CAN 波特率400k以下不识别

debug · 发表于 2020-6-2 10:19:27

F103 CAN 120R电阻加和不加都不能识别

// CAN_SJW    CAN_BS2    CAN_BS1    CAN_Prescaler    CAN_CLK    BAUD
// CAN_SJW_1tq CAN_BS2_2tq CAN_BS1_3tq       6                36M       1M
// CAN_SJW_1tq CAN_BS2_3tq CAN_BS1_5tq       5                36M       800k
// CAN_SJW_1tq CAN_BS2_2tq CAN_BS1_3tq       12                36M       500k
// CAN_SJW_1tq CAN_BS2_3tq CAN_BS1_5tq       10                36M       400k

以上波特率可识别

400k以下无法识别了（按CAN波特率推荐配置）

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;

//u16 std_id =0x7e9;
//u32 ext_id =0x1800f001;
//u32 mask =0;

#if CAN_RX0_INT_ENABLE
NVIC_InitTypeDef    NVIC_InitStructure;
#endif

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO | RCC_APB2Periph_GPIOB, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN1, ENABLE);//使能CAN1时钟

/* Configure CAN pin: RX */    // PB8
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;    // 上拉输入
  GPIO_Init(GPIOB, &GPIO_InitStructure);
  /* Configure CAN pin: TX */ // PB9
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; // 复用推挽输出
  GPIO_Init(GPIOB, &GPIO_InitStructure);
  GPIO_PinRemapConfig(GPIO_Remap1_CAN1, ENABLE);
  /* CAN register init */
  CAN_DeInit(CAN1); //将外设CAN的全部寄存器重设为缺省值
  CAN_StructInit(&CAN_InitStructure);//把CAN_InitStruct中的每一个参数按缺省值填入

//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=DISABLE; //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; //屏蔽位模式
CAN_FilterInitStructure.CAN_FilterScale=CAN_FilterScale_32bit; //32位宽
CAN_FilterInitStructure.CAN_FilterIdHigh=0x0000;//((ext_id<<3) >>16) &0xffff; //32位ID
CAN_FilterInitStructure.CAN_FilterIdLow=0x0000;//(u16)(ext_id<<3) | CAN_ID_EXT;
//mask =(std_id<<18);
//mask ^=ext_id;
//mask =~mask;
//mask <<=3;
//mask |=0x02;
CAN_FilterInitStructure.CAN_FilterMaskIdHigh=0x0000;//(mask>>16)&0xffff;//32位MASK
CAN_FilterInitStructure.CAN_FilterMaskIdLow=0x0000;//mask&0xffff;
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;
}