N900 Hardware isp1707
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--[[User:speedevil|speedevil]] 21:21, 11 January 2010 (UTC) | --[[User:speedevil|speedevil]] 21:21, 11 January 2010 (UTC) | ||
However - this is a challenging rework job, even for those experienced with SMD soldering, and of course will void the warranty! | However - this is a challenging rework job, even for those experienced with SMD soldering, and of course will void the warranty! | ||
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| + | A possibly related errata is detailed at 3.1.3 in [http://focus.ti.com/lit/er/sprz278d/sprz278d.pdf this document] - this, and other erratas may or may not cause issues with implementing host mode. | ||
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[[Category:N900_Hardware]] | [[Category:N900_Hardware]] | ||
Revision as of 18:47, 9 March 2010
The NXP isp1707 is used as the USB PHY chip. [1]. This rights to this part have been bought by ST-Ericson and some information is available in a brief marketing sheet.
There is no published datasheet for this chip. It may be available under another name.
One unnamed source claimed " It is not connected in a way which the direction of the USB port can be reversed.
This means that host mode is impossible without hardware modifications.
Reportedly connecting pin D3 (ID) to D2 (GND) of the chip will allow direction to be switched.
"
This however may be incorrect - it seems on a reading of similar device datasheets that yes, the ID pin is used on hardware that supports it to switch between host and device mode.
But, importantly, the ID pin does nothing directly to the state of the chip. It simply informs the CPU of the state of the ID pin, and leaves the driver to properly configure the chip.
So, if the kernel can be altered to ignore this pin - which should be trivial if there is host mode support for the chip in the kernel - then host mode works.
--speedevil 21:21, 11 January 2010 (UTC) However - this is a challenging rework job, even for those experienced with SMD soldering, and of course will void the warranty!
A possibly related errata is detailed at 3.1.3 in this document - this, and other erratas may or may not cause issues with implementing host mode.