Q: How is the OMAP-L138 SOM-M1 UART0 used, since the signal lines are muxed with the Ethernet PHY on the MII bus?

A:
UART0 is muxed as the MII bus for the Ethernet PHY on the
module. You may be able to get access to the UART0 interface by putting
the ethernet into isolate mode, and then changing the pinmux of the MII
bus (assuming you do not need access to the ethernet at the same time).

The data sheet for the LAN8710 chip is located here:
http://media.digikey.com/...ets/SMSC/LAN8710.pdf

You can refer to section 4.14.1 for information on how to program the
PHY registers, and section 5.1 for register information. The bit to set
the chip into isolate mode is bit 10 of register 0. Please note that the
Ethernet chip is not put into isolate mode on startup, so this procedure
will need to be repeated after every power cycle.

PRODUCTS Included:
OMAP-L138, AM1808, C6748