uALFAT 16GB SD support

I’m having a problem with uALFAT firmware rev 3.13 and a 16GB micro-SD memory card. My circuit works perfectly every time with a 2GB SD card. When I try a 16GB card I get a non-zero ACK most of the time when I issue the ‘I’ command to mount the card. In these cases the ACK is usually 0x05 (SD timed-out) but is sometimes 0x07 (Failed to send command to SD card). Every now and then it successfully mounts the card.

It seems to me that it takes longer to mount a large SD card, and the uALFAT internal timeout is not long enough in most cases. I believe I have the latest firmware loaded. Is there any way to fix this problem?



I suggest to e-mail GHI directly. This forum is mostly about .net micro framework line of GHI products. So, community wise you probably won’t get much help.

Other than that, welcome to the forum!

Can confirm that it takes longer to mount larger SD cards. Had the exact same problem (with timeout period) when developing SD card library for AVR. 2GB SD card mounted slower than 512MB card.

The impression I got from the GHI web page was that all technical questions should be directed towards this forum. I’ll try to find an appropriate email address.


Please see note under USB/Storage Modules