stm32 can总线参考例程

//CAN初始化
//tsjw:重新同步跳跃时间单元.范围:1~3; CAN_SJW_1tq   CAN_SJW_2tq CAN_SJW_3tq CAN_SJW_4tq
//tbs2:时间段2的时间单元.范围:1~8;
//tbs1:时间段1的时间单元.范围:1~16;    CAN_BS1_1tq ~CAN_BS1_16tq
//brp :波特率分频器.范围:1~1024;(实际要加1,也就是1~1024) tq=(brp)*tpclk1
//注意以上参数任何一个都不能设为0,否则会乱.
//波特率=Fpclk1/((tsjw+tbs1+tbs2)*brp);
//mode:0,普通模式;1,回环模式;
//Fpclk1的时钟在初始化的时候设置为36M,如果设置CAN_Normal_Init(1,8,7,5,1);
//则波特率为:36M/((1+8+7)*5)=450Kbps
//返回值:0,初始化OK;
//    其他,初始化失败;


u8 CAN_Mode_Init(u8 tsjw,u8 tbs2,u8 tbs1,u16 brp,u8 mode)
{

      GPIO_InitTypeDef GPIO_InitStructure; 
      CAN_InitTypeDef        CAN_InitStructure;
      CAN_FilterInitTypeDef  CAN_FilterInitStructure;
#if CAN_RX0_INT_ENABLE 
    NVIC_InitTypeDef  NVIC_InitStructure;
#endif

      RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);//使能PORTA时钟                                                               

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN1, ENABLE);//使能CAN1时钟  

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //复用推挽
    GPIO_Init(GPIOA, &GPIO_InitStructure);      //初始化IO

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;//上拉输入
    GPIO_Init(GPIOA, &GPIO_InitStructure);//初始化IO

    //CAN单元设置
      CAN_InitStructure.CAN_TTCM=DISABLE;                        //非时间触发通信模式  //
      CAN_InitStructure.CAN_ABOM=DISABLE;                        //软件自动离线管理  //
    CAN_InitStructure.CAN_AWUM=DISABLE;                      //睡眠模式通过软件唤醒(清除CAN->MCR的SLEEP位)//
    CAN_InitStructure.CAN_NART=ENABLE;                          //禁止报文自动传送 //
    CAN_InitStructure.CAN_RFLM=DISABLE;                      //报文不锁定,新的覆盖旧的 // 
    CAN_InitStructure.CAN_TXFP=DISABLE;                      //优先级由报文标识符决定 //
    CAN_InitStructure.CAN_Mode= mode;            //模式设置： mode:0,普通模式;1,回环模式; //
    //设置波特率
    CAN_InitStructure.CAN_SJW=tsjw;             //重新同步跳跃宽度(Tsjw)为tsjw+1个时间单位  CAN_SJW_1tq    CAN_SJW_2tq CAN_SJW_3tq CAN_SJW_4tq
    CAN_InitStructure.CAN_BS1=tbs1; //Tbs1=tbs1+1个时间单位CAN_BS1_1tq ~CAN_BS1_16tq
    CAN_InitStructure.CAN_BS2=tbs2;//Tbs2=tbs2+1个时间单位CAN_BS2_1tq ~ CAN_BS2_8tq
    CAN_InitStructure.CAN_Prescaler=brp;            //分频系数(Fdiv)为brp+1  //
    CAN_Init(CAN1, &CAN_InitStructure);            // 初始化CAN1 

      CAN_FilterInitStructure.CAN_FilterNumber=0;     //过滤器0   
    CAN_FilterInitStructure.CAN_FilterMode=CAN_FilterMode_IdMask; 
    CAN_FilterInitStructure.CAN_FilterScale=CAN_FilterScale_32bit; //32位 
    CAN_FilterInitStructure.CAN_FilterIdHigh=0x0000;////32位ID
    CAN_FilterInitStructure.CAN_FilterIdLow=0x0000;
    CAN_FilterInitStructure.CAN_FilterMaskIdHigh=0x0000;//32位MASK
    CAN_FilterInitStructure.CAN_FilterMaskIdLow=0x0000;
    CAN_FilterInitStructure.CAN_FilterFIFOAssignment=CAN_Filter_FIFO0;//过滤器0关联到FIFO0
      CAN_FilterInitStructure.CAN_FilterActivation=ENABLE; //激活过滤器0

    CAN_FilterInit(&CAN_FilterInitStructure);//滤波器初始化
#if CAN_RX0_INT_ENABLE

      CAN_ITConfig(CAN1,CAN_IT_FMP0,ENABLE);//FIFO0消息挂号中断允许.            

    NVIC_InitStructure.NVIC_IRQChannel = USB_LP_CAN1_RX0_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;     // 主优先级为1
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;            // 次优先级为0
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
#endif
    return 0;
}   

#if CAN_RX0_INT_ENABLE  //使能RX0中断
//中断服务函数                
void USB_LP_CAN1_RX0_IRQHandler(void)
{
    CanRxMsg RxMessage;
    int i=0;
    CAN_Receive(CAN1, 0, &RxMessage);
    for(i=0;i<8;i++)
    printf("rxbuf[%d]:%d\r\n",i,RxMessage.Data[i]);
}
#endif

//can发送一组数据(固定格式:ID为0X12,标准帧,数据帧)   
//len:数据长度(最大为8)                     
//msg:数据指针,最大为8个字节.
//返回值:0,成功;
//       其他,失败;
u8 Can_Send_Msg(u8* msg,u8 len)
{   
  u8 mbox;
  u16 i=0;
  CanTxMsg TxMessage;
  TxMessage.StdId=0x12;                  // 标准标识符 
  TxMessage.ExtId=0x12;                // 设置扩展标示符 
  TxMessage.IDE=CAN_Id_Standard; // 标准帧
  TxMessage.RTR=CAN_RTR_Data;        // 数据帧
  TxMessage.DLC=len;                        // 要发送的数据长度
  for(i=0;i0;
  while((CAN_TransmitStatus(CAN1, mbox)==CAN_TxStatus_Failed)&&(i<0XFFF))i++;   //等待发送结束
  if(i>=0XFFF)return 1;
  return 0;     

}
//can口接收数据查询
//buf:数据缓存区;     
//返回值:0,无数据被收到;
//       其他,接收的数据长度;
u8 Can_Receive_Msg(u8 *buf)
{                  
    u32 i;
    CanRxMsg RxMessage;
    if( CAN_MessagePending(CAN1,CAN_FIFO0)==0)return 0;     //没有接收到数据,直接退出 
    CAN_Receive(CAN1, CAN_FIFO0, &RxMessage);//读取数据 
    for(i=0;i<8;i++)
    buf[i]=RxMessage.Data[i];  
    return RxMessage.DLC;   
}