Sorry for what may be a noob question, but I've literally had this problem dropped in my lap.
We have an ATXMega8E5 hanging off an IMX6 host CPU that using the XMEGA for its TWI and QDEC. That's all running fine, but now the task is to read the user_signature row from the XMEGA flash from the IMX6 and I don't know how to access the flash memory. Is there an app note or the like that can show me? I don't mind reading, just don't know where to start looking. I had the XDF project that set up the TWI and QDEC, so I can add the extra stuff there to expose the flash address space.