Usb Peripherals Using Usb Otg


gHeTTo cHiLd

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Nov 15, 2005
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When I heard about the gp2x and saw the usb port I thought here it is finally an affordable mini-pc like the soekris boards but then with a screen and tv-out, super! Problem is most of my plans vanished once I realised it's only usb slave. (Hold on I'm still not giving up and rooting there is a solution to this).

All they had to do is provide usb-master and this would’ve been ideal. Many applications : run hylafax on it with a usb->rs232 cable and external fax modem (receive faxes and mail them). Hook up a webcam and use it as alarm. Attach usb-wifi and use it for posting ip or waking up other pc’s at home via wake-on lan when necessary.
Finally : use it for robotics projects with http://linuxk8055.free.fr/ etc. So many neat projects I could have invented, all vanish now because there is no usb host port :( . People often answer to this -> use a laptop. But no, this device uses less power, makes no noise (no fans) and is much better suited for robotics projects. Combined with the multimedia and tv-out capabalities this would have been a sweat deal .Problem with other handhelds such as Amida pda for me seems the fear of a too small community behind it …

Ok so what about USB on the go devices like these :
http://www.cooldrives.com/usb-on-the-go-en...re-usb-otg.html

This drive has 'host'+'slave' capabilities on its own. Since it is able to request directory information to the 'slave' device and retreive files afterwards from 'slave'. There is a 2 way communication possible. So in sence in would be possible to use this drive with the gp2x. The big question is will attaching this drive + a usb-hub allow us to use other slave usb-devices? This last one might be a bit mutch but at least the hd usb-OTG solution should be able to work in the future after some hacking.

The other possibility is using the usb-1.1 capabilities of the chip (why o why didn't they include a connection for that or even put a place on the printboard to solder our own connector to it???). Anyone have clues to hard it will be to solder a usb-female to the correct pins to use this usb 1.1 host?

What are other peoples thoughts on this?
 
If you want to do robotics stuff, your probably best off with rs232 as it's still the simplest to use.

Now, the ext connector contains at least 1 uart, and this can be converted to standard rs232 very easily (use a max232 or similar). No need for usb->rs232 converter :)

I'd say the OTG drive you mention can only support one usb device and no hubs, as it's designed for simply copying/backing up of data from your camera or pendrive to itself. To access it as a normal drive, it'll probably require plugging into a usb host port. No one will know unless you try however...
 
If you want to do robotics stuff, your probably best off with rs232 as it's still the simplest to use.

Now, the ext connector contains at least 1 uart, and this can be converted to standard rs232 very easily (use a max232 or similar). No need for usb->rs232 converter :)


Yes but the usb board seemed much easier (it already has linux drivers and supports 8 in/outputs + 2 analogue in/out). Then again now I'm reading GPH is just ignoring the GPL and without a kernel we need to redo all their work before having kernel sources to be able to add new devices. Sorry to say it but I'm feeling glad not having pre-ordered one. Will sit it out and wait what comes out of the bag for this console.

I'd say the OTG drive you mention can only support one usb device and no hubs, as it's designed for simply copying/backing up of data from your camera or pendrive to itself. To access it as a normal drive, it'll probably require plugging into a usb host port. No one will know unless you try however...

Yes the otg drive mentioned is intended only for backing up. But reading the usb specifications I derived that only 1 'host' is needed to give 'slaves' the ability to talk with eachother. . . :
http://www.usb.org/developers/onthego/
Going out and buying 300 euro worth of hardware only to 'test' if it might work is not my kind of thing ;). That's why I posted this. I want people who already have ordered a GP2X to test stuff like this out or give them some ideas on what 'could' be possible.

If something nice comes of it I just might order one myself otherwise I think a psp with 1.5 firmware seems to be a better investment... If the hw hacks don't work out you can still sell it to psp games-freaks :).

Also it is pretty mindboggling to me that the only real advantage GPH offers with their GP2X is using linux and working together with the open source community. Then they shoot itself in the foot by not releasing the kernel sources ???. I mean come on, what are they afraid off? We find some badly written/commented code? Just a sdk (cd or download) is not a big deal. They do the same for most cell-phones : provide a java-sdk download or cd (like for my ericsson T630).
 
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Hi, since I know so so much about electronics here is what I would do:

For usb hosting your going to need a galaxzan transducer, a fibrainian neutronizer, and a sootronian quartz module.

Okay, first take your sootronian quartz module and with a rough surface utensil smooth it down until its megableams in shine. This helps with the transportation wave inducers, trust me.

Then next, plug in the galaxzan transducer into the 2K morph side(not the 2K2 morph side silly) of the now smoothed sootronian quartz module. You should now see enveloping waves of midichlorians fibulating here. This will help with the positronic connection immensely during heuristic manipulation.

Finally add the now peturonized sootronian quartz/transducer component onto the fibrainian neutronizer and wallah. Instant usb hosting for the gp2x.

I don't mean to brag but...your very welcome. ;)

Yep, I don't have a clue what these techy threads are about. I mostly skim them since I'm just now learning the "on" button on my computer makes the pretty picture appear.
I really honestly envy you guys who know electronics and programming like you do. :(
 
The good thing is that for the rs232 you are asking for, you don't need drivers, and so can use it straight away. If you use the usb->rs232 convertor, it will need drivers, and even if it comes with Linux drivers, there's no guarantee they'll work on gp2x linux (I'm guessing the drivers will be x86, not arm), so will probably need a recompile (and no doub't the sources to the drivers are not available).
 
For WiFi, SDIO may be your answer, depending on whether someone does a driver for it.

And besides, didn't you know that the GP2X is secretly a transforming battle monkey robot with plasma missiles, fire breath and flying ninja action?
 
Good news being there is an easy way to use the ext as a rs232 port.
So how about the 1.1 usb supposingly available on the chip but not exposed. Is it matter of just finding the correct pins and soldering a wire or does it require more circuitry?
Allthough, even if we do connect the usb 1.1 we also need the kernel sources from GPH to actually be able to use it or write a driver for it . Or wait until the community ports and patches their own 2.4.x or even better 2.6.x kernels for gp2x which seems just as much work as people working on DSLinux (linux for the nintendo console) have to do.

As far as wifi using SDIO I'm not so confident about it. SDIO devices seem the same like many software devices such as soft-modems (or win-modems) and pcmcia wifi cards: little hardware and a lot of the logic put into the drivers. What this transfers to in practice is we get a few company's selling SDIO wifi cards and supplying closed drivers for windows xp,ce and the like (sometimes a x86 linux binary if we're lucky). But they don't give away the drivers sources and rewriting them will be a daunting task (probably a too great of a task to ask of the gp2x community alone).
 
On the soldering a usb port to the chip, that might not work it is a BGA being we have no reachable pins to solder to. But if they still have PCB traces for it you might to able to cut (or grove into the copper of) the PCB and solder the wires there.. Other then that you (as far as I know) would not need any extra components. But most USB controllers are pin compatible, so if you de-solder the USB2 slave chip and solder on in it's place a USB OTG controller, it might work.
 
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