Lpc2000

Robert,

If you use MMC or SD cards, the on-board processor (an ARC is many
cases, SanDisk is a fan) wear-levels the flash and swaps out defective
sectors so the host can just regard it as a disk and write wherever it
damn well wants.

If, however, you need a NAND or NOR flash filing system, you need more
complex software...

--
Paul Curtis, Rowley Associates Ltd  http://www.rowley.co.uk
CrossWorks for MSP430, ARM, AVR and now MAXQ processors

> -----Original Message-----
> From: Robert Wood [mailto:robert.wood@apostrophe.co.uk] 
> Sent: 10 November 2005 11:12
> To: lpc2000@yahoogroups.com
> Subject: Re: [lpc2000] Re: Cheap SD Flash File System
> 
> I am no expert on this, but I am lead to believe writing file 
> systems for flash based storage systems is a tricky business 
> if you want to get maximum life out of your flash. 
> Apparently, you need to try and ensure that you write and 
> erase sectors evenly, not just write to whatever space might be free.
> 
> As far as I understand, the physics of how flash works means 
> that if you don't watch how you write to the memory, over a 
> period of time - not only can you wear out the cells you are 
> writing to, but adjacent ones as well.
> 
> This company:
> 
> http://www.hcc-embedded.com/site.php
> 
> do a very neat, very small footprint flash file system for 
> various embedded processors - including ARM IIRC. More than 
> $150, but if what they say is true (and I  suspect it is) you 
> will hugely increase the life of your flash cards.
> 
> Cheers,
> 
> Rob
> 
> 
> 
> 
> ------------------------ Yahoo! Groups Sponsor 
> --------------------~--> Most low income households are not 
> online. Help bridge the digital divide today!
> http://us.click.yahoo.com/cd_AJB/QnQLAA/TtwFAA/dN_tlB/TM
> --------------------------------------------------------------
> ------~-> 
> 
>  
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
> 
>