Lpc2000

Rob Jansen wrote:
> Bill W. wrote:
> 
> 
>>It may make sense to align cluster size w/flash erase block size.
> 
> 
> Indeed.
> The 21xx flash memory has got some weird sector seizes.
> The 213x series has 8 x 4kB, 14 x 32 kB and then 5 x 4kB (in that order) 
> and for the 212x it is even worse: 8 x 8kB, 2 x 64 kB and 7 x 8kB.
> The 210x and 211x series use a sector size of 8kB for all their sectors.
> 
> You can (as far as I know - never did this myself) perform partial 
> programming of a sector. The IAP functions as described in the 213x user 
> manual will allow you to write to Flash in 256/512/1024/4096 byte blocks 
> but you have to erase sectors on full sector sizes. This will definitely 
> not match your FAT file system.
> 
> Samuel wrote:
> 
> 
>>I need to basically do relative addressing when logging or
>>calling the log file, any help will be appreciated
> 
> 
> I'm not sure what you mean by "relative addressing"?
> If it is just logging data you need to do the easiest way is to just use 
> reserve some sectors for logging and start using these without any 
> difficult file system. You could either create a directory which tells 
> you date/time/filename and the start position of the file in memory or 
> define a structure that defines what the block is about and what its 
> length is.
> 
> Depending on the application and the amount of data I would opt for an 
> MMC/SD card for logging. Log the data on your application and then just 
> plug the SD card into a PC and a PC application will show your data.
> I am going to use this for logging data and updating software (on boot 
> check for presence of SD card, check for new software and reprogram 
> flash if needed)
> 
> See also http://groups.yahoo.com/group/lpc2000/message/9293
> 
> Regards,
> 
>     Rob
> 

Correct! If you want to log data continously only, why you want to spent
a lot of time in implementing a file system? Just write your data
byte4byte to your flash and wrap around if it is full.
If there are other reasons for using a file system, a flash file system
like JFFS(2) could be better solution than FAT. Because it is balancing
write/erase cycles to your flash other than FAT. Just have look to the
Linux kernel (the greatest resource of open-source code in this world!).
Check the uClinux resources and mailing list for a good (bug-free)
implementation, too.

Regards,
  Sten


-- 
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