Nook Tablet is known to have "extended USB" connector with bunch of extra pins in addition to standard microUSB's 5, and it seems it is the same (at least mechanically) as on Nook Color. Unfortunately, I wasn't able more specific information about the connect than this thread
, and Novaports teardown picture
which clearly (well, blurily) shows 17 pins, half of them apparently connected to something more interesting than power and ground.
So, is there updated information on this matter? I know folks here made hardware mods while cracking open the Tablet, so I don't believe it could escape their scrutiny. I don't suppose there's UART in there, but well, who knows, maybe charging LED is controlled by full-fledged GPIO for example ;)