一、概述

由于项目需要在机车6A系统上运行，故在产品开发时需要用到STM32 bxCAN外设，总体来说STM32的CAN总线应用起来不是很复杂，仔细看资料很容易上手，并且有官方参考例程。

二、底层配置详解

2.1 GPIO初始化

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB,ENABLE);

GPIO_PinAFConfig(GPIOB,GPIO_PinSource8,GPIO_AF_CAN1);

GPIO_PinAFConfig(GPIOB,GPIO_PinSource9,GPIO_AF_CAN1);

GPIO_InitStructure.GPIO_Pin= GPIO_Pin_8 | GPIO_Pin_9;

GPIO_InitStructure.GPIO_Mode= GPIO_Mode_AF;

GPIO_InitStructure.GPIO_Speed= GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_OType= GPIO_OType_PP;

GPIO_InitStructure.GPIO_PuPd= GPIO_PuPd_UP;

GPIO_Init(GPIOB, &GPIO_InitStructure);

2.2 CAN单元初始化

RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN1,ENABLE);

CAN_InitStructure.CAN_TTCM = DISABLE;//禁止时间触发通信模式

CAN_InitStructure.CAN_ABOM = DISABLE;//禁止自动离线

CAN_InitStructure.CAN_AWUM = DISABLE;//禁止自动唤醒模式

CAN_InitStructure.CAN_NART = DISABLE;//禁止自动重传

CAN_InitStructure.CAN_RFLM = DISABLE;//接收FIFO锁定

CAN_InitStructure.CAN_TXFP = DISABLE;

CAN_InitStructure.CAN_Mode = CAN_Mode_Normal;

CAN_InitStructure.CAN_SJW = CAN_SJW_1tq;

2.3 CAN通信波特率设置

CAN_InitStructure.CAN_BS1 = CAN_BS1_6tq;

CAN_InitStructure.CAN_BS2 = CAN_BS2_8tq;

CAN_InitStructure.CAN_Prescaler = 2;

CAN_Init(CAN1, &CAN_InitStructure);

2.4 CAN通信滤波器设置

CAN_FilterInitStructure.CAN_FilterNumber = 0;

CAN_FilterInitStructure.CAN_FilterMode = CAN_FilterMode_IdMask;

CAN_FilterInitStructure.CAN_FilterScale = CAN_FilterScale_32bit;

CAN_FilterInitStructure.CAN_FilterIdHigh = 0x0000;

CAN_FilterInitStructure.CAN_FilterIdLow = 0x0000;

CAN_FilterInitStructure.CAN_FilterMaskIdHigh = 0x0000;

CAN_FilterInitStructure.CAN_FilterMaskIdLow = 0x0000;

CAN_FilterInitStructure.CAN_FilterFIFOAssignment = 0;

CAN_FilterInitStructure.CAN_FilterActivation = ENABLE;

CAN_FilterInit(&CAN_FilterInitStructure);

NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);

NVIC_InitStructure.NVIC_IRQChannel = CAN1_RX0_IRQn;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&NVIC_InitStructure);

2.5 使能FIFO0信息挂起中断

CAN_ITConfig(CAN1, CAN_IT_FMP0, ENABLE);

三、CAN模块接收中断函数

描述：每次接收8个字节，可以为标准帧或扩展帧。

CanRxMsg RxMessage;

void CAN1_RX0_IRQHandler(void)

{

uint8_t i;

CAN_Receive(CAN1, CAN_FIFO0, &RxMessage);

for(i=0;i

{

CAN_RxBuffer[i] = RxMessage.Data[i];

}

}

四、CAN发送函数

描述：1、每次发送8个字节。

2、变量tmpID为用户设置的扩展帧ID号。

CanTxMsg TxMessage;

void CAN_TransmitZDJCMessage(uint32_t tmpID)

{

uint8_t TransmitMailbox = 0;

TxMessage.StdId = tmpID>>18;

TxMessage.ExtId = tmpID&0x0003FFFF;

TxMessage.RTR = CAN_RTR_DATA;

TxMessage.IDE = CAN_ID_EXT;

TxMessage.DLC = 8;

TxMessage.Data[0]=1;

TxMessage.Data[1]=2

TxMessage.Data[2]=3;

TxMessage.Data[3]=4;

TxMessage.Data[4]=5;

TxMessage.Data[5]=6;

TxMessage.Data[6]=7;

TxMessage.Data[7]=8;

TransmitMailbox = CAN_Transmit(CAN1, &TxMessage);

while(CAN_TransmitStatus(CAN1,TransmitMailbox)!=1);

}

五、总结

本博文给出的CAN通信实例是经过修改后的程序，并非本人在项目中所使用的，当然项目中使用的程序比本博文写出的代码要复杂的多，并且做了通信超时措施。但本人可以保证本博文给出的历程是完全可以正常通信的，读者朋友可以根据自己的需求进行修改，如有问题可以留言。