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

blue_led	2010-04-07 , 18:19
Posts: 306 \| Thanked: 566 times \| Joined on Jan 2010 @ Romania	#672

Originally Posted by shadowjk

After reading bq24150 sheet last week I thought a bq24150 not under software control would start charging if there's power on vbus and OTG goes to 1.

i think you are wrong

OTG = Boost mode enable control or input current limiting selection pin. When OTG is in active status,
bq24150/1 is forced to operate in boost mode. It has higher priority over I2C control and can be OTG D4 I disabled through control register. The logic voltage level at OTG active status can also be controlled.
At POR, the OTG pin is default to be used as the input current limiting selection pin. When OTG = High, Iin – limit = 500mA and when OTG = Low, Iin – limit = 100mA, see the Control Register for details.

so
otg = chgr_det = 1 >> boost on charge , stupid
otg = chgr_det = 0 >> no power , no boost , no host ( 3N

)
how hell actually charging is made ? probably isp1707 is disabled by software and through 100k ( R4281 ) resistor otg=low resulting charging is enabled
really, really stupid choice. quick and dirty and overall wrong

Last edited by blue_led; 2010-04-07 at 18:35.

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