18. EtherCAT 主站

18.1. Depend on SDK1.10.0

18.2. Overview

This section is mainly based on the open-source EtherCAT master CherryECAT, demonstrating the EtherCAT master functionality running on HPMicro MCUs.

18.3. Feature

  • ~ 4K ram, ~40K flash(24K + 16K shell cmd, including log)

  • Asynchronous queue-based transfer (one transfer can carry multiple datagrams)

  • Zero-copy technology: directly use enet tx/rx buffer to fill and parse ethercat data

  • Support hot-plugging

    • Automatic scanning bus

    • Automatic updating slave information when the topology changes

  • Support automatic monitoring slave status

  • Support distributed clocks

  • Support CANopen over EtherCAT(COE)

  • Support File over EtherCAT(FOE)

  • Support Ethernet over EtherCAT(EOE)

  • Support Slave SII access

  • Support Slave register access

  • Support multi master

  • Minimum PDO cyclic time < 40 us (depends on master and slave hardware)

  • DC jitter < 3us (depends on master and slave hardware)

  • Support ethercat cmd with shell, ref to IgH

The pic shows dc jitter < 3us (hpm6800evk with flash_xip): ethercat

18.4. Running the example

The default demo uses shell to test ethercat slave.

ethercat ethercat ethercat ethercat ethercat ethercat ethercat ethercat

  • start pdo transfer with 1ms cycle

ec_start 1000

  • control led onoff with ecat_io demo

ethercat pdo_write -p 0 0 0x00
ethercat pdo_write -p 0 0 0x01
ethercat pdo_write -p 0 0 0x02
ethercat pdo_write -p 0 0 0x03

  • control motor in CSV mode with ecat_coe demo

ethercat pdo_write -p 0 0 0x0f // motor on
ethercat pdo_write -p 0 2 0xFF000000 // change ObjTargetVelocity to 255, hexdata from low byte to high byte
ethercat pdo_read -p 0 // get ObjStatusWord and ObjPositionActualValue
ethercat pdo_write -p 0 0 0x00 // motor off

18.5. API

Refer to CherryECAT API ：https://cherryecat.readthedocs.io/zh-cn/latest/api.html