The only difference:

The software solution oscillate with the sampling freqency and the CPLD solution oscillate also, but with the real oscillation frequency.

So no difference on both from the users view.

If you want to suppress it, you need additional software, e.g. accept a value only, if it was the same during a certain time.

Errors above 1 can only happen, if more then one state changing occur during the sample interval, e.g. 1-2 or 0-3. But then it is your fault since you have designed the sampling time to slow for your application.


Peter