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dhouston
- 22nd July 2007, 15:38
I have a need to write small amounts of data to an SD card. The data comes in discontinuous flurries of 4 byte chunks and I have about 7mS between chunks to write the 4 bytes to SD (and hopefully to RS232). A normal incident will have a total of 200-532 bytes but there may be incidents that have thousands of bytes.

The examples I've found so far write 512 bytes at a time, using FRAM or RAM to accumulate a page prior to writing. I'd prefer to write each 4 byte chunk as it occurs.

Is it possible to write smaller amounts than 512 bytes? Does anyone have a URL to an explanation of reading/writing to SD? Better yet, does anyone have an example of writing small amounts of data to SD?
bbarney
- 22nd July 2007, 16:05
Have a look at this
http://www.compsys1.com/workbench/On_top_of_the_Bench/MMC_Project/mmc_project.html
dhouston
- 22nd July 2007, 18:38
Have a look at this
http://www.compsys1.com/workbench/On_top_of_the_Bench/MMC_Project/mmc_project.html
I had already seen that and I interpreted it as requiring 512 byte writes. Am I misinterpreting it?
bbarney
- 22nd July 2007, 19:15
Probably not I didn't really read it just thought you might not have seen the site before.this might help even though it's for proton
GioppY
- 23rd July 2007, 10:09
Yes you can!
Anyway the block must be closed with exactly 512 bytes.
Absolutely necessary the "ProdManualSDCardv1.9.pdf" from Sandisk
Regards
Gianni
dhouston
- 23rd July 2007, 11:55
Absolutely necessary the "ProdManualSDCardv1.9.pdf" from Sandisk
Thank you! That looks like a great resource.
bbarney
- 23rd July 2007, 17:45
Dave here's a link to a newer manual
http://www.digitalspirit.org/file/?aff=,/docs/sd/ProductManualSDCardv2.2final.pdf
leisryan
- 8th November 2007, 01:30
Probably not I didn't really read it just thought you might not have seen the site before.this might help even though it's for proton


Sir that code is cool!!! have you ever tried porting it to PBP? i would like to share it from you ifsoever

Trully,
Ryan
Brock
- 8th November 2007, 02:11
Dave here's a link to a newer manual
http://www.digitalspirit.org/file/?aff=,/docs/sd/ProductManualSDCardv2.2final.pdf

That link doesn't seem to be working. I did a google search and all links for that file are from
that website. They must have moved the file.
bcd
- 9th November 2007, 11:04
Try http://www.digitalspirit.org/file/index.php/obj-download/docs/sd/ProductManualSDCardv2.2final.pdf

Bill.
Ioannis
- 9th November 2007, 11:23
That link is OK. Thanks!

Ioannis