C语言按照EtherCAT协议，扫描多个伺服电机程序。MACRAM收发略，不用EtherCAT库。用C语言构建和解析ethercat帧写出程序

由于EtherCAT协议的复杂性，编写EtherCAT通信程序需要对该协议有较深入的理解。以下是一个简单的示例程序，用于扫描多个伺服电机。

#include <stdio.h>
#include <string.h>

#define ETHERCAT_FRAME_SIZE 1518

typedef struct {
    unsigned int header[2];
    unsigned char data[ETHERCAT_FRAME_SIZE];
} ethercat_frame_t;

typedef struct {
    unsigned char ID;
    unsigned char len;
    unsigned short index;
    unsigned char subindex;
    unsigned char data[4];
} sdo_t;

void send_ethercat_frame(ethercat_frame_t *frame) {
    // 发送EtherCAT帧的代码
}

void receive_ethercat_frame(ethercat_frame_t *frame) {
    // 接收EtherCAT帧的代码
}

void send_sdo(unsigned char ID, unsigned short index, unsigned char subindex, unsigned char *data, unsigned char len) {
    ethercat_frame_t frame;
    sdo_t sdo;

    memset(&frame, 0, sizeof(ethercat_frame_t));
    memset(&sdo, 0, sizeof(sdo_t));

    // 构建SDO帧
    sdo.ID = ID;
    sdo.len = len;
    sdo.index = index;
    sdo.subindex = subindex;
    memcpy(sdo.data, data, len);

    // 构建EtherCAT帧
    frame.header[0] = 0x00000000;
    frame.header[1] = 0x00000000;
    frame.data[0] = 0x02;
    frame.data[1] = 0x80 | (sdo.len > 4 ? 0x10 : 0x00) | ((6 + sdo.len) << 4);
    frame.data[2] = sdo.ID;
    frame.data[3] = sdo.index & 0xFF;
    frame.data[4] = (sdo.index >> 8) & 0xFF;
    frame.data[5] = sdo.subindex;
    memcpy(&frame.data[6], sdo.data, sdo.len);

    send_ethercat_frame(&frame);
}

void receive_sdo(unsigned char ID, unsigned short index, unsigned char subindex, unsigned char *data, unsigned char len) {
    ethercat_frame_t frame;
    sdo_t sdo;

    memset(&frame, 0, sizeof(ethercat_frame_t));
    memset(&sdo, 0, sizeof(sdo_t));

    // 构建SDO帧
    sdo.ID = ID;
    sdo.len = len;
    sdo.index = index;
    sdo.subindex = subindex;

    // 构建EtherCAT帧
    frame.header[0] = 0x00000000;
    frame.header[1] = 0x00000000;
    frame.data[0] = 0x01;
    frame.data[1] = 0x80 | (sdo.len > 4 ? 0x10 : 0x00) | ((6 + sdo.len) << 4);
    frame.data[2] = sdo.ID;
    frame.data[3] = sdo.index & 0xFF;
    frame.data[4] = (sdo.index >> 8) & 0xFF;
    frame.data[5] = sdo.subindex;

    send_ethercat_frame(&frame);

    // 接收EtherCAT帧并解析SDO数据
    receive_ethercat_frame(&frame);
    memcpy(data, &frame.data[6], len);
}

int main() {
    unsigned char data[4];

    // 扫描多个伺服电机
    for (unsigned char ID = 1; ID <= 32; ID++) {
        // 读取伺服电机的状态字
        receive_sdo(ID, 0x6041, 0x00, data, sizeof(data));
        printf("Motor %d status word: 0x%02X%02X%02X%02X\n", ID, data[3], data[2], data[1], data[0]);

        // 设置伺服电机的目标位置
        data[0] = 0x00;
        data[1] = 0x00;
        data[2] = 0x10;
        data[3] = 0x00;
        send_sdo(ID, 0x607A, 0x00, data, sizeof(data));
    }

    return 0;
}

该程序使用了ethercat_frame_t和sdo_t结构体来表示EtherCAT帧和SDO帧。send_ethercat_frame和receive_ethercat_frame函数用于发送和接收EtherCAT帧。send_sdo和receive_sdo函数则用于构建和解析SDO帧，并利用send_ethercat_frame和receive_ethercat_frame函数进行通信。程序主要通过循环扫描多个伺服电机，并读取其状态字，然后设置其目标位置。