infinite loop */
    while (1)
    {
    }
  }
  #endif
  
  /**
    * @}
    */
  
  /**
    * @}
    */
  
  /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
  