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-   General (https://talk.maemo.org/forumdisplay.php?f=7)
-   -   N800 USB Host Mode Experiment (https://talk.maemo.org/showthread.php?t=4177)

paratox 2007-12-07 12:23
Re: N800 USB Host Mode Experiment
 
Quote:
Originally Posted by convulted (Post 102183)
can anybody confirm this adapter works without switching?

skinny 2007-12-07 14:21
Re: N800 USB Host Mode Experiment
 
Quote:
Originally Posted by Tirithen (Post 101366)
I got my wireless USB keyboard working but it dropped a lot of characters until I added 5v from 4AA batteries...
I'm having the same problem.

I'm running OS2008 Beta and I've enabled host mode using the "echo host > /sys/devices/platform/musb_..." method (because I'm using a female-female adaptor, rather than a USB-OTG cable).

The keyboard is detected and "works", but drops a LOT of characters, making it unusable (worse than the repeating characters when using a BT keyboard... which was the problem I was trying to solve by going USB).

Is the only solution to supply power? Do other USB keyboards (mine is a KeySonic Nano) work correctly without power?

luca 2007-12-07 16:38
Re: N800 USB Host Mode Experiment
 
Quote:
Originally Posted by paratox (Post 105566)
can anybody confirm this adapter works without switching?
you need a mini b male to a female, not a mini a to a.

djs_tx 2007-12-07 17:24
Re: N800 USB Host Mode Experiment
 
Quote:
Originally Posted by Master of Gizmo (Post 105173)
Hi,

this host mode support is really great. I just successfully used my i2c-tiny-usb (http://www.harbaum.org/till/i2c_tiny_usb/) to my n800. And with the libusb already pre-installed it was a matter of seconds to get the demo app running on the n800 and having it access the i2c-interface chips and do some LED blinking.

BUT: I have sporadic resets. Not only with my USB hardware but also with e.g. a prolific usb/rs232 converter. I don't even have to run my own drivers or so. A simple "lsusb" will at a 1/3 chance make the n800 reboot.

Has anyone experienced this as well?
Extremely cool... I will be attempting to follow in your footsteps soon.

I would try repeating the lsusb with a powered hub in place and seeing if your problem is related to current draw.

David

dblank 2007-12-07 18:45
Re: N800 USB Host Mode Experiment
 
Quote:
Originally Posted by luca (Post 105564)
I doubt the n800 has enugh horsepower to decode an mpeg stream at full resolution (though I'm used to satellite edit: and I know I have to transcode that, feeding the stream directly to the n800 doesn't work, maybe dvb-t with lower bitrate could work).
And usually these sticks draws a lot more power than the ~100mA that the n800 can supposedly deliver.
Shouldn't the DVB-T device do most of the hard work (decoding) ?

I've run hardware decoders before on really crappy hardware, they didn't tax the CPU at all, maybe these devices are different, though. *shrug*

They probably do use more power than the N800 can supply, but it's actually possible to deliver up to 200mA.

Master of Gizmo 2007-12-07 21:28
Re: N800 USB Host Mode Experiment
 
Quote:
Originally Posted by djs_tx (Post 105670)
Extremely cool... I will be attempting to follow in your footsteps soon.

I would try repeating the lsusb with a powered hub in place and seeing if your problem is related to current draw.

David
You are right, i should give a hub a try. But a) is my device really low power and draws really only a few milliamps b) should drawing even a few milliamps more not reset the n800 and c) is a self powered hub somehow spoiling the fun :)

I have added a small section about my N800 experiments to my i2c-tiny-usb page at http://www.harbaum.org/till/i2c_tiny_usb . Just scroll down to the "Using the device with a Nokia N800" section.

P.S.: Where's the N810?? Can't wait to try this with the N810 ...
BTW: Did they add a micro AB receptable to the N810? Or do we face the same it-only-accepts-a-USB-B-plug problem again?

luca 2007-12-07 21:54
Re: N800 USB Host Mode Experiment
 
Quote:
Originally Posted by dblank (Post 105710)
Shouldn't the DVB-T device do most of the hard work (decoding) ?
No, at most it will do the demuxing (taking out one mpeg stream from the whole mux, and some usb2.0 sticks won't do even that), mpeg decoding (the real hard part) has to be done in software.

LurkerN 2007-12-07 22:19
Re: N800 USB Host Mode Experiment
 
Quote:
Originally Posted by Master of Gizmo (Post 105793)
P.S.: Where's the N810?? Can't wait to try this with the N810 ...
BTW: Did they add a micro AB receptable to the N810? Or do we face the same it-only-accepts-a-USB-B-plug problem again?
The N810 does contain a MicroAB port, but I have not been able to find a Micro-A to full-size B-plug or A-receptacle. Since Nokia does not officially support USB host in the tablets, we must wait for another device to support OTG Micro host so we can borrow those adapters. Until then we must use the same kludges used for the N800.

dblank 2007-12-07 23:03
Re: N800 USB Host Mode Experiment
 
Quote:
Originally Posted by luca (Post 105811)
No, at most it will do the demuxing (taking out one mpeg stream from the whole mux, and some usb2.0 sticks won't do even that), mpeg decoding (the real hard part) has to be done in software.
Wow, that sucks :)

Is there *any* USB2 DVB-T card that also does hardware decoding?

Maybe some day we could actually use that currently useless IVA processor in the tablets for things like this :)

convulted 2007-12-07 23:16
Re: N800 USB Host Mode Experiment
 
Quote:
Originally Posted by luca (Post 105643)
you need a mini b male to a female, not a mini a to a.
Oh yeah, I wonder how I missed that :)


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