Usb Host Cable Problem/questions


GameGod

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Nov 26, 2006
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Hey guys,

I've built myself a USB host cable, but it doesn't work, and I'm trying to sort out why.

When I turn on USB host and hid, dmesg spits out:
usb.c: new USB device <NULL>-1, assigned address 5
usb.c: USB device not accepting new address=5 (error=-110)
(among other USB related messages)

The problem is either with my setup or with my soldering. Right now I've got the E810 USB cable (or something) modded with a USB host connector on the other end, with all 4 USB wires hooked up properly on both ends. I then have a _powered_ USB hub plugged into my host cable, which should allow me to use non-3.3v USB devices.
Does that work? (ie. Does plugging a powered hub into a GP2X host cable work?)

If that should work, then I might try shortening my cable. Right now the cable is about 14 cm long (about 19 cm from end-to-end of each connector)...

If anyone could point me in the right direction, I'd appreciate it!

Thanks!
 
GameGod posted on Feb 24 2007 at 06:05 PM said:
The problem is either with my setup or with my soldering. Right now I've got the E810 USB cable (or something) modded with a USB host connector on the other end, with all 4 USB wires hooked up properly on both ends. I then have a _powered_ USB hub plugged into my host cable, which should allow me to use non-3.3v USB devices.
Does that work? (ie. Does plugging a powered hub into a GP2X host cable work?)

If that should work, then I might try shortening my cable. Right now the cable is about 14 cm long (about 19 cm from end-to-end of each connector)...

If anyone could point me in the right direction, I'd appreciate it!

Thanks!
Go see my instructions if you haven't already:

http://www.gp32x.de/board/index.php?showtopic=34309

And I am assuming you have constructed this circuit?

http://wiki.gp2x.org/wiki/Image:Bob_usb_filter.png

Now, I can help you with any questions you might have, cable length shouldn't be a problem, my cable is as long as you see in my thread and it worked just fine for USB 1.1, AKA slow if I tried copying from one USB device to another USB device. But it was fast enough when running a PSX ISO or copying to NAND/SD.

I have no idea if a your powered hub needs a power signal or needs more than 3.3volts, but since you are actually getting something that is a good sign, it is possible your communication lines look like this: http://wiki.gp2x.org/wiki/Image:USB_Scope.png If you haven't terminated the com lines with some kind of filter circuit they will look like that, and the GP2X can't understand them if they aren't clean digital signals with a straight clean line at top and bottom and square corners. AKA: --_--_--_--_--_--_

That pic was sourced from this page from my sig: http://wiki.gp2x.org/wiki/USB_Host
 
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Thanks for the reply nubie!

Someone on #gp2xdev told me you don't need the USB filter circuit on MK2s - does anyone know about that?
In the worst case, I can always build the filter circuit.

I've already found and fixed one problem with my cable, which was that the outside of the USB end wasn't grounded properly. It's still not functional though, so I'm going to check my solder joints for the two USB data lines.

If I hook up my scope to those USB lines, how do I know that the GP2X is actually going to be signalling down them? (like, is it constantly probing the USB H+/H- or something?)

Thanks!
 
GameGod posted on Feb 25 2007 at 05:48 PM said:
Thanks for the reply nubie!

Someone on #gp2xdev told me you don't need the USB filter circuit on MK2s - does anyone know about that?
In the worst case, I can always build the filter circuit.

I've already found and fixed one problem with my cable, which was that the outside of the USB end wasn't grounded properly. It's still not functional though, so I'm going to check my solder joints for the two USB data lines.

I built my circuit for my MKII, I never heard that it was unnecessary, maybe the hubs they used could function without it.


If I hook up my scope to those USB lines, how do I know that the GP2X is actually going to be signalling down them? (like, is it constantly probing the USB H+/H- or something?)

Thanks!
Good question, on boot-up it will probe (wish I had a scope <_< ), so I would attach the scope and then boot it and watch the scope, maybe grab a capture if you can, you will know if it is terminated real quick.

Come to think of it I do have winscope for a soundcard input, it will only take ~2 volts, but if I use a resistor down to that voltage I can see frequency and how clean the signal is. I used it to view the PWM output of my R/C car controller, then I bridged the 2-channel transmitter and got 4 outputs :), ah fun.
 
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I built the USB filter circuit, and my USB host port seems to be working now! :)

(So I now have "hacked cable with USB filter circuit"->"usb hub"->"usb devices"...)

Thanks nubie!
 
Would you be willing to put some more detailed instructions on how you made it on the wiki? I'm trying to build one too so I can use USB Wifi but for a complete beginner, reading schematics is quite challenging.
 
Honestly, the best advice I can give you is to learn how to read circuit diagrams before you go any further.

The circuit diagram is the instructions, so if you learn how to read them, you'll learn how to wire up the USB host filter.
 
GameGod posted on Mar 2 2007 at 03:35 PM said:
Honestly, the best advice I can give you is to learn how to read circuit diagrams before you go any further.

The circuit diagram is the instructions, so if you learn how to read them, you'll learn how to wire up the USB host filter.
Try finding a quick guide with pictures using Google.

There are only 3 symbols to understand on the USB filter circuit. Resistor, Capacitor and Ground. Google those terms and look at the pictures of my USB filter in the FAQ section. Ground is the upside-down tree looking things, connected to any convenient source of ground.
 
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