DE2 for data storage (SD card)

Definately too fast for SD card.

The DE2 board's FPGA is only wired to DAT0 on the SD card connector. DAT1-DAT3 are unconnected, and thus, only one-bit transfer mode (or SPI) are possible.

A class 6 SD Card is spec'd to transfer at 6 MB/s, but that is only for reading. Writing is much slower. There are a few faster class cards, but not much faster.

I don't think anyone makes a SD Card that can write data that fast (yet). For the 2.0 spec, the SD_Clk max speed is a maximum of 50 Mhz.

3.0 Spec allows the max clock speed to be 100 Mhz (or maybe slightly more), so future SD Cards may be capable, if the write operations don't delay too long to finish.

The Bottom line is:

1) SD Cards are not this fast yet.

and

2) The DE2 board is not suited for fast SD Card transfers because it does not connect DAT1-DAT3 pins of the SD Card to the FPGA.