Probably because of the super huge errata list?
Or the lack of interest in complicating the software or the team simply doesnt still have lots of code for Xmega to copy to make a super duper core, like they made with the atmega....
The errata list shrink form Rev to Rev.
You need a hardware in order to write software for it.
There were also the initial availability problems. Xmegas were announced, but you couldn't actually buy them anywhere.
And the "not 5v" issues.
I have a partially complete xmega arduino design. I'm not quite sure what it is good for, other than running twice as fast as a normal arduino (which may be a problem in itself. The Maple and chipKit designs went to 4-layer PCBs...)
I'm asking in 2011 where you can get XMEGA's everywhere.
A lot of Sensors on existing shields only work with 3.3 V and also for example
- XBee or
- w5100 Ethernet Shield
- or GSM Shield
do not work with 5V but with 3.3V so you need additional efforts to get 3.3V on shields at the moment.
It is not just twice as fast.It is also DMA, Event System, several UARTS, I2C and SPI interfaces.
So if somebody have a Xmega Arduino variant I wil buy it.