TMS570LC4357: How to use UART between two USB mini port ?

Dear TI Expert,

I have to plan use UART with TMS570LC4357's USB mini port to the other USB mini port.

However, I can't communicate with this configuration.

I tried it with PC USB Type-A.

That's OK.

And test it with TI AM5728's USB Type-A.

It's also OK.

Is there any method to communicate UART between two USB mini port ?

If I can't do this how about design USB Type-A circuit on TMS570 HDK board ?

Is it possible ?

I already finished to communicate with CAN and Ethernet.

But I wanna use USB mini port, too.

Is there any method to do it ?

And why mini port can't use UART ?

Sincerly,

Sanghoon