GPIO: input/output VOltage

[herter]

Hello,

I need you to confirm me some details please.
Indeed, I wonder if the GPIOs can provide and receive a voltage of 5 V or just 3.3V.
Moreover, It seems that there are no analog inputs. I'm wrong?
Thanks for your replies.
Regards

[JohnS]

Not 5V.

John

[dave-at-axon]

As per JohnS's comment, a search of the documentation shows no reference to 5V tolerance so assume 3.3V or whatever the GPIO power pin is configured for. The A20 board is wired for 3.3V as per the schematic.

If you need a simple level shifter, TI do a number of devices or if your design is simple and only a few lines, the FET shifter shown here works well with non-highspeed designs.

https://www.sparkfun.com/products/11978

As an aside, if you ever need isolated level shifting, check out the ADUM range of devices from Analog Devices.

[herter]

Hello,

First of all, thank you for your answers.
Then, I prefer to step down the 5 V signal to 3.3 V by using simply a voltage divider (as the sparkfun product) and a follower amplifier, to avoid any perturbation.
Indeed, the examples on the sparkfun website are made with serial SPI/I2C which often use an open collector/drain output.