SDXC and SdFat

Any interest in using SDXC cards with SdFat?

SDXC cards have a capacity from 64 GB to 2 TB. Currently 64GB and 128GB cards are available.

SDXC cards are normally formatted with an exFAT file system but I was able to format a 64 GB SDXC card as FAT32 and use it with a modified version of SdFat.

I used this card

The card seems to be accepted by Windows 7 with the FAT32 format. Windows 7 will only format the card exFAT or NTFS.

The FAT32 formatted card also seems to work with the preview version of Windows 8.

FAT32 formatted SDXC cards work on Linux and Macs and these systems will format an SDXC card as FAT32.

If there is interest, I will post a beta of SdFat that can read, write, and format SDXC cards FAT32.

The current version of SdFat has several problems with SDXC cards and the SdFormatter sketch will not correctly format SDXC cards as FAT32.

FAT32 limits individual files to a max size of 4 GB. The SDXC standard exFAT format has no file size limit.

exFAT is a proprietary Microsoft file system. I am following efforts to produce a stable open source exFAT implementation.

I think that adding sdxc will make sdfatlib more future proof and right now high capacity flash memory is a bit expensive however it will come down as time goes on so as time goes on there will be more and more interest in sdxc so it is a good decision to add sdxc support for both the people who alot of storage and for the people that are going to own sdxc cars in the future and of course for the people who already own one and wish to use it with their avr.


I would actually be very interested in this :) I'm working on a datalogger which will be sitting in a remote location for up to a year which will generate roughly 50GB of raw data, so it would be nice if there would be a good way to store it with the avr.