BECKHOFF EtherCAT Technology Section I - Manual (Page 6)

CONTENTS
I-VI Slave Controller – Technology
CONTENTS
1 EtherCAT Slave Controller Overview 1
1.1 EtherCAT Slave Controller Function Blocks 2
1.2 Further Reading on EtherCAT and ESCs 3
1.3 Scope of Section I 3
2 EtherCAT Protocol 4
2.1 EtherCAT Header 4
2.2 EtherCAT Datagram 5
2.3 EtherCAT Addressing Modes 6
2.3.1 Device Addressing 7
2.3.2 Logical Addressing 7
2.4 Working Counter 8
2.5 EtherCAT Command Types 9
3 Frame Processing 12
3.1 Loop Control and Loop State 12
3.2 Frame Processing Order 14
3.3 Permanent Ports and Bridge Port 15
3.4 Shadow Buffer for Register Write Operations 15
3.5 Circulating Frames 15
3.5.1 Unconnected Port 0 16
3.6 Non-EtherCAT Protocols 16
3.7 Special Functions of Port 0 16
4 Physical Layer Common Features 17
4.1 Link Status 17
4.2 Selecting Standard/Enhanced Link Detection 18
4.3 FIFO Size Reduction 19
4.4 Frame Error Detection 19
5 Ethernet Physical Layer 20
5.1 Requirements to Ethernet PHYs 20
5.2 PHY reset and Link partner notification/loop closing 20
5.3 MII Interface 21
5.4 RMII Interface 22
5.5 RGMII Interface 22
5.5.1 RGMII In-Band Link Status 22
5.6 Link Detection 22
5.6.1 LINK_MII Signal 22
5.6.2 MI Link Detection and Configuration 23
5.7 Standard and Enhanced MII Link Detection 23
5.8 EtherCAT over Optical Links (FX) 24
5.8.1 Link partner notification and loop closing 24