Hi Vinny,
Thank you for such a detailed set of answers!
In response to your points:
We will just make a super short connector between the daughterboard and J1. I did like the elegance of a single board that snapped on and did everything we wanted but this really won't add much to the footprint. We are running 12v passive power over ethernet so we will make sure that per the docs there is a nice supply of 5v 6a for the j1 port. Yep just making sure, this will be shunted strait into a usb-to-ethernet setup (based on the rtl8153-cg chip), depending on how annoying the GPIO stuff might be we did think about simply putting a tiny powered usb hub onto the daughterboard and breaking out a usb connection in order to do those tasks (a little more effort to implement but more flexibility) Ooof that is a bit of a minefield isn't it? The BLSPs do look to be the best choice if we go with the GPIO idea. In light of this it might not be that bad an idea to go with the USB microhub idea, that way it would not be hard to implement another discreet microcontroller to deal with any realtime/gpio tasks and simply package that up into a nice neat message to pass upstream.We will do a bit of planning and let you know where we got to.
Regards,
Thomas