I did a fruitless search here trying to find a microSD size spec for the ethernet shield+Uno. So what size SD card is its max? 32g? 64g? More?
The max size is 32GB.
This is the limit for all types of SD cards on Arduino. Arduino only supports SD (2GB and less), and SDHC (more than 2GB and up to 32 GB).
Cards larger than 32GB are SDXC and are not supported by arduino libraries.
SDXC cards are pre-formatted with Microsoft's proprietary and patented exFAT file system. Microsoft does not publish the specifications of exFAT and its use requires a non-free license. Therefore I have not attempted to support SDXC cards in SdFat. SdFat is the base library for the Arduino SD.h library.
fat16lib:
The max size is 32GB.This is the limit for all types of SD cards on Arduino. Arduino only supports SD (2GB and less), and SDHC (more than 2GB and up to 32 GB).
Cards larger than 32GB are SDXC and are not supported by arduino libraries.
SDXC cards are pre-formatted with Microsoft's proprietary and patented exFAT file system. Microsoft does not publish the specifications of exFAT and its use requires a non-free license. Therefore I have not attempted to support SDXC cards in SdFat. SdFat is the base library for the Arduino SD.h library.
Ty for the details. I wasn't sure as to how large it would accept. I have only seen tutorials with photos of fairly small cards (2-4g). I just didn't want to end up buying something incompatible and useless to me.
+1 on SDXC, use them on my Nikon D7000 (2x 64g) though full size, not microSD. I am surprised to hear about the Microsoft proprietary format. Shocked that Nikon (Japanese corp) caved and paid M$.
Upon googling, I found this...(not relevant to these forums but pertains to the SDXC). Apparently they can be re-formatted easily so could be supported if reformatted to Fat32.
http://www.go4retro.com/tag/sdxc/
Yes they could be reformatted and I have an SDXC that I am playing with on Arduino.
The problem is that Microsoft can prevent reformatted SDXC cards from being used in their OSes and probably in Macs and many other devices that must license their exFat format.
The SD association states that reformatted cards shall not be accepted by SD association members in products they produce.
I am looking at the Linux exFat driver but it is so incomplete. Much of the exFat file system is still a mystery and the code has many gaps in file system declarations.
I expect there will be a good reverse engineered description of exFat and good open source code soon.
Wolfiesden:
I am surprised to hear about the Microsoft proprietary format.
I'm not.
Bill, have you ever had any success with formatting SDXC cards with FAT32? Best regards, Dani
Bill, have you ever had any success with formatting SDXC cards with FAT32? Best regards, Dani
The SdFat SdFormatter example will format a SDXC card FAT32. The card will work on Windows. It should also work on OS X and Linux.
Windows does not allow formatting volumes larger than 32 GB as FAT32 but accepts larger volumes.
Great, thanks!