I’m currently working on a SD card library for NETMF. The speed I’m currently reaching is so fast that I’d like to share this info to the community. (I actually had to slow the clock down to make sure SDRAM could follow :p)
Current speed on FAT32 formatted SD-card is around 3.44MByte / s (see screenshot).
I still have some work on the library as it now seems that I need to reset the board if I want to start a new debug session…
Another GEM from RLP master! Awesome! ;D
For those of us that don’t regularly use SD… What is the current speed record?
Find read/write speeds of the current NETMF implementation here: http://tinyclr.com/forum/1/1858/
The write function is next on my list, I will post a write speed benchmark too.
@ Wouter
Will this be an open source driver?
Impressive work.
Would be nice to have something like this in RLPLite for OSHW boards.
Wow… So, if I read this correctly. The previous speed record was 559 KB/s and you have it up to 3.44 MB/s. Impressive is an understatement. Good job!
Architect: I will not open-source the library. In fact it is an RLP port of the open-source FatFs (FAT file system module) by Chan, who did some amazing work: FatFs - Generic FAT Filesystem Module
@ ianlee: you’re comparing with USB speed, SD speed is 320KB/s 
Thanks for the link. I see some ports for STM32 there. Good start.
Ah! I thought those were all just different brands of cards. Well, now you’re just bragging! And you’ve earned the right to do so!
@ Wouter Huysentruit
Impressive!
Will you be sharing this in any way?
Selling as a lib, GNU…
Awesome work…
I am looking forward to your write speed performance testing.
Just did a write test on a lazy SD card (will test on microSD later) and these are the results:
written 4194304bytes in 6160ms. So that makes a write speed of 664,9kByte/sec. Which I think is the upper limit of the card in use.
Oh and this speed is with FAT file system.
results with microSD with FAT filesystem:
written 4194304 bytes in 2246ms, so 1.78MByte/second. Fair enough 
Did a read-back of the written data on the same microSD card and the read speed is 4.44MByte/second.
It almost needs a heat-sink
@ mytech: I might sell the library, but I’m currently struggling with the debugger.
When visual studio resets the board before deploying, I hear the USB unplug sound, but the board doesn’t come back. I need to hit the reset button manually before deploy continues…
Seems like it has something to do with the RLP InstallInterrupt function, but can’t figure it out. Maybe it’s a bug in the RLP framework?
I like these numbers!
Impressive work indeed…
The issue with VS is a common one, this happens to me a lot especially if i have multiple VS windows open… so it is a bug somewhere but can’t pinpoint it either… and i do not use RLP…
SD card video test: