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dfinch is offline dfinch
2009-02-11 , 03:29
Posts: 362 | Thanked: 82 times | Joined on Jan 2008
#21
Originally Posted by DCN810 View Post
Have people had reasonable experience (returns or credit if needed) with brando.com.hk, considering it is HongKong, and that I would be risking $18 on thier CardReader in a car
(USB Racing Car All In One + SIM Card Reader) at:
http://usb.brando.com.hk/prod_detail.php?prod_id=00246
I am actually looking for something that reads SIM and miniSD. Thanks
Be careful. I know nothing of the company but do ensure that the reader will work with an N810. Most of the ones tried don't. See above for some that do work.
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DCN810 is offline DCN810
2009-02-11 , 06:32
Posts: 5 | Thanked: 0 times | Joined on Feb 2009 @ Washington, DC
#22
Originally Posted by dfinch View Post
Be careful. ..... reader will work with an N810. Most .... don't. See above ......
1. Thanks Derek, Nelson, & Others - You usefully & clearly communicated the many card readers don't work (unpowered especially) with N810. And listed some that do work. I will go with the $8+ Targus for direct connect N810.
2. Thanks Fragos, thaibill for your experience with Brando.com. I should have made clear that I realized that I would probably have to hook
the Brando "USB-All-in-1-+SIM-CardReader-in-a-Racing-Car" to a big box with power.
- madison
 
RichS is offline RichS
2009-02-26 , 17:40
Posts: 71 | Thanked: 58 times | Joined on May 2008
#23
This unsupported reader situation seems very strange to me. Having read about the power issues with any usb device I've tried two micro SD only readers. Neither of which work (just for reference the SanDisk micromate and a Kingston version). Is there any way of verifying that it is a power requirement that they are not meeting? It seems unlikely that they are drawing more than 100mA.
 
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fragos is offline fragos
2009-02-26 , 20:12
Posts: 900 | Thanked: 273 times | Joined on Aug 2008 @ Fresno CA USA
#24
Originally Posted by RichS View Post
This unsupported reader situation seems very strange to me. Having read about the power issues with any usb device I've tried two micro SD only readers. Neither of which work (just for reference the SanDisk micromate and a Kingston version). Is there any way of verifying that it is a power requirement that they are not meeting? It seems unlikely that they are drawing more than 100mA.
My Canon S3 IS's SD card couldn't be read either and it is externaly powered. Digital cameras are for all practical purposes are card readers over USB.
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RichS is offline RichS
2009-02-26 , 20:38
Posts: 71 | Thanked: 58 times | Joined on May 2008
#25
Having done some further research both card readers I have tried are programmed to request 500mA from the usb. I suspect this is just laziness on the part of the programmer as most usbs will provide this so why bother actually finding out what is needed. All we can hope for is either a firmware update or generic firmware for card readers which only requests 100mA. It doesnt seem likely but maybe its a job for the linux community at large.
 
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fragos is offline fragos
2009-02-26 , 20:52
Posts: 900 | Thanked: 273 times | Joined on Aug 2008 @ Fresno CA USA
#26
Originally Posted by RichS View Post
Having done some further research both card readers I have tried are programmed to request 500mA from the usb. I suspect this is just laziness on the part of the programmer as most usbs will provide this so why bother actually finding out what is needed. All we can hope for is either a firmware update or generic firmware for card readers which only requests 100mA. It doesnt seem likely but maybe its a job for the linux community at large.
Does this 100mA vs 500mA issue imply that a powered hub would get these non-functioning card readers to work on the tablet?
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RichS is offline RichS
2009-02-26 , 20:56
Posts: 71 | Thanked: 58 times | Joined on May 2008
#27
It should do from what I have read. However this entirely defeats the point of my plan which is to have such a small usb expansion that it doesnt get in the way of normal use.
 
johnpad is offline johnpad
2009-02-28 , 12:27
Posts: 78 | Thanked: 57 times | Joined on Jul 2007
#28
Same problem for my recent purchase: http://www.kingston.com/flash/usb_microsd_reader.asp

On a more positive note, using my Nokia 6220C as a MicroSD reader over USB works perfectly as far as I have tested it. Appears on usb as sda and gparted (Easy Debian) seemed happy with it. Now I am trying to understand why pb won't let me choose usb as a backup destination which is the main reason for setting this up ...
-John
 
johnpad is offline johnpad
2009-03-27 , 11:54
Posts: 78 | Thanked: 57 times | Joined on Jul 2007
#29
FYI

Just tested the same Kingston MicroSD reader (http://www.kingston.com/flash/usb_microsd_reader.asp) using the bConfigurationValue hack and it seems to work fine.

What is the risk of damaging the hardware if a USB device requests more power than can be provided?

-John
 
sjgadsby is offline sjgadsby
2009-03-27 , 12:26
Posts: 5,335 | Thanked: 8,187 times | Joined on Mar 2007 @ Pennsylvania, USA
#30
Originally Posted by johnpad View Post
What is the risk of damaging the hardware if a USB device requests more power than can be provided?
I think there's little danger to the tablet. It simply won't provide more than its limit. As for the card in the card reader, if a write fails, I suppose you might wind up with a corrupted file or file system on the card.
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