EtherCAT主站对PHY有要求？

/**********************************************************************
 *                     EtherCAT主站对PHY有要求？
 * 说明：
 *     之前常听说EtherCAT主站对PHY有特殊的要求，于是找点资料确认一下，结论
 * 是没有什么特殊的要求，另外就是EtherCAT和CANOpen类似通过配置文件进行
 * 功能配置。
 *
 *                                2018-11-30 深圳 宝安西乡 曾剑锋
 *********************************************************************/

一、参考文档：
    . EtherCAT
        https://en.wikipedia.org/wiki/EtherCAT
    . EtherCAT主站开发经验——基于X86或ARM
        https://jingyan.baidu.com/article/6181c3e0844e7d152ef15332.html

二、Ethernet和EtherCAT在7层网络（ISO/OSI Reference Model）架构上的区别：
    . The TCP/IP Stack shown is not needed for typical fieldbus devices.
    . EtherCAT master can access all data including name and data types of an EtherCAT slave without complex tools.
    . EtherCAT uses Standard Ethernet (IEEE 802.3 - Ethernet MAC and PHY) without modifications.

三、 Device Profiles：
    The device profiles describe the application parameters and functional behavior of the devices, including device-specific state machines. The following software interfaces are provided for existing device profiles. Thus, the migration to EtherCAT by adjusting the firmware and the hardware is simplified significantly.