TMS320F28388D: For EtherCAT, How can I accesss PHY own register by ET1100 IP core?

For EtherCAT, How can I accesss PHY own register by ET1100 IP core?

For EtherCAT I selectied KSZ8061MNG PHY. There is a problem with the link.

At TMDSCNCD28388D board has no problems. but my custom board has a problems.

The difference between the two boards is the PHY.

So I read PHY Selection Guide and KSZ8061MNG datasheet, I found one thing I thought was the problem.

EtherCAT PHY Selection Guide says "Disable Fixed RX PHY latency".

But KSZ8061MNG says "Fixed RX PHY latency is default"

So I want to change this register to 1. but it was not changed by pull up/down resistor strap at PHY power on.

Maybe, It is changed by MDC/MDIO Management only.

So I want to control MDIO on ET1100. But I couldn't find such a way that using ET1100 registor.

 How can I accesss PHY own register by ET1100 IP core?

I have already asked the same question to BECKHOFF and I'm waiting for an answer.