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Posts: 2,152 | Thanked: 1,490 times | Joined on Jan 2006 @ Czech Republic
#31
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.
There is real reason. Bigger cards and cards running in high speed mode (50MHz) can draw up to 200mA themselves. SD specifications allow this.

From http://www.transcendusa.com/support/...S16GUSDHC6.pdf :
Current Consumption
The current consumption is measured by averaging over 1 second.
‧ Before first command: Maximum 15 mA
‧ During initialization: Maximum 100 mA
‧ Operation in Default Mode: Maximum 100 mA
‧ Operation in High Speed Mode: Maximum 200 mA
‧ Operation with other functions: Maximum 500 mA.
Together with reader electronics it can easily draw 300mA or more. Even if in reality card draws less, card readers must specify the maximum (usb descriptor is static).
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Posts: 2,152 | Thanked: 1,490 times | Joined on Jan 2006 @ Czech Republic
#32
BTW, the World Smallest Transflash TF / MicroSD USB 2.0 Card Reader Keychain I have here claims it needs 100mA and works when attached to N810 in usb host mode.
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Posts: 71 | Thanked: 58 times | Joined on May 2008
#33
Thats really interesting, especially in light of the previous couple of posts. My next question I guess is, if the readers can be made to work by turning off power management is there any reason not to? Also given that I have some experience of editing in command line which file(s) need editing to do it?

Thanks, you guys are as always amazing.
 
Posts: 10 | Thanked: 0 times | Joined on Aug 2009
#34
Hey guys

I got an All-in-One card reader as recommended in this thread (http://www.dealextreme.com/details.dx/sku.7140).

Sure enough it works, sort of.

Succeed:

* Sony MMC Duo
* Sony MMC Duo via a standard converter
* Micro SD via an standard SD converter

Fails:

* SD card direct
* Sandisk MMC Duo

My goal is to back up photos from my camera while travelling so I figure this will be good enough.

I put in my MMC and copy the photos to my internal MicroSD card so I figure job done!

As a test I copy the files back to a MicroSD in the SD converter and then try to open them on Kubuntu and the images are damaged. The files seem to be corrupt and have lost the original dimensions and only render 1/3 of the pic.

I went back to the 810 and tried to open the same file and it detects as being corrupted.

Any ideas? Anyone seen or got past this?

I hope someone can help me as this is a big one for me.

Thanks in advance.
 
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Posts: 900 | Thanked: 273 times | Joined on Aug 2008 @ Fresno CA USA
#35
Originally Posted by andrewm View Post
Hey guys

I got an All-in-One card reader as recommended in this thread (http://www.dealextreme.com/details.dx/sku.7140).

Sure enough it works, sort of.

Succeed:

* Sony MMC Duo
* Sony MMC Duo via a standard converter
* Micro SD via an standard SD converter

Fails:

* SD card direct
* Sandisk MMC Duo

My goal is to back up photos from my camera while travelling so I figure this will be good enough.

I put in my MMC and copy the photos to my internal MicroSD card so I figure job done!

As a test I copy the files back to a MicroSD in the SD converter and then try to open them on Kubuntu and the images are damaged. The files seem to be corrupt and have lost the original dimensions and only render 1/3 of the pic.

I went back to the 810 and tried to open the same file and it detects as being corrupted.

Any ideas? Anyone seen or got past this?

I hope someone can help me as this is a big one for me.

Thanks in advance.
Was your SD card an SDHC over 2GB? If so that reader won't work. SD cards are backward compatible with SDHC readers but SDHC cards won't read in SD readers.
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N810 -- 5.2010.33-1
 
Posts: 10 | Thanked: 0 times | Joined on Aug 2009
#36
I tried using the usb converter that came with the card and that doesnt work either.

May be a lost dream this one

Also I took the SD card I had added to the device out to back up the files on my pc and the card is no longer recognised. I swear the n810 is cursed.
 
Posts: 540 | Thanked: 387 times | Joined on May 2009
#37
Do you have a digital camera that takes that SD cards (use an adapter)? Reformat card with that. After that, GParted (Linux x86) should be able to read it. Format as ext3 and you should be fine after that. Obviously formatting will loose your files. If there is anything on there you want, try using testdisk (Linux x86).
 
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Posts: 900 | Thanked: 273 times | Joined on Aug 2008 @ Fresno CA USA
#38
Originally Posted by linuxeventually View Post
Do you have a digital camera that takes that SD cards (use an adapter)? Reformat card with that. After that, GParted (Linux x86) should be able to read it. Format as ext3 and you should be fine after that. Obviously formatting will loose your files. If there is anything on there you want, try using testdisk (Linux x86).
NOTE: If you format as EXT3 the SD card won't work in cameras, MP3s and Windows computers.
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N810 -- 5.2010.33-1
 
Posts: 540 | Thanked: 387 times | Joined on May 2009
#39
The point of the camera is because it formats cards more low-level than Windows/Linux/etc. because a desktop OS wants to mount the partitions first. Yes you could use fdisk or whatever, but the camera is guaranteed to work and takes like 5 seconds to format.

I think it's reasonable to assume the card the OP is using is "dedicated" for the NIT. Yes obviously backups would be nice.

And http://www.fs-driver.org/ for Windows.
 
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Posts: 698 | Thanked: 129 times | Joined on Oct 2007 @ CA
#40
hey guys,

i picked up the following reader from fry's, and is fast and has successfully been tested with a 16gb sdhc card and a 4gb memory stick duo card.

http://www.frys.com/product/5265727?...H:MAIN_RSLT_PG

H.
 
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