本人学习STM32_CAN通信协议，参考博主代码,提几个疑问！

[ZzlYang]

本人使用STM32F103ZET6型号单片机，CAN1的TX RX引脚复用到GPIOD_0和GPIOD_1上面。

在参考了博主的资料后以下是本人的GPIO初始化代码，如有问题还请帮忙指正！

static void CANPort_GPIO_Config(void)
{	
	/*-----------------1.使能GPIO_D并重映射为CAN1---------------------*/
	/*-----------------1.1使能GPIO_D1 CAN TX引脚---------------------*/
	 GPIO_InitTypeDef  GPIO_InitStructure;
	 RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD | RCC_APB2Periph_AFIO, ENABLE); 		//使能GPIOD的时钟                                                                
   RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN1, ENABLE);    //使能CAN1时钟
	 
	 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
	 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;			//CAN TX发送引脚
	 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	 GPIO_Init(GPIOD,&GPIO_InitStructure);
	
	/*-----------------1.2使能GPIO_D0 CAN RX引脚---------------------*/
	 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;  //上拉输入
	 GPIO_InitStructure.GPIO_Pin  = GPIO_Pin_0;
	 GPIO_Init(GPIOD,&GPIO_InitStructure);			//初始化TX引脚

	 
	 GPIO_PinRemapConfig(GPIO_Remap2_CAN1,  ENABLE);
	
	

}

static void CAN_Mod_Config(void)
{		
	/*--------CAN配置结构体---------------*/
		CAN_InitTypeDef CAN_InitStructure;
		CAN_FilterInitTypeDef   CAN_FilterInitStructure;
		CAN_DeInit(CAN1);											//CAN结构体复位
		CAN_StructInit(&CAN_InitStructure);		//CAN结构体初始化
#if CAN_INT_ENABLE
    NVIC_InitTypeDef        NVIC_InitStructure;	 
#endif
//	  CAN_InitStructure.CAN_TTCM=DISABLE; //MCR-TTCM 关闭时间触发通信模式使能
//		CAN_InitStructure.CAN_ABOM=ENABLE; //MCR-ABOM 使能自动离线管理
//		CAN_InitStructure.CAN_AWUM=ENABLE; //MCR-AWUM 使用自动唤醒模式
//		CAN_InitStructure.CAN_NART=DISABLE; //MCR-NART 禁止报文自动重传
//		CAN_InitStructure.CAN_RFLM=DISABLE; //MCR-RFLM 接收 FIFO 不锁定
	/*------------------设置CAN的工作模式-------------------------*/
		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= CAN_Mode_Normal;  //模式设置：CAN_Mode_Normal 普通模式，CAN_Mode_LoopBack 回环模式;
		
	/*--------------------设置CAN的通信速率----------------------------*/
	//CANbps= Fpclk/((BRP+1)*((Tseg1+1)+(Tseg2+1)+1)
	//例如CANbps=APB1总线频率30000000/4/(8+6+1))=500k bps
	//总体配置方向: Tseg1>=Tseg2  Tseg2>=tq; Tseg2>=2TSJW 
			CAN_InitStructure.CAN_SJW=CAN_SJW_1tq;  //设置项目（1~4）
			CAN_InitStructure.CAN_BS1=CAN_BS1_6tq; //设置项目（1~16）
			CAN_InitStructure.CAN_BS2=CAN_BS2_3tq; //设置项目（1~8）
			CAN_InitStructure.CAN_Prescaler=10;			//设置项目（1~1024）
		
			CAN_Init(CAN1,&CAN_InitStructure);
		/*---------------设置过滤器------------------------*/
		CAN_FilterInitStructure.CAN_FilterNumber = 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;    //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_INT_ENABLE 	//以下是用于CAN中断方式接收的设置
    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
}