ethercat样例

以下是一个使用 EtherCAT 通信的简单样例：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ethercat.h>

#define NUM_OF_ELMO_SLAVES 1
#define EC_TIMEOUTMON 500

int expectedWKC;
volatile int wkc;
ec_slave_config_t sc[NUM_OF_ELMO_SLAVES];

void check_domain_state(void) {
    ec_domain_state_t ds;
    ecrt_master_receive(master, EC_TIMEOUTRET, &ds);
    ecrt_domain_state(domain[0], &ds);
    if (ds.working_counter != wkc) {
        printf("domain0: WC %u.\n", ds.working_counter);
        wkc = ds.working_counter;
    }
}

void cyclic_task(void) {
    static int cnt = 0;
    uint8_t *domain1_pd = ecrt_domain_data(domain[0]);

    if (cnt > 1000) {
        cnt = 0;
    }

    // Write data to PDOs
    int32_t pos = cnt * 100;
    int16_t torque = cnt * 10;
    memcpy(domain1_pd + 0x00, &pos, sizeof(pos));
    memcpy(domain1_pd + 0x04, &torque, sizeof(torque));

    cnt++;
}

int main() {
    printf("Starting Elmo Example\n");

    // Initialize EtherCAT master
    if (ecrt_master_open(&master, 0) != 0) {
        printf("Failed to open EtherCAT master!\n");
        return -1;
    }

    // Initialize EtherCAT slave configuration
    if (ecrt_master_slave_config_init(master, NUM_OF_ELMO_SLAVES, slave_info) != 0) {
        printf("Failed to initialize EtherCAT slave configuration!\n");
        return -1;
    }

    // Get slave configuration
    for (int i = 0; i < NUM_OF_ELMO_SLAVES; i++) {
        if (!(sc[i] = ecrt_master_slave_config_find(master, i + 1))) {
            printf("Failed to get slave %d configuration!\n", i + 1);
            return -1;
        }
    }

    // Create EtherCAT domain
    if (!(domain = ecrt_master_create_domain(master))) {
        printf("Failed to create EtherCAT domain!\n");
        return -1;
    }

    // Configure slave PDOs
    for (int i = 0; i < NUM_OF_ELMO_SLAVES; i++) {
        if (ecrt_slave_config_pdos(sc[i], 0, slave_0_pdo_entries, slave_0_pdo_details) != NUM_OF_0_ENTRIES) {
            printf("Failed to configure PDOs for slave %d!\n", i + 1);
            return -1;
        }
    }

    // Configure EtherCAT domain
    if (ecrt_domain_reg_pdo_entry_list(domain[0], domain_regs) < 0) {
        printf("Failed to configure EtherCAT domain!\n");
        return -1;
    }

    // Activate master
    if (ecrt_master_activate(master) != 0) {
        printf("Failed to activate EtherCAT master!\n");
        return -1;
    }

    printf("EtherCAT master activated.\n");

    // Set expected working counter
    expectedWKC = (ecrt_slave_config_max_data_size(sc[0]) / 2) + (ecrt_slave_config_watchdog_time(sc[0]) * 2) + 6;

    // Start cyclic task
    while (!done && (cyclic_count < 100000)) {
        // Wait for next cycle
        ecrt_master_receive(master, EC_TIMEOUTRET, &wkc);
        check_domain_state();

        if (wkc >= expectedWKC) {
            cyclic_task();
            ecrt_domain_queue(domain[0], ecrt_domain_data(domain[0]), PDO_SIZE);
        } else {
            printf("Working counter not expected.\n");
        }

        ecrt_master_send(master);
        usleep(1000);
    }

    // Deactivate master
    ecrt_master_deactivate(master);
    ecrt_master_destroy(master);

    printf("Master deactivated.\n");

    return 0;
}

该样例中，使用了 EtherCAT 库的相关函数，例如 `ecrt_master_open()` 用于打开 EtherCAT 主站，`ecrt_master_slave_config_init()` 用于初始化从站配置等。在 `cyclic_task()` 函数中，将数据写入 PDO ，并在每个循环周期内执行。

需要注意的是，该样例中的从站配置、PDO 映射、PDO 数据等需要根据实际硬件进行修改。