C语言CAN总线代码

CAN（Controller Area Network）总线是一种工业标准串行通信协议，常用于汽车、航空等领域。在C语言中编写CAN总线控制代码通常会涉及专门的库，如Linux下的libcan或QNX的qcan，以及一些硬件驱动支持。

以下是一个简单的示例，展示如何使用`libcan`库在Linux下发送和接收CAN数据：

#include <stdio.h>
#include <stdlib.h>
#include <linux/can.h> // Linux CAN API

#define CAN_IFACE "can0" // 设定CAN接口名，例如对于一体机通常是ethcan0等
#define CAN_ID 0x123456  // 数据帧ID

void send_can_message(struct can_frame* msg) {
    struct can_ioctl cmd = {0};
    cmd.type = CAN_IOCTLsnd;
    cmd.fd = open(CAN_IFACE, O_RDWR | O_NONBLOCK);
    if (cmd.fd == -1) {
        perror("Failed to open CAN interface");
        return;
    }

    msg->can_id = CAN_ID; // 设置CAN ID
    msg->can_dlc = sizeof(msg->data); // 设置数据长度
    memcpy(msg->data, "Hello CAN", sizeof(msg->data)); // 设置数据

    int ret = ioctl(cmd.fd, SIOCOUTCAN, &msg);
    if (ret != 0) {
        perror("Failed to send CAN message");
        close(cmd.fd);
    } else {
        printf("Sent CAN message with ID 0x%x\n", CAN_ID);
    }
    close(cmd.fd);
}

void receive_can_message(struct can_frame* msg, unsigned int timeout_ms) {
    struct pollfd pfd;
    pfd.fd = open(CAN_IFACE, O_RDONLY | O_NONBLOCK);
    pfd.events = POLLIN;

    while (poll(&pfd, 1, timeout_ms * 1000) > 0) {
        ssize_t bytes_read = read(pfd.fd, msg, sizeof(*msg));
        if (bytes_read >= sizeof(*msg)) {
            printf("Received CAN message with ID 0x%x and data: %.*s\n",
                   ntohs(msg->can_id), msg->can_dlc, msg->data);
        }
    }

    if (pfd.revents & POLLERR) {
        perror("Error receiving CAN message");
    }
    close(pfd.fd);
}

int main() {
    struct can_frame send_msg, recv_msg;
    send_can_message(&send_msg);
    receive_can_message(&recv_msg, 1000); // 设置接收超时为1秒
    return 0;
}