Lpc2000

--- In lpc2000@yahoogroups.com, Sten <list@n...> wrote:
>
> Does anybody has some experiences in what data rate can be
> achieved when writing to an SD/MMC card? What is the bottleneck
> (software/FAT or SPI)?

Ideally the limitation will be on use of the SPI interface.  Don't 
forget that it's 1/4 the speed of talking natively to the MMC card.  
The file system layer won't add a bottleneck, assuming that you're 
doing block reads/writes to a contiguous area on the media.  I mean 
once the driver knows where to read/write to, there's very little 
additional overhead.

Not to incite a flame war, but is a FAT file system driver really 
that complicated?  I remember back in the day hacking around with 
partition tables and allocation tables and copying sectors with a 
hex editor to fix disk problems, IIRC the filesystem isn't all that 
complicated, is it?  I know FAT32 and VFAT complicate matters, but I 
think that just basic FAT isn't that difficult.  I just can't 
believe that there is no useful open source FAT driver out there.  
This file system has been out for 25+ years now, used on 95% of 
computers in existence...  Would it be that hard to fix the other 
driver found here to overcome the 32MB limit?  It likely doesn't 
work reading the hard drive because the partition table is different 
than on a floppy.  Why wouldn't it work "runinng off of the hard 
drive" accessing the floppy, if it works "running off of a floppy"?