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（1）定义配置信息

键入命令：ethercat cstruct 得到从机的配置信息，复制下来（我用的从机是简单的io开发板）

信息如下：

chenpeng@chenpeng-M219F-6C:/lib/modules$ ethercat cstruct
/* Master 0, Slave 0, "ServoDrive_FSMC"
 * Vendor ID:       0x00000009
 * Product code:    0x26483052
 * Revision number: 0x00020111
 */

ec_pdo_entry_info_t slave_0_pdo_entries[] = {
    {0x7010, 0x01, 1}, /* LED 1 */
    {0x7010, 0x02, 1}, /* LED 2 */
    {0x7010, 0x03, 1}, /* LED 3 */
    {0x7010, 0x04, 1}, /* LED 4 */
    {0x7010, 0x05, 1}, /* LED 5 */
    {0x7010, 0x06, 1}, /* LED 6 */
    {0x7010, 0x07, 1}, /* LED 7 */
    {0x7010, 0x08, 1}, /* LED 8 */
    {0x0000, 0x00, 8}, /* Gap */
    {0x7011, 0x00, 32}, /* Var0x7011_OUTPUTS */
    {0x6000, 0x01, 1}, /* Switch 1 */
    {0x6000, 0x02, 1}, /* Switch 2 */
    {0x6000, 0x03, 1}, /* Switch 3 */
    {0x6000, 0x04, 1}, /* Switch 4 */
    {0x6000, 0x05, 1}, /* Switch 5 */
    {0x6000, 0x06, 1}, /* Switch 6 */
    {0x6000, 0x07, 1}, /* Switch 7 */
    {0x6000, 0x08, 1}, /* Switch 8 */
    {0x0000, 0x00, 8}, /* Gap */
    {0x6020, 0x01, 1}, /* Underrange */
    {0x6020, 0x02, 1}, /* Overrange */
    {0x6020, 0x03, 2}, /* Limit 1 */
    {0x6020, 0x05, 2}, /* Limit 2 */
    {0x0000, 0x00, 8}, /* Gap */
    {0x1802, 0x07, 1}, /* TxPDOState */
    {0x1802, 0x09, 1}, /* TxPDO Toggle */
    {0x6020, 0x11, 16}, /* Analog input */
};

ec_pdo_info_t slave_0_pdos[] = {
    {0x1601, 10, slave_0_pdo_entries + 0}, /* DO RxPDO-Map */
    {0x1a00, 9, slave_0_pdo_entries + 10}, /* DI TxPDO-Map */
    {0x1a02, 8, slave_0_pdo_entries + 19}, /* AI TxPDO-Map */
};

ec_sync_info_t slave_0_syncs[] = {
    {0, EC_DIR_OUTPUT, 0, NULL, EC_WD_DISABLE},
    {1, EC_DIR_INPUT, 0, NULL, EC_WD_DISABLE},
    {2, EC_DIR_OUTPUT, 1, slave_0_pdos + 0, EC_WD_ENABLE},
    {3, EC_DIR_INPUT, 2, slave_0_pdos + 1, EC_WD_DISABLE},
    {0xff}
};

自己再定义需要注册的pdo entry

我的是：

const static ec_pdo_entry_reg_t domain1_regs[] = {

    {IO_OPS, IO_INFO, 0x7010, 0x01, &off_led1,&off_led1_bit},
    {IO_OPS, IO_INFO, 0x7010, 0x02, &off_led2,&off_led2_bit},
    {IO_OPS, IO_INFO, 0x7010, 0x03, &off_led3,&off_led3_bit},
    {IO_OPS, IO_INFO, 0x7010, 0x04, &off_led4,&off_led4_bit},
    {IO_OPS, IO_INFO, 0x7010, 0x05, &off_led5,&off_led5_bit},
    {IO_OPS, IO_INFO, 0x7010, 0x06, &off_led6,&off_led6_bit},
    {IO_OPS, IO_INFO, 0x7010, 0x07, &off_led7,&off_led7_bit},
    {IO_OPS, IO_INFO, 0x7010, 0x08, &off_led8,&off_led8_bit},
    {IO_OPS, IO_INFO, 0x6000, 0x01, &off_switch1,&off_switch1_bit},
    {IO_OPS, IO_INFO, 0x6000, 0x02, &off_switch2,&off_switch2_bit},
    {IO_OPS, IO_INFO, 0x6000, 0x03, &off_switch3,&off_switch3_bit},
    {IO_OPS, IO_INFO, 0x6000, 0x04, &off_switch4,&off_switch4_bit},
    {IO_OPS, IO_INFO, 0x6000, 0x05, &off_switch5,&off_switch5_bit},
    {IO_OPS, IO_INFO, 0x6000, 0x06, &off_switch6,&off_switch6_bit},
    {IO_OPS, IO_INFO, 0x6000, 0x07, &off_switch7,&off_switch7_bit},
    {IO_OPS, IO_INFO, 0x6000, 0x08, &off_switch8,&off_switch8_bit},
    {}
};

（2）程序初始化

在实时操作系统中请求一个master

master	  = ecrt_request_master( 0 );
	if(master == NULL) goto error_out;
	printf("master found\n");

创建新的过程数据domain,domain用来注册pods以及在循环周期中交换pdos的。

domain  = ecrt_master_create_domain(master);
	if (!domain) {
		printf("config domain failed\n");
        return 0;
    }

创建从机配置信息

slave   = ecrt_master_slave_config(master,0,0,IO_INFO);
    if (!slave) {
		printf("config slave failed\n");
        return 0;
    }
	

指定一个完整的pdo配置信息

if (ecrt_slave_config_pdos(slave, EC_END, slave_0_syncs))
	{
    	fprintf(stderr, "Failed to configure PDOs.\n");
    	return 1;
    }

把pdo的entry注册到domain中去

if (ecrt_domain_reg_pdo_entry_list(domain, domain1_regs)) {
        fprintf(stderr, "PDO entry registration failed!\n" );
        return 1;
    }

激活master

if ( ecrt_master_activate((ec_master_t*)master) )
        return -1;

获取被映射的domain内存（在用户空间中，必须在激活master后来调用他）

if (!(domain_pd = ecrt_domain_data(domain))) {
		fprintf(stderr, "config Domain Data failed!\n" );
		return 1;
	}

执行周期任务

 while (1) {
	usleep( 1 );
	cyclic_task(master,domain,&(domain_pd));
    }

周期任务，仅当参考

void cyclic_task(ec_master_t* master,ec_domain_t* domain1, uint8_t **domain1_pd )
{
    static unsigned int counter = 0;

    /* receive process data */
    ecrt_master_receive(master);
    ecrt_domain_process(domain1);

    if (counter) {
        counter--;
    } else { /* do this at 1 Hz */
        counter = FREQUENCY;
       /* read process data */

       printf("SWITCH = %d ,  %d , %d\n",
	   EC_READ_U8(*domain1_pd + off_switch1),
	   EC_READ_U8(*domain1_pd + off_switch2),
	   EC_READ_U8(*domain1_pd + off_switch3)
       );

       printf( "LED= %d ,  %d , %d\n",
	   EC_READ_U8(*domain1_pd + off_led1),
	   EC_READ_U8(*domain1_pd + off_led2),
	   EC_READ_U8(*domain1_pd + off_led3)
       );
    }
    /* send process data */
	EC_WRITE_U8(*domain1_pd + off_led1,0x20);

    ecrt_domain_queue(domain1);
    ecrt_master_send(master);
}