Yeah, but it would also allow you to tell the firmware to sink all it wants in the case of crazy USB2 mobos like Gigabyte and their 1.5+ Amp USB2 ports.
[9:14:59 PM] mkawa:
http://www.usb.org/developers/devclass_docs/BCv1.2_011912.zip[9:15:06 PM] mkawa: this is apparently the new high current spec
[9:15:48 PM] mkawa: although i will note that at the very least usb3 gives you 900ma @ 5v and you could actually generate a bunch of current by sending dummy data back and forth
[9:16:37 PM] mkawa: transmission logic level is variable for some reason.. but it goes up quite a bit when you saturate the bus
[9:16:51 PM] mkawa: like 3.6v
[9:17:43 PM] mkawa: so you can request 900ma on the 5v rail and then have a bunch of parasitic draw that's actually directly packet power to a fet somewhere..
[9:22:35 PM] mkawa: there's a forced delay of 200ms between data mode (900ma max) and charging mode (1.5A)
[9:22:52 PM] mkawa: but you can switch modes by logic request, without physical detection
the radio edit here is that you don't need a second port to pull that current. you just need to switch modes. the crazy gigabyte ports are following spec for the most part. all they're doing is extending the "charging port" spec to usb2 devices (and the specification is actually quite vague about whether usb2 devices are allowed to do it. they can if they self-identify as "superspeed devices" and the ports implement some or all of the "superspeed" spec.)
i think asus and giga do have some insane spec breaking ports now, but they're way more than 1.5A. they're like 2A+, and i think they actually ground out all the non-power rail pins when they deliver that current. the usb3 spec actually requires that all ports be fused at 5A
a couple more things:
1) charlieplexing
2) yes that austrian MCU is incredibly pin-efficient. it's quite pissy that MOQ is so high on it from the manufacturer, and it's not available via the usual sources (yet?)
