EFFS Standard

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embedded_guy
Posts: 5
Joined: Sat Jul 16, 2011 11:15 am

EFFS Standard

Post by embedded_guy »

I am looking to use the EFFS-Standard for an external serial flash device. One thing I noticed is that in fs_main, memory is malloc'd for the file system. What is this memory used for by the file system?

Any help is appreciated.

Thanks.
ecasey
Posts: 164
Joined: Sat Mar 26, 2011 9:34 pm

Re: EFFS Standard

Post by ecasey »

Hi,

At page 16, the EFFS-STD-R1P84 PDF Document in the ../nburn/examples/EFFS folder says:
Memory Allocation
There are some larger buffers required by the file system to handle FATs in RAM and also to buffer write processes.
There is a call to each driver to get the specific size of memory required for that drive. It is then up to the user to allocate this memory from their system.
These buffers vary in size depending on the precise chips being used and their configuration. For further information see description of fs_mountdrive function and the fs_getmem_xxx functions in the relevant driver sections.
EFFS-STD is meant for interfacing directly with flash chips. If you are going to use SD or MMC cards, use the EFFS examples (as opposed to the EFFS-STD example) The EFFS examples do not allocate any memory for use by the file system.

Ed
embedded_guy
Posts: 5
Joined: Sat Jul 16, 2011 11:15 am

Re: EFFS Standard

Post by embedded_guy »

Thanks for the reply.

I am trying to use the EFFS-STD in a non-standard way in that I am interfacing it to a serial flash instead of a typical flash device. I think the STD library is a better fit for this case. I'm trying to determine if there are write issues with the descriptor writes.

Does anyone understand how EFFS-STD writes the descriptor to the flash? The files seem to be written on the boundaries given during initialization, but the descriptor seems to be written at any boundary needed by the library. This causes problems with the serial flash.

Also, this seems to change with the descriptor cache setting. I'm not sure how yet though.

Any help is appreciated.

Thanks.
embedded_guy
Posts: 5
Joined: Sat Jul 16, 2011 11:15 am

Re: EFFS Standard

Post by embedded_guy »

I am trying to use the EFFS-STD in a non-standard way in that I am interfacing it to a serial flash instead of a typical flash device. I think the STD library is a better fit for this case. I'm trying to determine if there are write issues with the descriptor writes.

Does anyone understand how EFFS-STD writes the descriptor to the flash? The files seem to be written on the boundaries given during initialization, but the descriptor seems to be written at any boundary needed by the library. This causes problems with the serial flash.

Also, this seems to change with the descriptor cache setting. I'm not sure how yet though.

Any help is appreciated.

Thanks.
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