Based on my reading of the data sheet, it seems the DMA in the UC3 is not very flexible. It seems to only be usable for transfers to/from specific peripherals.
Can the U3C DMA be used to do memory to memory transfers?
Could the DMA be used to output data onto port pins?
For example, I have used another micro in the past where you could set a timer as the DMA trigger and set the destination address as the port output register.
It looks like both of the above will be possible with the new xmega.
I have an application in mind where I want to be able to do this, so I hope I am just interpreting the UC3 data sheet incorrectly.