RTOS: How can i run DC Mode in AM4379?And control SYNC0 at 100us.

Tool/software:TI-RTOS

Now,i build Ethercat project in AM4379.

Master:PC-Twincat3

Slave:AM4379

But,How can i run DC Mode in AM4379?

And, in DC mode, SYNC0 cycle why 1ms, the main data from the normal transceiver, if 100us can detect the waveform, but the data transceiver is not normal?