I have a batch of XMega128A1s that all exhibit the same behavior: PORTB pins 4-7, JTAG port (are all pulled high to 0.7V, diode drop from somewhere?), even when being held under reset with no peripherals attached.
In addition, the pins are not configurable in code. I also tried to set the ACB_CTRLA bit, but that does nothing.
I have older XMega128A1s that do not exhibit this behavior.
Was there a silicon change? I can't find anything applicable in the errata.