usage of the reseverd byte in oob area

[Raj Kumar Yadav]

-----Original Message-----

The oob offset 0x4 in small page (512 byte pagesize) flash is marked as
reserved.
Is this byte reserved for any specifc present or defined future h/w or
s/w use? 
Or left for the software to interpret and use it suitabily? 
 
I have a requirement of 7 bytes for the ECC code (currently it is 6
bytes).
Can I use the reserved byte as extra bytes for the ECC code of 7 bytes?
 
As the remaining 8 bytes of OOB area are used by the JFFS2 and YAFFS1. 
 
--------------------------------------------------------

Hi All,

OK, my question (seems too silly and totally out of context) 
could not find merit for a reply. the additional data on this:

As per the document "mtdnand.ps", for small page flash 
(with 512 byte pagesize and 16 byte oob), the oob area is 
used for 
 1) ECC bytes 
 2) two reserved bytes (one byte for badblock, other byte ???)
 3) filesystem specific info (JFFS2/YAFFS1).

The document "mtdnand.ps" also says, if anyone want to use 
the Hardware ECC, he have to store the badblock information
into some known area of flash (NAND_BBT_*).

After this the badblock byte and other reserved byte in the 
oob area is available for Hardware ECC. 

Now, I would like to know, can one use the other reserved 
byte for hardware ECC, while still using the badblock marker 
byte for its intended role. With additional reserved bytes, 
Total 7 bytes are available for hardware ECC (BCH). The 
hardware can take scattered positions for ECC bytes.

The question is more about 'should' than 'can'.

Please point me, if this is not the right mailing list for 
this query.


Thanks,
Raj Kumar Yadav