[awjlogan]

My feeling about programmable IOs is they’re fun, but not the right choice for commodity high speed interfaces like USB. You obviously can make them work, but they’re large compared to what you would need for a dedicated unit. The DVI over PIO is a good example: showed something interesting (and that’s great!) but not widely useful. Also, a lot of protocols, even slow ones, have failure and edge cases that would need to be covered. Not to mention the physical characteristics, like you’ve said for high speed USB.

[MayeulC]

This is true, but only relevant if you order enough units (>100 k? Depending on price & margin of course) to customize your die. Otherwise, you have to find a chip with the I/Os that you want, all the rest being equal. Good luck with that if you need something specific (8 UARTs for instance) or obscure.