maemo.org - Talk - View Single Post - N900 will not allow USB OTG!

	joerg_rw	2010-03-20 , 15:36
	Posts: 2,222 \| Thanked: 12,651 times \| Joined on Mar 2010 @ SOL 3	#635

Originally Posted by sarahn

joerg_rw, are we certain thats the rx51 and not the rx71? It seems rather odd to have power available and connect id to twl4030 and not support usb host.

The PHY can't supply power but it can enable an external charge pump. I hadn't seriously considered and put the probability of that doing anything rather low, that but it's easy to try.

Well, all the pages read "Version: 2.0 | 07.10.2009 | N900/RX-51 | Board version: 2JH_21a "

It's quite possible the board rev of MP devices is a little different, though 2009-10-07 (if that's the correct way to read this) on schematics makes me think it isn't completely different from what shipped 6 weeks later.

Anyway for switching the port to hostmode it's not a big thing if ID is connected to PHY or anything else, and also it doesn't matter you have to enable VBUS via register config. You need to disable bat charging via USB same time you're enabling VBUS charge pump (this is no perpetuum mobile ;-). All the issues arising from OTG protocol complexity are neglegtable for a simple manually enabled host mode.

jOERG