N800 USB OTG Adapters/Dongles - Page 17 - maemo.org

jolouis | # 161 | 2008-02-27, 14:21 | Report

Originally Posted by

Well, I don't see any reason why hi-speed (2.0) vs. full-speed (1.0) should have much correlation with power draw, but I haven't looked.
The difference in speed is bigger than you seem to think; full-speed is 12 Mb/s, while hi-speed is 480 Mb/s. Getting 100 Mb/s through a hi-speed link is plausible, while you're not likely to get more than 8 Mb/s sustained over full-speed. I don't consider that moot, but if hi-speed devices that work directly can't be found, it's no great loss.

The USB 2.0 device requires more power because it's a higher-power chipset in it to handle both the faster USB 2.0 interface and the full 100mbps ethernet link. In the end I haven't been able to get the USB 2.0 device working yet to confirm but I would be strong money that it's a mute argument simply because I doubt the tablet has the horsepower itself to sustain 100mbps transfers (I've got older PCs with PCI NICs that max out their CPU transferring at about 70mbps...); you have to remember that doing a network transfer requires CPU power unlike just doing a direct read/write to the memory card from a host PC. If you're thinking about using the wired networking as high-speed alternative to the wifi you've got the wrong idea... it's more for places where you cannot get wifi but have a wired connection available (hotel rooms, for example).

toby.c13, yes that's correct, the first link is for the USB 2.0 adapter, the second is for the USB 1.1 version which is capable of being powered from the tablet directly. The USB 1.1 version would be what I'd supply so that you did not need an externally powered USB Hub to use it. There is no way to have an adapter simply "split into two", I'd have to integrate a small hub into a dongle-type of cable somehow to make it work; I'm still doing some research on that type of possibility.

The PS/2 adapter is doable, just keep in mind that there's no mouse cursor in Maemo yet so it'd really only be useful for remote desktops/VNC. The crazy thumb keyboard thing is cool but I'll have to see, I've never seen anything like that before... and rs232 should be possible, will require additional software install though.

Thanks,
-Rob

Benson | # 162 | 2008-02-27, 15:19 | Report

Yeah, I realize there'd be a bottle-neck at some point, wasn't really thinking at the time though... Still, I think we could do a lot better than ~8 Mb/s max that can be expected from full-speed. I think you're wrong regarding mem-card write over USB -- I'm pretty sure that goes through the kernel, too. Anyway, with 802.11g going to 54 Mb/s, I wasn't really hoping to beat that (even 100 Mb/s is not worth the inconvenience), it is just for places with only wired connection available indeed, and I'd be glad of even a slow link there.

I think people have been able to make cursors work in OS2008; is it different from 2007? I haven't had the chance to get back to that yet since the upgrade. And I think they have a cursor in KDE, at least I thought I saw it in some screenshots, so it might be handy for the followers of PB.

Edit: Oh, and when you say "possible", you mean commercially possible (you think there's actually someone else who'd buy)? or just technically, and we have to wait and see how many phony accounts I can sign up to say "I'll buy one!"?

Last edited by Benson; 2008-02-27 at 15:23.

roblynn | # 163 | 2008-02-27, 18:34 | Report

Originally Posted by jolouis View Post

I'd have to integrate a small hub into a dongle-type of cable somehow to make it work; I'm still doing some research on that type of possibility.

If it can help, I am an embedded software developer familiar with Cypress' line of USB chips (and with the SL811HS chipset in particular). I have their developer kit (CY3662 - EZ-811HS) to play with. Note that this chip is USB1.1 -- but it is probably cheaper than their 2.0 offering. Regardless, one would need to pair it with an MCU of some sort (an 8bit one would be ok). Just a thought.

Robert B.

jolouis | # 164 | 2008-02-27, 18:48 | Report

Well after doing some tests I don't think the LAN speed is a factor at all; you're correct in that the CPU does get utilized when doing USB transfers, but the controller seems to operate in a different way than when doing network transfers as the speeds that I get when testing over the network are not the same as a direct USB connection. In the end using MaemoFTP I got sustained transfer rate of 700 KB/s (approx 5Mbps) across either Wireless or USB wired network; the CPU at this point maxes out and cannot push any more data across. I haven't tried with the browser, but I imagine if you do a similiar test you'll probably end up with the same sort of results (probably a little higher but around the same sort of range) in that the tablet will go quite quickly, but that's quickly in terms of Internet speeds, not actual LAN speeds.

I know there's been a lot of work on mouse support (there was talk of an app that would poll for a mouse and enable it if found/etc), I just haven't kept up with that thread. None the less, just don't expect it to work "out of the box" under Maemo, that's all! Note I say Maemo, not "N800"... if you're running KDE, you're not running Maemo...

And when I say possible for the serial adapters, I mean I can get one or two of them for a reasonable price from the same supplier as my other equipment, so it's commerically viable even if there isn't a lot of demand. Some of the other things are not in the same boat, so I need to make sure there is a demand before I purchase them in quantity.

One more thing... I may have a lead on a VERY COOL USB cable/device, I'll give you more info when I hear back from my suppliers about availability.

Thanks,
-Rob

GeneralAntilles | # 165 | 2008-02-27, 18:53 | Report

Originally Posted by jolouis View Post

I know there's been a lot of work on mouse support (there was talk of an app that would poll for a mouse and enable it if found/etc), I just haven't kept up with that thread. None the less, just don't expect it to work "out of the box" under Maemo, that's all! Note I say Maemo, not "N800"... if you're running KDE, you're not running Maemo...

Well, if you want to get technical, nobody is running maemo on their tablets.

maemo is the development environment—ITOS is the operating system on the tablets. Still, when you run KDE, you're just not running Hildon/Matchbox, most of ITOS is still there.

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tlacuache | # 166 | 2008-02-27, 22:22 | Report

Just got the OTG adapter/dongle I ordered in the mail. Works great. Thanks!

toby.c13 | # 167 | 2008-02-28, 04:18 | Report

Originally Posted by jolouis View Post

The USB 2.0 device requires more power because it's a higher-power chipset in it to handle both the faster USB 2.0 interface and the full 100mbps ethernet link. In the end I haven't been able to get the USB 2.0 device working yet to confirm but I would be strong money that it's a mute argument simply because I doubt the tablet has the horsepower itself to sustain 100mbps transfers (I've got older PCs with PCI NICs that max out their CPU transferring at about 70mbps...); you have to remember that doing a network transfer requires CPU power unlike just doing a direct read/write to the memory card from a host PC. If you're thinking about using the wired networking as high-speed alternative to the wifi you've got the wrong idea... it's more for places where you cannot get wifi but have a wired connection available (hotel rooms, for example).

toby.c13, yes that's correct, the first link is for the USB 2.0 adapter, the second is for the USB 1.1 version which is capable of being powered from the tablet directly. The USB 1.1 version would be what I'd supply so that you did not need an externally powered USB Hub to use it. There is no way to have an adapter simply "split into two", I'd have to integrate a small hub into a dongle-type of cable somehow to make it work; I'm still doing some research on that type of possibility.

The PS/2 adapter is doable, just keep in mind that there's no mouse cursor in Maemo yet so it'd really only be useful for remote desktops/VNC. The crazy thumb keyboard thing is cool but I'll have to see, I've never seen anything like that before... and rs232 should be possible, will require additional software install though.

Thanks,
-Rob

hmm.. im interested in getting the linksys usb 1.1 too..

ohh.. so can the tablet support multiple usb usage?
say i use a external usb hub.. for the LAN network, keyboard n thumbdrive, will it work?

I saw the ps/2 adapter being sell on some malaysian forum.

---

edited: which usb keyboard should i go for?

i. Tabletkiosk USB Folding Keyboard
http://www.tabletkiosk.com/tkstore/p...ory=24#details

or

ii. Targus Universal USB Portable/Foldable Keyboard
http://www.targus.com/us/product_det...?sku=PA875U01X

Last edited by toby.c13; 2008-02-28 at 18:08. Reason: added stuffs

qole | # 168 | 2008-02-28, 20:07 | Report

I received my OTG adapter yesterday! Works great!

What's the consensus on hooking up a USB Ethernet adapter? Is it purely for when you can't get wireless, or is there some speed advantage?

briand | # 169 | 2008-02-28, 20:17 | Report

I also received my OTG adapters yesterday, and they look great and work well. Thanks jolouis!!

PS: qole -- your desk is far too orderly and neat!

qole | # 170 | 2008-02-28, 20:46 | Report

Originally Posted by briand View Post

PS: qole -- your desk is far too orderly and neat!

No. I just cropped out the piles of crap in Gimp