Thread: N900 will not allow USB OTG!
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javispedro is offline javispedro
2010-05-20 , 19:20
Posts: 2,355 | Thanked: 5,249 times | Joined on Jan 2009 @ Barcelona
#928
Originally Posted by joerg_rw View Post
We need to put "echo host >mode" to work, we need to switch PHY chip to host config which is 2* pulldown R.
Fully agreed. What is needed:
  1. Set up a special global variable that is asserted after otg_set_host
  2. When this global variable is asserted, disable all power saving stuff on the PHY
  3. Also make otg_set_host configure 1707 appropiately via Nokia's MUSB ULPI helper functions. Also ensure you power it before configuring.
  4. Ensure the 1707 remains configured (to check if item 2 was done properly)
What is missing:
  • List the places where the 1707 PHY is being reset, powered down, reconfigured..
  • Understand why the way the 1707 is currently configured doesn't match what we'd expect for normal peripheral operation.
  • And of course, what would be the correct 1707 configuration for host mode (might not be what the datasheet says, as per the above).

Note that I'm not sure what I'm talking about when I say "powered down." It might be low power ulpi protocol, it might be really powered down (but 1707 is connected to vbat?), ...
Last edited by javispedro; 2010-05-20 at 19:23.
 

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