STM32 CAN协议编写

STM32 CAN协议编写主要包括以下几个步骤：

1. 配置CAN硬件参数：在STM32芯片的寄存器中设置CAN总线的波特率、传输模式、过滤器、中断等参数。

2. 初始化CAN控制器：在软件中初始化CAN控制器，并设置中断优先级和中断回调函数等。

3. 发送CAN数据帧：设置CAN标识符、数据长度和数据内容等信息，将数据帧发送到CAN总线上。

4. 接收CAN数据帧：配置CAN过滤器以接收指定标识符的CAN数据帧，并在中断回调函数中处理接收到的数据帧。

下面是一个简单的CAN发送程序示例：

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

void CAN_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    CAN_InitTypeDef CAN_InitStructure;

    /* Enable GPIO clock */
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);

    /* Enable CAN clock */
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN1, ENABLE);

    /* Configure CAN pin: RX */
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
    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);

    /* Configure CAN pin: TX */
    GPIO_InitStructure.GPIO_Pin = 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);

    /* Connect CAN pins to AF */
    GPIO_PinAFConfig(GPIOB, GPIO_PinSource8, GPIO_AF_CAN1);
    GPIO_PinAFConfig(GPIOB, GPIO_PinSource9, GPIO_AF_CAN1);

    /* CAN configuration */
    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_InitStructure.CAN_BS1 = CAN_BS1_6tq;
    CAN_InitStructure.CAN_BS2 = CAN_BS2_7tq;
    CAN_InitStructure.CAN_Prescaler = 2;
    CAN_Init(CAN1, &CAN_InitStructure);

    /* Enable CAN interrupt */
    NVIC_InitTypeDef NVIC_InitStructure;
    NVIC_InitStructure.NVIC_IRQChannel = CAN1_RX0_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
}

void CAN_Send(uint32_t id, uint8_t* data, uint8_t len)
{
    CanTxMsg TxMessage;

    /* Fill the transmit message */
    TxMessage.StdId = id;
    TxMessage.IDE = CAN_Id_Standard;
    TxMessage.RTR = CAN_RTR_Data;
    TxMessage.DLC = len;
    for (int i = 0; i < len; i++) {
        TxMessage.Data[i] = data[i];
    }

    /* Send the message */
    while (CAN_Transmit(CAN1, &TxMessage) == CAN_TxStatus_NoMailBox);
}

void CAN1_RX0_IRQHandler(void)
{
    CanRxMsg RxMessage;

    /* Get the received message */
    CAN_Receive(CAN1, CAN_FIFO0, &RxMessage);

    /* Process the received message */
    // ...
}

以上是一个简单的CAN发送程序示例，涉及到了CAN硬件参数配置、CAN控制器初始化、CAN数据帧发送等操作。需要根据具体需求进行修改。