Is it possible to use the AT32UC3C family with two different voltages for the VDDIO pins? The datasheet mentions two supply ranges (5V or 3.3V nominal) for VDDIO1, VDDIO2 and VDDIO3 in different places so that one might think it's possible to run some of the VDDIOs off 3.3V and some off 5V. However, in one place the datasheet states that "the VDDIO pins should be connected together". "Should" is not "must", though. I measured the resistance of an unused chip's pins and between the different ground pins I get about 4Î©, but between the various VDDIO (or VDDANA) I get values above 1.6MÎ©, suggesting that they're not connected.
Has anyone ever tried this?
I found only one relevant topic for this, but that OP was asking about 1.8V, which is not a valid IO voltage for the AT32UC3C.