xMaster Gabriel, [img] outsidetrains.com/smile/bowing.gif " />
In an ATTiny, it took less than an hour to made the ADC read a voltage, including discovering I was reading the wrong pin. On xMega, it's been 4 days so far. "Doesn't anybody know how to make this work?" I was poking around with my dear Gabotron, when I realized, "Here's an xMega using it's ADC! xMaster Gabriel must know how to make them work!"
 
So, how do you make these blame things work? If I try it single ended, it always tells me 0xfff (full scale). if I try it double ended, it always tells me -2048 (negative full scale).
It's an xMega192D3
Pin B4 is 0.72v
The AVCC is 3.3v with a .1 uF cap to ground just like all the other vcc pins. 
I've programmed Port B like this:

Hi Torby!
I took a look at the register setup but I can't see what's wrong, Try this:
Change:
//PORTB.PIN4CTRL = (3<<3);/\r\n/to:/\r\n/PORTB.PIN4CTRL = 0x07; // Digital Input Disable on pin PB4

Well, yours is the first suggestion that makes sense, and I've tried many. The ADCA.CH0RES still says -2048.

I got it working, but it would go haywire when I changed the mux to sample something else. The guy at Atmel suggested sampling twice when I switched mux.
 

Oh yes. In case anybody is reading and trying to make the adc work, I posted my results at www.barefootelectronics.com/xMegaADC.aspx