STM32F042 简单的CAN总线操作例程，测试过的；
CanRxMsg g_CanRxMsg;
CanTxMsg g_CanTxMsg;
uint8_t CANInit(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
CAN_InitTypeDef CAN_InitStructure;
CAN_FilterInitTypeDef CAN_FilterInitStructure;
// Connect CAN pins to AF4
GPIO_PinAFConfig(GPIOA, GPIO_PinSource11, GPIO_AF_4);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource12, GPIO_AF_4);
//CAN_RX引脚
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;
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_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStructure);
//CAN_TX引脚
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStructure);
//Enable CAN clock
RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN, ENABLE);
//SYSCFG->CFGR1 |= SYSCFG_CFGR1_PA11_PA12_RMP; //TQFP32封装不需要此行
//CAN register init
CAN_DeInit(CAN);
CAN_StructInit(&CAN_InitStructure);
//CAN cell init
CAN_InitStructure.CAN_TTCM = DISABLE;
CAN_InitStructure.CAN_ABOM = DISABLE;
CAN_InitStructure.CAN_AWUM = DISABLE;
CAN_InitStructure.CAN_NART = ENABLE;//禁止自动重发
CAN_InitStructure.CAN_RFLM = DISABLE;
CAN_InitStructure.CAN_TXFP = DISABLE;
CAN_InitStructure.CAN_Mode = CAN_Mode_Normal;
//CAN Baudrate = 10KBps (CAN clocked at 48 MHz)
CAN_InitStructure.CAN_SJW = CAN_SJW_1tq;
CAN_InitStructure.CAN_BS1 = CAN_BS1_3tq;
CAN_InitStructure.CAN_BS2 = CAN_BS2_2tq;
CAN_InitStructure.CAN_Prescaler = 800; //baud=48m/800/(1+3+2)=10k
if( CAN_Init(CAN, &CAN_InitStructure) != CANINITOK )
return 1;
// CAN filter init 接收所有数据包
CAN_FilterInitStructure.CAN_FilterNumber = 0; //激活第一组过滤器
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 = CAN_FIFO0;
CAN_FilterInitStructure.CAN_FilterActivation = ENABLE;
CAN_FilterInit(&CAN_FilterInitStructure);
//NVIC configuration
NVIC_InitStructure.NVIC_IRQChannel = CEC_CAN_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPriority = 0x0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
//Enable FIFO 0 message pending Interrupt
CAN_ITConfig(CAN, CAN_IT_FMP0, ENABLE);
//发送缓冲区初始化
g_CanTxMsg.StdId = 0;
g_CanTxMsg.ExtId = 0;
g_CanTxMsg.RTR = CAN_RTR_DATA;
g_CanTxMsg.IDE = CAN_ID_STD;
g_CanTxMsg.DLC = 8;
return 0;
}
//CAN中断
void CEC_CAN_IRQHandler(void)
{
//只打开了接收中断
CAN_Receive(CAN, CAN_FIFO0, &g_CanRxMsg);
//...
}
//发送一个数据包
void CAN_Send(uint8_t *buf,uint8_t len)
{
uint8_t i;
uint8_t size;
size=len<8?len:8;
for(i=0;i<size;i++)
g_CanTxMsg.Data[i]=buf[i];
g_CanTxMsg.DLC=size;
CAN_Transmit(CAN, &g_CanTxMsg);
}
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