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Living in:

  • Germany

Interested in:

  • implementing some rendering stuff (for some unknown reason/purpose)
  • using gpgp and/or implementing encryption/key-signing for e.g. sms

Can be contacted by email h e n r i k @ z i m m e r . t o

See my FreeRunner-Experience-Blog-a-la-Amateur (btw. in German)

Usb Power

To be able to have a keyboard (i.e. FR acting as a USB host) connected to the FreeRunner and charging the FreeRunner (FR acting as a device) at the same time I modified my USB Hub

  • Brand: Equip
  • Type: 4 Port USB2.0 aluminum

to also supply power to the upstream port of the hub.

Supposedly this is done by shorting a certain diode in the hub, which enables current to reach the upstream port (USB_host). Since I was unable to locate any diode on my hub I decided to do as mentioned here Chockerblockablog, that is to simply connect the +5V (pin 1) from one of the downstream ports to pin 1 of the upstream port (connected to the FreeRunner). [For all the hubs I've bought here in Taiwan, plugging an external power supply into their coaxial port also supplies 5V to the Mini 5 pin socket, as well of course to the 4 USB A sockets. Jidanni 02:13, 26 November 2008 (UTC)] Also the FreeRunner needs to be told to 1. Be a host, 2. to charge (faster than 100mA default). These are the steps (as I did them, no warranty...)

  • Modify USB Hub by bypassing diode with a jumper OR connect pin 1 (+5V) from downstream port to pin 1 of the upstream port
  • Tell FR to act as a USB Host
echo "host" > /sys/devices/platform/s3c2410-ohci/usb_mode
  • Tell FR to enable charging
echo "0" > /sys/devices/platform/neo1973-pm-host.0/hostmode
  • The FR is now charging with 100mA
cat /sys/class/i2c-adapter/i2c-0/0-0073/usb_curlim

outputs "100mA"

echo 500 > /sys/class/i2c-adapter/i2c-0/0-0073/force_usb_limit_dangerous 
  • DONE! Now the FR is charging with
cat /sys/class/i2c-adapter/i2c-0/0-0073/usb_curlim

"500mA" and now a Usb keyboard, mouse etc. can be used while charging!

NOTE: to actually attach the Usb Hub to the FreeRunner, I used a USB gender changer (here are some (other) suggestions Specialized_USB_cables))

NOTE2: Another (solder-less) option is described here no-solder-usb-host-method (for a N770, but who cares)

NOTE3: Also, wikipedia is your USB-friend

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