Honored Contributor
Honored ContributorNo - you don't necessarily need to manage this 'outside' the Nios core. You could chose to manage any 'metastability' in software in a similar way to how you might manage button bounce.
In practice, when your software request the port value it will be given a value, '0' or '1'. If this is at a point when the port level is changing you will still be given a '0' or '1'. Whether either is right is debatable since the logic level is changing. However, the point is that the software will report a genuine value - '0' or '1'. Should you request the port value again immediately, the level will have settled and the new value may or may not have changed. Managing this outside the Nios core is perfectly fine too. It's down to the designer to design any interface on or off the device appropriately to the requirements of that interface. Cheers, Alex
