I am submitting a chip to TSMC for fabrication in a couple of days. Using their I/O's is turning out to be a bit complicated for my design aince I have multiple dedicated supplies. Is it ok to connect directly to the pads and skip the I/O's altogether? Do i need to use a Schmidtt trigger at the input pad of all the digital inputs?
If you don't need drive strength, noise rejection or ESD
protection, then you will be just fine. Heh.
Schmitts help your inputs not chatter when you feed
them signals with slow edge rates and noise on them.
You know, like what comes out the other end of a
probe harness or a hastily done bench test wireball.
I understand you are talking about TSMC I/O structures. If you have little more time you could design your own I/O.
Schmitt - no you do not need to have it but it is very good idea.
If you have multiple power supplies you should have ESD protection between them - unless it is a test chip and you are aware of ESD risks.