I have working code for the dataflash on the xplain (AT45DB642D). I’ve done some minimal read write tests, but i /think/ it works… caveat emptor. Reading and writing to the 2 buffers, as well as direct flash access has been tested (writing buffer->flash with both auto and explicit erase, reading in high and low speed stream mode). I haven’t implemented all of the possible ways to access the device, just the major ones. Only page at a time erase, no security/locking support. Support for entering and resuming from low power mode is implemented.

Unfortunately, the spi interface on the ATXMEGA128A1 only goes up to 16 MHz, so I can’t test the flash at full speed, as it is supposed to work at up to 66 MHz or so. Takes a couple minutes to do a full read/write/scrub byte-by-byte test, not too bad. Might do some datalogging stuff soon.

Next up: the sdram!

The code:
dataflash.cc
dataflash.hpp

Note that the code uses some other SPI and initialization code I wrote, I might post all the code together later, once more of it is written. 

Finally got around to working on my xplain, will be posting code to use the flash and sdram soon.  This is a really nice little board – 32 MHz ATXMEGA128A1, 8 MB flash, 8 MB sdram.