Easy USB Host Hub setup
I figured out a pretty easy way to connect USB peripherals using a powered USB hub.
What you need: An externally powered USB hub with cable for connecting it to a PC. A spare USB cable like the one that came with the 770. It should be a USB A female on one end and a mini USB B 5 pin on the other. See http://www.taltech.com/TALtech_web/support/pins2.html for details on types of USB connectors.
Overview: The 770 host mode is limited by the fact that not only does it not provide power to the port, the 770 USB chipset requires power externally to work (I might be wrong about that, I'll test that later). So the trick is to take a powered USB hub, steal power from one of the output ports and feed that power back into the 770 and the hub input.
Step 1. The hardest part. You are going to make a 3 headed USB cable. One head plugs into the input of your USB hub (usually a USB type B connection) Another head is a USB type A that pulls power from one of the hub outputs. The third head plugs into your Nokia 770. (Why pull power from USB hub into the Nokia? Without this there'd be no need for the freaky cable...)
I'll put a schematic up here when I get home and get to a paint app but for now you should be able to do everything based off of the wire colors. I've cut open more than a couple of USB cables and all I have seen are set up as follows:
Signal Name | Wire Color |
---|---|
+5V | Red |
ground | Black |
+Data | Green |
-Data | White |
Cut your USB cables (read all the way through first and think about cable layout before you cut). You should have 4 usb heads, two A males, one mini B 5 pin male, and whatever mates to your hub input (usually a B Male). Discard one of your A males. On the other A male you are only interested in power, so ignore the green and white wires on that one. Now solder all three red wires together. And solder all three black wires together.
Now connect the data lines from the other two heads (Mini USB B 5 ping and hub input).
The net result is the data lines (green and white wires) from the Nokia should be connected to the data lines for the hub input. The power lines for all three head should connect up (all three red wires joined, all three black wires joined). The green and white wires from the USB A male are not used.
Step 2.
Use a "regular" USB cable and your host PC to enable host mode. Linux instructions:
* disconnect your 770 and power it down (not sleep, full shutdown)
* on your host box (as root): ./flasher --enable-usb-host-mode
You should get a message saying it is now in host mode.
STANDARD DISCLAIMERS APPLY Do this at your own risk, I am not responsible for unclear instructions or reversed polarity. You will damage your 770 if you have the polarity backwards.
Plug the powered hub into the wall. Hook the cables up. The easiest test is to plug in a USB keyboard (no drivers required). It should just work.
This is the rough instructions, this did not turn out to be as easy as I thought. I'll follow up tonight or tomorrow with schematics and clearer text.