The AU-UB9520 USB 2.0 OnTheGo (OTG) AMBA Subsystem provides a USB 2.0 OnTheGo
(OTG) peripheral subsystem for AMBA based SOCs. It contains a USB 2.0 Device and Host
Controller that connects seamlessly to the AMBA AHB Bus. As a dual mode USB 2.0
Controller, its intended use is:
- in USB hosts and devices
- as a host with several (up to eight) device ports
- in device mode as a device or hub
- where more fully featured USB drivers (software) are required

USB 2.0 Device
• Ten endpoints:
- EP0- control endpoint, accepts SETUP, IN, and OUT control transactions
- EP1- interrupt endpoint, accepts IN and OUT interrupt transactions
- EP2, EP4, EP6, EP8- IN endpoints, IN bulk and isochronous transactions
- EP3, EP5, EP7, EP9- OUT endpoints, OUT bulk and isochronous transactions
• Includes control pipe registers and USB Descriptor RAMs at EP0
• USB command execution in EP0
• Can function as a hub that enables peer to peer USB communication among dual
mode devices attached to its ports
USB 2.0 Host Controller
• Initiates all required USB high speed and full speed transaction types
• Up to eight downstream ports
• UHCI (full speed operation) and EHCI (high speed operation) support
• UHCI and EHCI list and transaction descriptor processing in conjunction with DMA
DMA/AMBA Interface
• AMBA AHB Bus interface
• 12 channel DMA Engine
- USB data from/to each endpoint to/from the USB 2.0 Device block
- USB data from/to host data buffers to/from the USB 2.0 Host Controller
• Physical DMA addresses
• Programmable DMA starting address, transfer count, transaction size, transfer size
• Locked DMA operation optional (software programmable)
• Direct software writes or information extracted from descriptors in memory, to
program DMA control information
• 3 AMBA Bus master interfaces- DMA transmit data, DMA receive data, non-DMA
• AMBA Bus slave interface for register reads and writes
• Interrupts- device mode and host mode