Compatibility with 2 gigabyte and larger SD cards has been poor, due to the SD/MMC protocol using a 32-bit address field denominated in bytes. The SDHC standard addresses this limitation by using 32-bit block addresses instead. Both SD and SDHC are traditionally accessed as 512-byte blocks on 512-byte boundaries, so the change to host software or firmware is minor but required. Before SDHC was standardized, various manufacturers "extended" the SD control block fields for their 2GB and 4GB cards in different ways. Those cards are incompatible with many SD and some SDHC devices, as they conform to neither standard. All SDHC readers work with standard SD cards.[10]
Many older devices will not accept the 2GB size even though it is in the revised standard. The following statement is from the SD association specification:
"To make 2GByte card, the Maximum Block Length (READ_BL_LEN=WRITE_BL_LEN) shall be set to 1024 bytes. However, the Block Length, set by CMD16, shall be up to 512 bytes to keep consistency with 512 bytes Maximum Block Length cards (Less than and equal 2GByte cards)."[11]
Since all cards up to and including the 1GB card use a fixed 512 block size, some device drivers do not handle the larger block size and will not even recognize the 2GB card.[citation needed] Citation for this is more difficult as the SD organization hides this problem. SanDisk web site shows examples of devices such as the iPAQ 1910 that will only support 1GB cards and the Epson Photo RX300 Technical support says they only support 1GB cards in the SD slot.[citation needed] Many early card readers only support 1GB, based on user experiences.
the SD 2.0 standard in SDHC uses a different memory addressing method (sector addressing vs byte addressing[13]). SDHC cards only work in SDHC compatible devices, but standard SD cards work in both SD and SDHC devices. The SDHC trademark is licensed to ensure compatibility.[14]
I hate to be the one to say it, but I don't think we will see a rom or anything else that will give SDHC compatibility to the Axim. If all it needed was a driver or rom update, I think we would have seen it already, if it were possible. And given that there are no 2gb cards that are SDHC, and the Axim officially only supports 2gb memory cards, why would they have put SDHC in, in the first place? (Note the officially. I know that you can use cards bigger than 2 gb, but according to dell themselves, after 2gb you are on your own.)
My 4GB SDHC Class 2 card works perfectly well in my Axim 51v. What I'm wondering next is if I can get away with an 8GB SDHC Class 6 card. Of course I could always get an 8GB Class 2 card, but I'd prefer a Class 6.
Tried a Kingston 4GB SDHC class 6 card in my Dell Axim X51v. Didn't work. The PDA didn't recognize the card, and it didn't show up.
However, I also have a Dell E1405 laptop that has a built-in 5-in-1 card reader. Dell's website lists this as supporting only Memory Stick, Memory Stick Pro, Secure Digital, MultiMediaCard, and xD-Picture Card. I asked an online Dell tech support person if the reader will support SDHC. He was less helpful than a sack of 50 lb peanuts, and only quoted the specs as listed in the Dell manual.
I tried the SDHC card in the reader ... no dice. HOWEVER, I also found a non-public Microsoft hotfix that solved the problem! You have to email MS support and ask for access to this file, but after I installed the hotfix the reader worked with the SDHC card!!
My question regarding those SD Hotfixes is if they'll work with non-SDHC readers; I'm betting 'no', and those hotfixes are probably just there to fix issues with SDHC readers like the MicroMate from Sandisk.
SDHC according to Microsoft = SDIO standard Host Controller
SDHC according to SanDisk = SD High Capacity
It's got nothing to do with SDHC functionality.
Thanks! For clearing that up.
I also noticed that registry key but was to afraid to ask what it was. I thought maybe I was just seeing things. :hide: I don't want to end up in an insane asylum.
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HP IPAQ 211: WAD, WA, PocketPlus, PocketWeather, MemMaid, Pocketmusic, etc.
im using an A-data 4GB flash card i got in 9/2006
works fine with my axim. 50v a05 rom
from what i've found you can use 4gb flash cards as long as they arnt SDHC
there arnt too many of them but they can be found though froogle with out much hassle.
Last edited by saberliner; 07-12-07 at 05:53 PM.
Reason: new stuff
Um.. the video didn't say SDHC worked fine - the COMMENTS below did. And we've had quite a few people in the "Compatbility" thread post about how SDHC wasn't recognized.
a russian programmer by the name of a sport has gotten an sdhc hack working, but i don't think we're allowed to talk about it. looking forward to the 8gb SD cards myself, though.
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