I have not been able to find the input tolerance on I/O pins, especially on the Input pins. If I apply a voltage 3.6v (3.3v +0.3) on an input will it be dangerous or is it ok ?
Does somebody have a technical datasheet?
There are no formal published data, but the following summarises what I have been able to discover. Electrical Specifications of GPIO
I would NOT apply 3.6V to a GPIO pin, but if the voltage does not exceed Vcc + diode voltage (~0.7V) damage is unlikely. I would use a serial resistor in any event.
If you know the voltage may be excessive use a resistive divider. Any voltage >2.0V will be HIGH (actually the threshold is more like 1.3V)