Atmel Xplained Evaluation Board AT32UC3A3-XPLD AT32UC3A3-XPLD Data Sheet

Product codes
AT32UC3A3-XPLD
Page of 1021
747
32072H–AVR32–10/2012
AT32UC3A3
27.8.4
USB Pipe/Endpoint n FIFO Data Register (USBFIFOnDATA)
The application has access to the physical DPRAM reserved for the Endpoint/Pipe through a
64KB virtual address space. The application can access anywhere in the virtual 64KB segment
(linearly or fixedly) as the DPRAM Fifo address increment is fully handled by hardware. Byte,
half-word and word access are supported. Data should be access in a big-endian way.
For instance, if the application wants to write into the Endpoint/Pipe3, it can access anywhere in
the USBFIFO3DATA HSB segment address. i.e : an access to the 0x30000 offset, is strictly
equivalent to an access to the 0x3FFFC offset.
Note that the virtual address space size (64KB) has nothing to do with the Endpoint/Pipe size.
Disabling the USBB (by writing a zero to the USBE bit) does not reset the DPRAM.