STM32F107VCT6   TJA1021接到串口4
实现LIN的主模式
目前功能仍然没有调试通过，希望有相关经验的能指导一下。

[mw_shl_code=c,true]static void lin_gpio_init(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC | RCC_APB2Periph_GPIOD, ENABLE);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitGPIOC&GPIO_InitStructure);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  GPIO_InitGPIOC&GPIO_InitStructure);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
  GPIO_Init(GPIOD, &GPIO_InitStructure);
  GPIO_SetBits(GPIOD,GPIO_Pin_2);  
}

static void lin_nvic_init(void)
{
  NVIC_InitTypeDef NVIC_InitStructure;

  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);

  NVIC_InitStructure.NVIC_IRQChannel = UART4_IRQ;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}

static void lin_uart_init(void)
{
  USART_InitTypeDef USART_InitStructure;

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_UART4, ENABLE);
  USART_InitStructure.USART_BaudRate = 19200;
  USART_InitStructure.USART_WordLength = USART_WordLength_8b;
  USART_InitStructure.USART_StopBits = USART_StopBits_1;
  USART_InitStructure.USART_Parity = USART_Parity_No ;
  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
  USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
  USART_Init(macUSARTx, &USART_InitStructure);

  USART_LINBreakDetectLengthConfig(macUSARTx, USART_LINBreakDetectLength_11b);

  USART_LINCmd（UART4，ENABLE);
  USART_ITConfig(UART4, USART_IT_LBD, ENABLE);
  //USART_ITConfig(UART4, USART_IT_RXNE, ENABLE);
  USART_Cmd(UART4, ENABLE);
}

void LINInit(void)
{
  lin_gpio_init();
  lin_nvic_init();
  lin_uart_init();
}

void Usart_SendByte( USART_TypeDef * pUSARTx, uint8_t ch )
{
  /* 发送一个字节数据到USART1 */
  USART_SendData(pUSARTx, ch);

  /* 等待发送完毕 */
  while (USART_GetFlagStatus(pUSARTx, USART_FLAG_TXE) == RESET);
}

static unsigned char LINCalcParity(unsigned char id)
{
  unsigned char parity, p0, p1;
  parity = id;
  p0 = (BIT(parity, 0)^BIT(parity, 1)^BIT(parity, 2)^BIT(parity, 4)) << 6; //偶校验位
  p1 = (!(BIT(parity, 1)^BIT(parity, 3)^BIT(parity, 4)^BIT(parity, 5))) << 7; //奇校验位
  parity |= (p0 | p1);
  return parity;
}

/*************************************************************/
/*                       计算和校验位                        */
/*************************************************************/
static unsigned char LINCalcChecksum(unsigned char *data)
{
  unsigned int sum = 0;
  unsigned char i;

  for(i = 0; i < 8; i++)
  {
    sum += data;
    if(sum & 0xFF00)
    {
      sum = (sum & 0x00FF) + 1;
    }
  }
  sum ^= 0x00FF;
  return (unsigned char)sum;
}

#if 0
  msg_send.identifier = 0x30;
  msg_send.data[0] = 'F';
  msg_send.data[1] = 'R';
  msg_send.data[2] = 'E';
  msg_send.data[3] = 'E';
  msg_send.data[4] = 'F';
  msg_send.data[5] = 'L';
  msg_send.data[6] = 'Y';
  msg_send.data[7] = '!';
#endif
void LINSendTest(void)
{
  unsigned char check_sum, parity_id, i;

  USART_SendBreak(UART4);
  Usart_SendByte(UART4, 0x55);
  
  parity_id = LINCalcParity(msg_send.identifier);

  LINSendChar(parity_id);

  for(i = 0; i < 8; i++)
  {
    if(!LINSendChar(msg_send.data))
    {
      return(FALSE);
    }
  }

  check_sum = LINCalcChecksum(msg_send.data);
  // 发送校验和场
  LINSendChar(check_sum);

}[/mw_shl_code]