[En-Nut-Discussion] FAT filesystem and SD/MMC cards

[Arnfinn Aas Eielsen]

Hello

Thanks for the quick reply!

If you think I can use this port you are doing as a filesystem, that 
would be excellent! I'm using avr-gcc, but that won't be much of a 
problem, or?

Also, anyone have an idea about what is needed to "fill in the blanks" 
in the fat file system code?

A.

På 24. jun. 2005 kl. 00.17 skrev Brett Abbott:

> Hi
>
> Im just porting a mixture of Dusan's and xfash to ICCAVR.  Quite a bit 
> to change it to work on Ethernut 2 but getting close.  Will let you 
> know more in a week or so.
>
> Cheers
> Brett
>
> Harald Kipp wrote:
>
>> Hello Arnfinn,
>>
>> Bad news. There is a simple FS for serial dataflash chips
>> http://www.ethernut.de/en/projects.html
>> contributed by Dusan Ferbas. It doesn't take care of wear out and
>> the code is a bit old. No idea if it will still work with the
>> latest Nut/OS.
>>
>> PNUT is optimized (better say simplified) for RAM. It may be
>> too difficult to make it work on Flash Cards.
>>
>> As far as I understood, MMC/SD Cards contain a patented algorithm
>> to avoid flash wear out, even if the FAT is written to the same
>> block over and over again. Anyone with more insight?
>>
>> In general I'd prefer a journaling FS, because it would be useful
>> for all kind of flash memory, not just patented FAT. My interest
>> in the area is enormous, but the required effort...well.
>>
>> The ecos JFFS2 doesn't look bad. Unfortunately it's GPL'ed and
>> won't fit to Ethernut's BSD licence.
>>
>> Harald
>>
>> At 16:40 23.06.2005 +0200, you wrote:
>>
>>> Hello!
>>>
>>> I'm trying to find out how I can read and write files to a SD/MMC 
>>> card using a newly acquired Ethernut 2.1b.
>>>
>>> I have made a mount for a SD/MMC card reader, a voltage divider for 
>>> the output from the microcontroller, and connected it to the SPI 
>>> bus. I have downloaded the "nutmmc" example from 
>>> http://usbdip.de/en/nutmmc/ and it seems to run without problems on 
>>> the hardware.
>>>
>>> Now, I noticed that it is not possible to write files with the FAT 
>>> code that I have found, and I wonder if there has been some 
>>> development here lately. Is there somebody I can ask for some help 
>>> if I have to write the functions myself? You can have whatever code 
>>> I manage to come up with, if it would be of any interest. :)
>>>
>>> Is there perhaps an alternative to the FAT file system when it comes 
>>> to reading and writing the memory card? I noticed something called 
>>> PNUT; is it usable for this kind of application? I don't need to 
>>> read or write to the card from any other device than the Ethernut 
>>> card, so I just need (wish for) an easy and simple way to handle 
>>> files really...
>>>
>>> Any help is appreciated!
>>>
>>> Cheers,
>>> Arnfinn Aas Eielsen
>>
>>
>>
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>>
>>
>
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> Email: Brett.Abbott at digital-telemetry.com
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