BECKHOFF EtherCAT Technology Section I - Manual (Page 45)

Ethernet Physical Layer
Slave Controller – Technology I-25
5.8.3 ESCs with native FX support
ESCs with native FX support have individual PHY reset outputs for each port. This PHY reset output is
intended to hold the PHY and the transceiver in reset state while the ESC is in reset state, and
additionally, to issue a reset cycle when a link failure is detected by the enhanced link detection
mechanism.
If at least one port is configured for FX operation, all ports have to use the individual PHY reset
outputs. This is especially important for enhanced link detection, since all the PHY reset outputs are
used for link down signaling instead of auto-negotiation restart, which is not used anymore
–
regardless of the port using FX or TX.
5.8.4 ESCs without native FX support
ESCs without native FX support require special attention regarding reset connection, link down
signaling and enhanced link detection. External logic might be required.
5.9 Gigabit Ethernet PHYs
Gigabit Ethernet PHYs can generally be used for EtherCAT, as long as the link speed is restricted to
100 Mbit/s, either by strapping options of the PHY or by using the auto negotiation advertisement.
Some ESCs are capable of restricting the auto negotiation advertisement of Gigabit Ethernet PHYs to
100 Mbit/s full-duplex if MI link detection and configuration is enabled.
Nevertheless, all other requirements of EtherCAT have to be fulfilled – especially the link loss reaction
time (Enhanced Link Detection might be required).