Just got hold of an ATXMEGA32A4U-AU as I want to run the High Res. Extension at x8.
Problem is that the STK600 reports the chip as an ATXMEGA32A4 not AU. The chip works fine when programmed as an 'A' at x4 high res extension, but when asked to do x8, it does not work. Thus the chip ID bytes report it is not an AU but an A and it works like an A.
As the chip is sold by a reputable distributor and marked as an ATXMEGA32A4U-AU, has anyone got any explanation?