3.3V vs 5.0V IO on Arduino Giga

[stitech]

@jim-p

How do you know what will be connected

In post #1 OP mentions TTL ICs to be connected to Arduino boards.

@jim-p

3.3V, and you should not apply voltages higher than that to the GPIO pins

This is a general advice, and a good one. But, in some cases, if you know what you’re doing, more is possible. This begins with understanding — understanding — the relevant datasheets. And if you think you know what you’re doing, you’re taking a risk of damaging your circuit.

[jim-p]

@stitech

And if you think you know what you’re doing, you’re taking a risk of damaging your circuit.

Can't agree more. I think you have made my point.

[stitech]

@jim-p

Can't agree more. I think you have made my point.

My point was: sometimes more is possible — for people that have knowledge and are willing to spend the time to study the datasheets.