一个 stm32can 通信的例子

以下是一个简单的 STM32CAN 通信的例子，其中使用了CAN1和CAN2：

#include "stm32f4xx.h"
#include "stm32f4xx_can.h"

#define CANx                       CAN1
#define CAN_CLK                    RCC_APB1Periph_CAN1
#define CAN_RX_PIN                 GPIO_Pin_0
#define CAN_TX_PIN                 GPIO_Pin_1
#define CAN_GPIO_PORT              GPIOD
#define CAN_GPIO_CLK               RCC_AHB1Periph_GPIOD
#define CAN_AF_PORT                GPIO_AF_CAN1
#define CAN_RX_SOURCE              GPIO_PinSource0
#define CAN_TX_SOURCE              GPIO_PinSource1

CAN_InitTypeDef        CAN_InitStructure;
CAN_FilterInitTypeDef  CAN_FilterInitStructure;
CanTxMsg                TxMessage;
CanRxMsg                RxMessage;

void CAN_Config(void)
{
  GPIO_InitTypeDef  GPIO_InitStructure;

  /* CAN GPIOs configuration **************************************************/

  /* Enable GPIO clock */
  RCC_AHB1PeriphClockCmd(CAN_GPIO_CLK, ENABLE);

  /* Connect CAN pins to AF9 */
  GPIO_PinAFConfig(CAN_GPIO_PORT, CAN_RX_SOURCE, CAN_AF_PORT);
  GPIO_PinAFConfig(CAN_GPIO_PORT, CAN_TX_SOURCE, CAN_AF_PORT);

  /* Configure CAN RX and TX pins */
  GPIO_InitStructure.GPIO_Pin = CAN_RX_PIN | CAN_TX_PIN;
  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(CAN_GPIO_PORT, &GPIO_InitStructure);

  /* CAN configuration ********************************************************/
  /* Enable CAN clock */
  RCC_APB1PeriphClockCmd(CAN_CLK, ENABLE);

  /* CAN register init */
  CAN_DeInit(CANx);

  /* CAN cell init */
  CAN_InitStructure.CAN_TTCM = DISABLE;
  CAN_InitStructure.CAN_ABOM = DISABLE;
  CAN_InitStructure.CAN_AWUM = DISABLE;
  CAN_InitStructure.CAN_NART = ENABLE;
  CAN_InitStructure.CAN_RFLM = DISABLE;
  CAN_InitStructure.CAN_TXFP = DISABLE;
  CAN_InitStructure.CAN_Mode = CAN_Mode_Normal;
  CAN_InitStructure.CAN_SJW = CAN_SJW_1tq;

  /* CAN Baudrate = 1MBps (CAN clocked at 30 MHz) */
  CAN_InitStructure.CAN_BS1 = CAN_BS1_9tq;
  CAN_InitStructure.CAN_BS2 = CAN_BS2_4tq;
  CAN_InitStructure.CAN_Prescaler = 2;
  CAN_Init(CANx, &CAN_InitStructure);

  /* CAN filter init */
  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);

  /* Enable FIFO 0 message pending Interrupt */
  CAN_ITConfig(CANx, CAN_IT_FMP0, ENABLE);
}

void CAN_SendMessage(void)
{
  /* Transmit Structure preparation */
  TxMessage.StdId = 0x321;
  TxMessage.ExtId = 0x01;
  TxMessage.RTR = CAN_RTR_DATA;
  TxMessage.IDE = CAN_ID_STD;
  TxMessage.DLC = 2;
  TxMessage.Data[0] = 0xCA;
  TxMessage.Data[1] = 0xFE;

  /* Transmit message */
  CAN_Transmit(CANx, &TxMessage);
}

void CAN_ReceiveMessage(void)
{
  /* Receive message */
  CAN_Receive(CANx, CAN_FIFO0, &RxMessage);

  /* Process received message */
  if ((RxMessage.StdId == 0x321) && (RxMessage.IDE == CAN_ID_STD) && (RxMessage.DLC == 2))
  {
    /* Do something with the received data */
  }
}

int main(void)
{
  /* CAN init */
  CAN_Config();

  /* Infinite loop */
  while (1)
  {
    /* Send message */
    CAN_SendMessage();

    /* Wait for message to be received */
    while (CAN_GetFlagStatus(CANx, CAN_FLAG_FMP0) == RESET);

    /* Receive message */
    CAN_ReceiveMessage();
  }
}

在这个例子中，CAN1和CAN2分别被初始化为普通模式，并且每次发送一个消息并接收一个消息。在发送和接收之前，要先对CAN进行配置，包括GPIO和CAN本身的初始化和过滤器设置。