初学STM32 CAN通信（三）

1. stm32 CAN通信标准库函数

//CAN通信初始化函数
uint8_t CAN_Init(CAN_TypeDef* CANx, CAN_InitTypeDef* CAN_InitStruct);
//筛选器初始化函数
void CAN_FilterInit(CAN_FilterInitTypeDef* CAN_FilterInitStruct);
//发送信息函数
uint8_t CAN_Transmit(CAN_TypeDef* CANx, CanTxMsg* TxMessage);
//发送信息状态函数
uint8_t CAN_TransmitStatus(CAN_TypeDef* CANx, uint8_t TransmitMailbox);
//接收信息函数
void CAN_Receive(CAN_TypeDef* CANx, uint8_t FIFONumber, CanRxMsg* RxMessage);
//CAN通信中断使能函数
void CAN_ITConfig(CAN_TypeDef* CANx, uint32_t CAN_IT, FunctionalState NewState);
//状态有关的函数
FlagStatus CAN_GetFlagStatus(CAN_TypeDef* CANx, uint32_t CAN_FLAG);
void CAN_ClearFlag(CAN_TypeDef* CANx, uint32_t CAN_FLAG);
ITStatus CAN_GetITStatus(CAN_TypeDef* CANx, uint32_t CAN_IT);
void CAN_ClearITPendingBit(CAN_TypeDef* CANx, uint32_t CAN_IT);

2. 利用标准库进行初始化

/*
	CAN_TX:PB_13
	CAN_RX:PB_12
*/
void CAN_Config(void)
{
	//定义初始化所需结构体变量
	CAN_InitTypeDef CAN_InitStruct;
	GPIO_InitTypeDef GPIO_InitStruct;
	NVIC_InitTypeDef NVIC_InitStruct;
	//开启所用的时钟
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN2,ENABLE);
	RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB,ENABLE);
	//引脚复用
	GPIO_PinAFConfig(GPIOB,GPIO_Pin_13,GPIO_AF_CAN2);
	GPIO_PinAFConfig(GPIOB,GPIO_Pin_12,GPIO_AF_CAN2);
	//GPIO初始化
	GPIO_InitStruct.GPIO_Mode=GPIO_Mode_AF;//复用模式
	GPIO_InitStruct.GPIO_OType=GPIO_OType_PP;//推挽输出
	GPIO_InitStruct.GPIO_Pin=GPIO_Pin_13;
	GPIO_InitStruct.GPIO_PuPd=GPIO_PuPd_UP;//默认上拉
	GPIO_InitStruct.GPIO_Speed=GPIO_Speed_50MHz;//输出速率
	GPIO_Init(GPIOB,&GPIO_InitStruct);

	GPIO_InitStruct.GPIO_Mode=GPIO_Mode_AF;
	GPIO_InitStruct.GPIO_Pin=GPIO_Pin_12;
	GPIO_InitStruct.GPIO_PuPd=GPIO_PuPd_UP;
	GPIO_InitStruct.GPIO_Speed=GPIO_Speed_50MHz;
	GPIO_Init(GPIOB,&GPIO_InitStruct);
	//CAN初始化
	CAN_InitStruct.CAN_ABOM=ENABLE;//是否使能ABOM自动离线管理功能
	CAN_InitStruct.CAN_AWUM=ENABLE;//是否使能AWUM自动唤醒功能
	CAN_InitStruct.CAN_NART=ENABLE;//是否使能NART自动重传功能
	CAN_InitStruct.CAN_RFLM=DISABLE;//是否使能RFLM锁定功能
	CAN_InitStruct.CAN_TTCM=DISABLE;//是否使能TTCM时间触发功能
	CAN_InitStruct.CAN_TXFP=DISABLE;//配置TXFP报文优先级的判定方法
	CAN_InitStruct.CAN_Mode=CAN_Mode_LoopBack;//回环模式
	CAN_InitStruct.CAN_Prescaler=6;//配置CAN外设的时钟分频,可设置1-1024
	CAN_InitStruct.CAN_SJW=CAN_SJW_2tq;//配置SJW极限值
	CAN_InitStruct.CAN_BS1=CAN_BS1_4tq;//配置BS1段长度
	CAN_InitStruct.CAN_BS2=CAN_BS2_2tq;//配置BS2段长度
	CAN_Init(CAN2,&CAN_InitStruct);
	//开启中断使能
	CAN_ITConfig(CAN2,CAN_IT_FMP0,ENABLE);
	//配置中断向量
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
	NVIC_InitStruct.NVIC_IRQChannel=CAN2_RX0_IRQn;
	NVIC_InitStruct.NVIC_IRQChannelCmd=ENABLE;
	NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority=2;
	NVIC_InitStruct.NVIC_IRQChannelSubPriority=2;
	NVIC_Init(&NVIC_InitStruct);

}

3. 筛选器初始化

void CAN_Filter(void)
{
	CAN_FilterInitTypeDef CAN_FilterInitStruct;

	CAN_FilterInitStruct.CAN_FilterNumber=14;//筛选器编号
	CAN_FilterInitStruct.CAN_FilterScale=CAN_FilterScale_32bit;//设置筛选器的尺度
	CAN_FilterInitStruct.CAN_FilterMode=CAN_FilterMode_IdMask;//掩码模式
	CAN_FilterInitStruct.CAN_FilterFIFOAssignment=CAN_Filter_FIFO0;//设置经过筛选后数据存储到那个接收器
	CAN_FilterInitStruct.CAN_FilterActivation=ENABLE;//是否使能筛选器

	CAN_FilterInitStruct.CAN_FilterIdHigh=					  (((uint32_t)0x1314<<3|CAN_Id_Extended|CAN_RTR_Data)&0xFFFF0000);//CAN_FxR1寄存器的高16位
	CAN_FilterInitStruct.CAN_FilterIdLow=(((uint32_t)0x1314<<3|CAN_Id_Extended|CAN_RTR_Data)&0x0000FFFF);//CAN_FxR1寄存器的低16位
	CAN_FilterInitStruct.CAN_FilterMaskIdHigh=0xFFFF;CAN_FxR2寄存器的高16位
	CAN_FilterInitStruct.CAN_FilterMaskIdLow=0xFFFF;CAN_FxR2寄存器的低16位

	CAN_FilterInit(&CAN_FilterInitStruct);
}

4. 发送数据

uint8_t mail_box;
CanTxMsg TxMessage;

TxMessage.StdId=0;//标准格式为0 ，使用扩展格式
TxMessage.ExtId=0x1314;//使用扩展格式
TxMessage.IDE=CAN_Id_Extended;//配置使用标准格式还是扩展格式
TxMessage.RTR=CAN_RTR_Data;//配置是数据帧还是遥控帧
TxMessage.DLC=8;//发送的数据长度
for(i=0;i<8;i++)
{
    TxMessage.Data[i]=data[i];//存放数据
}
mail_box = CAN_Transmit(CAN2,&TxMessage);

5. 接收数据

//在终端中进行接收
void CAN2_RX0_IRQHandler(void)
{
	if(CAN_GetITStatus(CAN2,CAN_IT_FMP0)==SET)
	{
		CAN_Receive(CAN2, CAN_FIFO0,&RxMessage);
		printf("RxMessage.StdId:%x\r\n" ,RxMessage.StdId);
		printf("RxMessage.ExtId:%x\r\n" ,RxMessage.ExtId);
		printf("RxMessage.IDE:%x\r\n" 	,RxMessage.IDE);
		printf("RxMessage.RTR:%x\r\n"	,RxMessage.RTR);
		printf("RxMessage.DLC:%x\r\n"	,RxMessage.DLC);
		for(i=0;i<RxMessage.DLC;i++)
		{
			printf("RxMessage.Data[i]:%x\r\n",RxMessage.Data[i]);
		}
	}
}