Occasional Contributor
Regular ContributorIf you have control of what parts are attached on each I/O line adding any kind of 'protection' is really not necessary.
That being said, I have several commercial FPGA development boards that have FPGA I/O pins that attach to user connectors.
Some of these boards have just a series resistor in the range of 22 to 47 ohms.
Others also have diode clamps to VCC and GND on each I/O line.
If you can't control what is connected this extra circuitry helps a bit (but it is not foolproof).
Occasional ContributorThank you for your answer. In general what I mean is like connection between FPGA and Microcontroller. I suppose, that if both are push-pull, both configured (by accident) as outputs, first is high, second is low - that might be not fun for both of these ICs.
