Arduino Uno + Petit FAT + 8 GB SDHC (RAM issue)

Hi all!

I’m currently developing a program that already uses 57% of my RAM (I have 867 bytes left, which I may need for local variables and some other parts of my project as well).
I’d like to be able to wirte some data to my 8 GB SDHC card (FAT32) but the <SD.h> Arduino’s library requires 512 bytes for buffering (that I don’t have).
I’m looking for alternative ways to deal with this memory issue and I found the Petit FAT library:
http://elm-chan.org/fsw/ff/00index_p.html
According to it’s feature description, it has low RAM comsumtion (44 bytes work area + certain stack).
The problem is that, in orther to use this library, I need to edit a file called “diskio.c” to act as a “low level disk I/O module to control your storage device”. I have no idea on how to configure it…

So, do you know what should I write on this file?
Or, do you know any other alternative to deal with this RAM issue?

Aditional info:

  • I have the SPI ports to use (10,11,12,13).
  • The link to the library I found: library.
  • I only need to write some info to a .txt file or (if necessary) a .bin file, (I don’t need do manage directories/read files/…).

Thanks!
Arthur.