I know this sounds a bit odd, but here it goes:
- On PB6, which is an ADC input as well (and that is how I intend to use it) I get around 0,893 Volts in all cases, except when I don't start ADCs, set is an output and set level to 0.
- When I use it as ADC6
- When I use it as a digital input in modes Totem poll, with or without Pull up and Pull down
- When I set it as a digital output with High level
- When I erase the firmware of the device and reset it
Some additional info:
- ADC reading seem to correspond to that signal, I get about 3800 when using Vref 1V, single-ended (and considering the offset).
- I use PDI, not JTAG (this pin is the JTAG TCK, but not in this case) and that's where I get the power from.
- I've tested on several devices, so I rule out the possibility for a defect in the MCU.
The hardware dev department claims, that there is nothing connected to that pin, it goes to ground through 10K resistor. The circuit to that input pin is complicated, but supposingly unconnected on the test pcbs for firmware dev.