stm32can通信收发

STM32的CAN控制器支持CAN通信的收发功能。下面是一个简单的示例代码，演示了如何在STM32上进行CAN通信的收发操作：

#include "stm32f4xx.h"

// 定义CAN消息结构体
typedef struct {
  uint32_t id;       // 消息ID
  uint8_t  data[8];  // 数据
  uint8_t  len;      // 数据长度
} CAN_Message;

// 初始化CAN控制器
void CAN_Init(void) {
  // 使能CAN时钟
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN1, ENABLE);

  // 初始化CAN GPIO引脚
  GPIO_InitTypeDef GPIO_InitStruct;
  GPIO_InitStruct.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_8;
  GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOB, &GPIO_InitStruct);

  // 配置CAN引脚复用功能
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource8, GPIO_AF_CAN1);
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource9, GPIO_AF_CAN1);

  // CAN初始化结构体
  CAN_InitTypeDef CAN_InitStruct;
  CAN_InitStruct.CAN_TTCM = DISABLE;
  CAN_InitStruct.CAN_ABOM = DISABLE;
  CAN_InitStruct.CAN_AWUM = DISABLE;
  CAN_InitStruct.CAN_NART = DISABLE;
  CAN_InitStruct.CAN_RFLM = DISABLE;
  CAN_InitStruct.CAN_TXFP = DISABLE;
  CAN_InitStruct.CAN_Mode = CAN_Mode_Normal;
  CAN_InitStruct.CAN_SJW = CAN_SJW_1tq;
  CAN_InitStruct.CAN_BS1 = CAN_BS1_9tq;
  CAN_InitStruct.CAN_BS2 = CAN_BS2_8tq;
  CAN_InitStruct.CAN_Prescaler = 3;  // 波特率预分频器

  // 初始化CAN
  CAN_Init(CAN1, &CAN_InitStruct);

  // 启动CAN
  CAN_Cmd(CAN1, ENABLE);
}

// 发送CAN消息
void CAN_SendMessage(uint32_t id, uint8_t* data, uint8_t len) {
  CAN_Message message;
  message.id = id;
  message.len = len;
  memcpy(message.data, data, len);

  // 准备CAN消息
  CAN_TxMailBox_TypeDef* mailbox = CAN1->sTxMailBox;
  mailbox->TIR = (id << 21) | CAN_ID_STD | CAN_RTR_DATA;
  mailbox->TDTR = len;
  mailbox->TDLR = *((uint32_t*)data);
  mailbox->TDHR = *((uint32_t*)(data + 4));

  // 发送CAN消息
  mailbox->TIR |= CAN_TI0R_TXRQ;
}

// 接收CAN消息
void CAN_ReceiveMessage(CAN_Message* message) {
  // 检查是否有接收到的消息
  if (CAN_MessagePending(CAN1, CAN_FIFO0) > 0) {
    CAN_Receive(CAN1, CAN_FIFO0, &(message->id), message->data, &(message->len), CAN_Id_Standard);
  }
}

int main(void) {
  // 初始化CAN控制器
  CAN_Init();

  // 待发送的数据
  uint8_t sendData[] = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08};

  // 发送CAN消息
  CAN_SendMessage(0x123, sendData, sizeof(sendData));

  // 接收CAN消息
  CAN_Message receivedMessage;
  CAN_ReceiveMessage(&receivedMessage);

  // 打印接收到的消息
  printf("Received message ID: %x\n", receivedMessage.id);
  printf("Received message data: ");
  for (int i = 0; i < receivedMessage.len; i++) {
    printf("%02x ", receivedMessage.data[i]);
  }
  printf("\n");

  while (1) {
    // 主循环
  }
}

这段代码演示了如何在STM32上进行CAN通信的收发操作。首先，需要初始化CAN控制器，并配置相关的GPIO引脚。然后，可以使用`CAN_SendMessage`函数发送CAN消息，该函数接受消息ID、数据和数据长度作为参数。接收CAN消息可以使用`CAN_ReceiveMessage`函数，该函数将接收到的消息存储在`CAN_Message`结构体中。