Shields: official Arduino Revision 3 layout

The Due will continue to work with all Arduino shields — add-on boards and circuitry like motion sensors and LED light arrays — that conform to the official Arduino Revision 3 layout. However, the Due operates at 3.3V whereas AVR-based Arduinos operate at 5V, meaning some third-party shields that don’t follow the R3 specs to the letter may not be compatible, depending on their voltages.
Microcontroller Maniacs Rejoice: Arduino Finally Releases the 32-Bit Due | WIRED

I looked all over the arduino site and didn't find this shield specification. The reference section is only about the language. The pages for official Arduino shields don't seem to mention, far less link to, these specifications.

Does anyone know where they are? If it is important to comply with them, shouldn't they at least be discoverable?

In general the Arduino documentation is pretty woeful, such a spec may exist but I've never seen it. As with everything else you have to grab the schematics and PCB files and even look in the code.

I really think the docs need a lot of work but who's going to do it? Nobody gets paid for doing this stuff and those with the knowledge are probably too busy doing other things.


Rob

Well, that would explain why some "third-party shields that don’t follow the R3 specs to the letter" might exist, then.

Maybe.


Rob

Nantonos:
Well, that would explain why some "third-party shields that don’t follow the R3 specs to the letter" might exist, then.

Heck, I would like to see just one example of a 3rd party shield manufacture that does follow the spec such that it can work with both 5v and 3.3v controller boards, just one in production shipping 3rd party example would surprise me to no end.

Lefty

Sorry to revive this thread, but I asked the same question in the Due forum on Friday and did not get any reply.

Is there really no spec for R3 compatible Shields? (I mean, this would certainly explain all the new shields that only work on the Uno...)

Is there a list of R3 compatible Shields at least? (Forget shieldlist.org)

p.

Is there a list of shields that have been designed SINCE the R3 introduction?