gpio voltages

[MarkHaysHarris777]

Never touch more than 3v3 to any gpio pad ; ever !   (blue smoke, instant SoC failure)

Please see the SoC datasheet link provided.

Please see the SoC User Manual link provided.

So say I have a ADC0832, its a 5V piece, it has a Digital out at 5V, whats the best way to read the output?  Resistor in series?  How big?

What about the inputs to the ADC0832, they register voltages over 2 volts as a 1, can I hook the outputs to the ADC0832's inputs??
Thanks!

The correct way to mix 5v and 3v3 logic is to use a level-shifter;  the one in the link is a four channel, but there are also larger ones-- the eight channel is popular.

Essentially the shifter-board has a high voltage reference, as well a low voltage reference.  One side of the board has the high voltage pins, and the other side of the board has the low voltage pins.  

It is ill advised to use a voltage divider resistor network, nor a resistor in series;  especially for ADC and DAC work.  Use proper level shifters always.