convert CAN frame

前言

最近了解了一些socket can的知识点，本文主要介绍如何将数据转换为CAN报文，前提是已经确定CAN的传输协议。

本文使用的CAN报文共有22条，这些报文共用一个can id，每条报文使用序号标志；

报文协议

转换数据程序

char* convert_buf(vector<Point>& probp, vector<Distance>& pdist, vector<int>& plabel)
{
    //convert-can-frame.
    char buffer[][] = {  };
    for (int i = ; i < ; i++)
    {
        double lat_factor = 0.1;
        double long_factor = 0.2;

        unsigned int lat01 = static_cast<unsigned int>(pdist[ * i].x_dis / lat_factor);//unit-2dm-8bits.
        unsigned int long01 = static_cast<unsigned int>(pdist[ * i].y_dis / long_factor);//unit-2dm-9bits.
        int label01 = plabel[i*];

        if (i == )
        {
            buffer[i][] = (((i+) & 0xFF) << ) + ((long01 & 0x1FF) >> );
            buffer[i][] = ((long01 & 0x1FF) << ) + ((lat01 & 0xFF) >> );
            buffer[i][] = ((lat01 & 0xFF) << ) + (label01 & 0x03);
            break;
        }

        unsigned int lat02 = static_cast<unsigned int>(pdist[ * i + ].x_dis / lat_factor);//unit-2dm-8bits.
        unsigned int long02 = static_cast<unsigned int>(pdist[ * i + ].y_dis / long_factor);//unit-2dm-9bits.
        int label02 = plabel[ * i + ];

        unsigned int lat03 = static_cast<unsigned int>(pdist[ * i + ].x_dis / lat_factor);//unit-2dm-8bits.
        unsigned int long03 = static_cast<unsigned int>(pdist[ * i + ].y_dis / long_factor);//unit-2dm-9bits.
        int label03 = plabel[ * i + ];

        std::cout << "long01 --- " << long01 << "-- long02 --- " << long02 << "--- long03 --- " << long03 << std::endl;
        buffer[i][] = (((i + ) & 0xFF) << ) + ((long01 & 0x1FF) >> );
        buffer[i][] = ((long01 & 0x1FF) << ) + ((lat01 & 0xFF) >> );
        buffer[i][] = ((lat01 & 0xFF) << ) + (label01 & 0x03);
        buffer[i][] = ((long02 & 0x1FF) >> );
        buffer[i][] = ((long02 & 0x1FF) << ) + ((lat02 & 0xFF) >> );
        buffer[i][] = ((lat02 & 0xFF) << ) + ((label02 & 0x03) << ) + ((long03 & 0x1FF) >> );
        buffer[i][] = ((long03 & 0x1FF) << ) + ((lat03 & 0xFF) >> );
        buffer[i][] = ((lat03 & 0xFF) << ) + ((label03 & 0x03) << );

        printf("buffer[0]: --- %x\n", (byte)buffer[i][]);
        printf("buffer[1]: --- %x\n", (byte)buffer[i][]);
        printf("buffer[2]: --- %x\n", (byte)buffer[i][]);
        printf("buffer[3]: --- %x\n", (byte)buffer[i][]);
        printf("buffer[4]: --- %x\n", (byte)buffer[i][]);
        printf("buffer[5]: --- %x\n", (byte)buffer[i][]);
        printf("buffer[6]: --- %x\n", (byte)buffer[i][]);
        printf("buffer[7]: --- %x\n", (byte)buffer[i][]);

    }
    cout << "sizeof(buffer): " << sizeof(buffer) << " Byte..." << endl;
    return buffer[];

}

注意

1.如何确定CAN协议的格式，特别是信号的范围、精度以及比特位数；

2.浮点型数据如何变换为可以进行逻辑运算和位移操作的数据类型；

3.如何按照报文格式得到每个字节的内容，特别是位移操作；

4.如何将报文内容正确输出方便查看；

5.原始数据可能越界，应该在转换为报文数据之前对原始数据进行越界处理；

6.转换为CAN报文过程中的各个操作符号的优先级；

完