electr0daves mmcsd and fat

smee · Joined: 16 Jan 2014 Posts: 24

Hello, i have been using electr0daves drivers for a couple of years now, and they work quite well.
But i am finding it difficult to source SD cards.
I have a Toshiba 512mb mini SD, that the mmc and fat drivers worked with, and i have been using that image with ghost, and restoring it to 1gb and 2gb SD cards, (ghost sorts out enlarging it ).

Some of the cards are quite problematic, so i wrote the sdhc driver, that i posted in the library, as i was hoping to use sdhc cards of 4gb or 8gb.
It didn't work.

I have a couple of questions really,

Does anyone know why mmcsd/fat driver doesn't work with the factory formatted cards as they come out of the box ? (I have to put my Toshiba image on them, and formatting under Windows doesn't work either).

And why the driver doesn't work with the 4gb sdhc cards ?

Thanks.

Ttelmah · Joined: 11 Mar 2010 Posts: 19215

The reason for the format problems is ExFAT. This is another Microsoft format, and is the default for a lot of larger cards. Windows will default to using this, but can be told to use FAT32, which will then work with the standard drivers.
As with the extended filenames on FAT32, MS has patents on lots of parts of this, so drivers can't be generated for these extra bits without potentially getting into trouble.
The other question is whether the drivers you are using support MBR.
SD's can be formatted like floppy disks (no partition table), or like hard drives (with a partition table). By default all the Windows formatters will generate a partition table, while formatters on things like cameras will sometimes use the floppy layout. The driver you use needs support for the partition table if it is going to work with Windows formatted drives.

empty · Joined: 13 Jan 2018 Posts: 14

As an addition to what Ttelmah said, be careful when you format your SDHC card and don't use ExFAT because it will not work for you!
SDHC card with size = 4 or 8GB can be formatted with FAT32 also, but unfortunately CCS C original drivers (without any modifications) do not support that size, don't waste your time!
Try with these drivers which are the original ones but with some modifications, they may work for you:

https://simple-circuit.com/ccs-c-fat-library-for-mmc-sd-cards/