原创 【CAN总线】CAN代码相关问题和注释（2）

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1. //CAN初始化
2. //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
3. //tbs2:时间段2的时间单元.范围:1~8;
4. //tbs1:时间段1的时间单元.范围:1~16;     CAN_BS1_1tq ~CAN_BS1_16tq
5. //brp :波特率分频器.范围:1~1024;(实际要加1,也就是1~1024) tq=(brp)*tpclk1
6. //注意以上参数任何一个都不能设为0,否则会乱.
7. //波特率=Fpclk1/((tsjw+tbs1+tbs2)*brp);
8. //mode:0,普通模式;1,回环模式;
9. //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);
10. //则波特率为:36M/((1+8+7)*5)=450Kbps
11. //返回值:0,初始化OK;
12. // 其他,初始化失败;
13. u8 CAN_Mode_Init(u8 tsjw,u8 tbs2,u8 tbs1,u16 brp,u8 mode)
14. {
15.  
16.     GPIO_InitTypeDef GPIO_InitStructure;
17.     CAN_InitTypeDef CAN_InitStructure;
18.      CAN_FilterInitTypeDef CAN_FilterInitStructure;
19. #if CAN_RX0_INT_ENABLE
20.        NVIC_InitTypeDef NVIC_InitStructure;
21. #endif
22.  
23.     RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);//使能PORTA时钟                                                 
24.  
25.       RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN1, ENABLE);//使能CAN1时钟    
26.  
27.     GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
28.     GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
29.     GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;    //复用推挽
30.     GPIO_Init(GPIOA, &GPIO_InitStructure);        //初始化IO
31.     
32.     
33.      //CAN单元设置
34.      CAN_InitStructure.CAN_TTCM=DISABLE;                         //非时间触发通信模式 //
35.      CAN_InitStructure.CAN_ABOM=DISABLE;                         //软件自动离线管理     //
36.       CAN_InitStructure.CAN_AWUM=DISABLE;                         //睡眠模式通过软件唤醒(清除CAN->MCR的SLEEP位)//
37.       CAN_InitStructure.CAN_NART=ENABLE;                             //禁止报文自动传送 //
38.       CAN_InitStructure.CAN_RFLM=DISABLE;                         //报文不锁定,新的覆盖旧的 //
39.       CAN_InitStructure.CAN_TXFP=DISABLE;                         //优先级由报文标识符决定 //
40.       CAN_InitStructure.CAN_Mode= mode;     //模式设置： mode:0,普通模式;1,回环模式; //
41.       //设置波特率
42.       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
43.       CAN_InitStructure.CAN_BS1=tbs1; //Tbs1=tbs1+1个时间单位CAN_BS1_1tq ~CAN_BS1_16tq
44.       CAN_InitStructure.CAN_BS2=tbs2;//Tbs2=tbs2+1个时间单位CAN_BS2_1tq ~    CAN_BS2_8tq
45.       CAN_InitStructure.CAN_Prescaler=brp; //分频系数(Fdiv)为brp+1    //
46.       CAN_Init(CAN1, &CAN_InitStructure); // 初始化CAN1
47.  
48.     CAN_FilterInitStructure.CAN_FilterNumber=0;     //过滤器0
49.      CAN_FilterInitStructure.CAN_FilterMode=CAN_FilterMode_IdMask;
50.       CAN_FilterInitStructure.CAN_FilterScale=CAN_FilterScale_32bit; //32位
51.       CAN_FilterInitStructure.CAN_FilterIdHigh=0x0000;////32位ID
52.       CAN_FilterInitStructure.CAN_FilterIdLow=0x0000;
53.       CAN_FilterInitStructure.CAN_FilterMaskIdHigh=0x0000;//32位MASK
54.       CAN_FilterInitStructure.CAN_FilterMaskIdLow=0x0000;
55.       CAN_FilterInitStructure.CAN_FilterFIFOAssignment=CAN_Filter_FIFO0;//过滤器0关联到FIFO0
56.      CAN_FilterInitStructure.CAN_FilterActivation=ENABLE; //激活过滤器0
57.  
58.       CAN_FilterInit(&CAN_FilterInitStructure);//滤波器初始化
59.     
60. #if CAN_RX0_INT_ENABLE
61.     
62.     CAN_ITConfig(CAN1,CAN_IT_FMP0,ENABLE);//FIFO0消息挂号中断允许.        
63.   
64.       NVIC_InitStructure.NVIC_IRQChannel = USB_LP_CAN1_RX0_IRQn;
65.       NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1; // 主优先级为1
66.       NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; // 次优先级为0
67.       NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
68.       NVIC_Init(&NVIC_InitStructure);
69. #endif
70.     return 0;
71.     
72. }
73.  
74. #if CAN_RX0_INT_ENABLE    //使能RX0中断
75. //中断服务函数            
76. void USB_LP_CAN1_RX0_IRQHandler(void)
77. {
78.       CanRxMsg RxMessage;
79.     int i=0;
80.     CAN_Receive(CAN1, 0, &RxMessage);
81.     for(i=0;i<8;i++)
82.     printf('rxbuf[%d]:%d\r\n',i,RxMessage.Data);
83. }
84. #endif
85.  
86.  
87. //can发送一组数据(固定格式:ID为0X12,标准帧,数据帧)    
88. //len:数据长度(最大为8)                
89. //msg:数据指针,最大为8个字节.
90. //返回值:0,成功;
91. //         其他,失败;
92. u8 Can_Send_Msg(u8* msg,u8 len)
93. {    
94.   u8 mbox;
95.   u16 i=0;
96.   CanTxMsg TxMessage;
97.   TxMessage.StdId=0x12;                     // 标准标识符为0
98.   TxMessage.ExtId=0x12;                 // 设置扩展标示符（29位）
99.   TxMessage.IDE=0;             // 使用扩展标识符
100.   TxMessage.RTR=0;         // 消息类型为数据帧，一帧8位
101.   TxMessage.DLC=len;                             // 发送两帧信息
102.   for(i=0;i;i++)<>
103.   TxMessage.Data=msg;                 // 第一帧信息
104.   mbox= CAN_Transmit(CAN1, &TxMessage);
105.   i=0;
106.   while((CAN_TransmitStatus(CAN1, mbox)==CAN_TxStatus_Failed)&&(i<0XFFF))i++;    //等待发送结束
107.   if(i>=0XFFF)return 1;
108.   return 0;        
109.  
110. }
111.  
112.  
113. //can口接收数据查询
114. //buf:数据缓存区;    
115. //返回值:0,无数据被收到;
116. //         其他,接收的数据长度;
117. u8 Can_Receive_Msg(u8 *buf)
118. {                 
119.      u32 i;
120.     CanRxMsg RxMessage;
121.     if( CAN_MessagePending(CAN1,CAN_FIFO0)==0)return 0;        //没有接收到数据,直接退出
122.     CAN_Receive(CAN1, CAN_FIFO0, &RxMessage);//读取数据    
123.     for(i=0;i<8;i++)
124.     buf=RxMessage.Data;
125.     return RxMessage.DLC;    
126. }