[psas-software] Re: [PSAS Avionics] More flight computer thoughts

Hugo Vincent hugo.vincent at gmail.com
Wed Oct 12 14:16:37 PDT 2005


On 12/10/2005, at 10:43 PM, Andrew Greenberg wrote:
>> OTOH, some of the MTD documentation states that SmartMedia cards are
>> just NAND flash, and may be accessible.

> SmartMedia uses a SPI interface. Blech. Possible, but at only 5 Mbps, that's way slow.

No, SmartMedia and xD cards are raw NAND flash (i.e. the same signals as bare NAND chips). Its reasonably fast (for us it was *very* fast because we had a FPGA-based controller).

MMC (and to an extent, SD) use a (fast) SPI connection.

We have used xD on a few projects at my work (http://www.bluewatersys.com), where we needed very specific control over things like wear leveling (which you can't get access to with MMD, Compact Flash etc.), with good success.

Hugo Vincent.

P.S. I have been lurking on these lists for a while and this is my first post.
Congratulations on your recent launch! 

Check out the project I have been working on:
http://johnstowers.no-ip.com/wiki/index.php/Main_Page
(served from a home computer, so its slow, and often down - if so, try again later)





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