Texas Instruments OMAP5912 Reference Manual page 1536

USB OTG Controller
4.4 Selecting and Configuring USB Connectivity
4.4.1 Select Desired USB Functionality
244 Universal Serial Bus (USB)
transceiver for monitoring and controlling the differential USB signal can be via
a 6-wire, 4-wire, or 3-wire signaling interface, with two or more additional
control signals provided either by additional signals or via an I
transceivers can support the 6-wire, 4-wire, and/or 3-wire basic signaling but
generally provide an interrupt output and an I
and status reporting required by OTG functionality.
The process of selecting desired USB connectivity and configuring
OMAP5912 for that connectivity can be done using the steps listed below.
Choose the desired USB functionality. OMAP5912 can bring up to three USB
ports to device pins. Options include:
-
One USB device port
-
One USB OTG port
-
Up to three USB host ports
Choose a maximum of three of the above. It is not possible to configure both
a USB device port and a USB OTG port, because the USB OTG port must use
the single USB device controller. Similarly, a USB OTG port also makes use
of one of the three USB host controller ports. Some possible configurations
are:
-
One USB device port
-
One OTG port and one host port
-
Two host ports and one USB device port
Some illegal combinations are:
-
One USB device port and one OTG port (only one USB device controller
is available; it can be used as part of the OTG functionality or it can be used
as a standard USB device port, but not both simultaneously)
-
One OTG port and three host ports (violates the maximum of three USB
ports brought to OMAP5912 pins; also violates the limitation of three
available host ports where one is used by OTG)
-
Three host ports and one USB device port (violates the maximum of three
USB ports brought to OMAP5912 pins)
2
C link. OTG
2
C link for the additional control
SPRU761A