Public Version
High-Speed USB Host Subsystem
www.ti.com
22.2.4 High-Speed USB Host Subsystem Functional Description
This section describes the functionality of the high-speed USB host subsystem by describing the
high-speed USB host controller and the USBTLL module.
22.2.4.1 High-Speed USB Host Controller Functionality
The full details of the standard OHCI and EHCI host controller APIs (implemented by the current module)
are not repeated here. For more information, see the following public specifications:
•
Open Host Controller Interface (OHCI) specification for USB Release 1.0a
•
Enhanced Host Controller Interface (EHCI) specification for USB Release 1.0
22.2.4.1.1 High-Speed USB Host Controller Architecture
shows an overview of the high-speed USB host controller internal architecture: It contains
two independent, 3-port host controllers that operate in parallel: EHCI and OHCI. Each of the three
external ports is owned by exactly one of the controllers at any point in time. Each port can work in
several modes:
•
When the port is owned by the OHCI (full-speed) host controller, the serial 6-pin interface mode is
used.
•
When the port is owned by the EHCI (high-speed) host controller, either the ULPI or the UTMI modes
are used.
The L4-Core interconnect is used to configure the two controllers, as well as a general, TI-specific register
bank. The L3 interconnect merges and arbitrates between the transactions generated by the controller
respective DMA engines.
3270
High-Speed USB Host Subsystem and High-Speed USB OTG Controller
SWPU177N – December 2009 – Revised November 2010
Copyright © 2009–2010, Texas Instruments Incorporated