To avoid latch-up or malfunctions the I/O pins should not be externally driven while the I/O supply is OFF.
At what current do you consider an I/O pin to be driven?
Will an external 100k resistor, pulled up to external 3.3V, drive the I/O pin?
Hello Claes-Henry Aronsson,
There is not a current currently specified as acceptable. As you mention the datasheet states that no I/O pin should be externally driven why the I/O supply is OFF.
I wouldn’t recommend using an external 3.3v in order to drive the I/O pin but rather using the I/O supply rail to drive it.