Texas Instruments OMAP5912 Reference Manual page 1535

4.2.6 System-Level OTG Considerations
4.3 Pin Multiplexing
SPRU761A
The OMAP5912 USB OTG implementation allows up to two separate USB
host controller ports to function in parallel with an OTG link. The USB OTG
specification states that an OTG dual-role device has only one USB connector.
If a system implements an OTG connector, the system can only use the other
two USB host controller ports for on-board connectivity.
An OTG implementation using an OTG transceiver that is based on the OTG
Transceiver Interface Specification can use the transceiver autoconnect
feature. Enabling this OTG transceiver feature when OMAP5912 is acting as
a default-A dual-role On-The-Go device eases the timing requirements on
system software during an HNP transition from OMAP5912 acting as an
A-host to OMAP5912 acting as an A-peripheral.
A system that implements an OTG controller has a USB mini-AB receptacle.
This receptacle is used with an OTG cable to connect the system to another
OTG system. It is possible to connect a non-OTG USB device to the
OMAP5912-based OTG system mini-AB receptacle using an adapter cable as
defined in the On-The-Go supplement to the USB specification. If the system
supports this option, it may be necessary to provide a VBUS source with larger
current source capability than is typically available through an OTG
transceiver.
OMAP5912 USB signal multiplexing determines which USB functionality is
available at which OMAP5912 pins. OMAP5912 provides three pin groups that
can be configured to provide up to three simultaneous USB ports. These ports
can be configured to provide a USB OTG port, a USB device port, and/or up
to three USB host ports. When OMAP5912 is configured to provide USB OTG
functionality at one pin group, it is not possible to configure another pin group
to act as a USB device, because there is only one USB device controller and
it is used by the OTG functionality.
A USB transceiver is needed for each USB port used in the system. It converts
between signaling appropriate for the OMAP5912 USB controllers and
signaling appropriate for the USB wire. OMAP5912 USB functionality includes
support for several types of USB transceivers. OMAP5912 provides one
integrated USB transceiver suitable for a single USB host or USB device port,
but it is not capable of acting as a USB OTG transceiver. OMAP5912 provides
signaling to up to two external USB transceivers and/or two external
USB-OTG-capable transceivers.
Several different types of external transceiver signaling are supported.
Signaling between the OMAP5912 USB controller and the external USB
USB OTG Controller
Universal Serial Bus (USB) 243