Temporizzazioni MMC

Do you have a question? Post it now! No Registration Necessary

Translate This Thread From English to

Threaded View
Ciao a tutti!
Qualcuno ha un'idea delle temporizzazioni necessarie per le memorie MMC?
Mi spiego meglio, qualcuno conosce il transfer rate per una scrittura
continua su questi dispositivi? (riferendosi a una MMC "media" odierna,
da 512MBytes).

Vorrei realizzare un datalogger, che abbia una banda di 150KBytes/sec in
scrittura sulla MMC, e mi chiedevo se con queste memorie la cosa fosse
fattibile o meno.

Ho visto che esistono scritture
-single block
-multiple block

Il dato che proprio non riesco a trovare da nessuna parte e' la durata
di un trasferimento "single block" (512 bytes).

Grazie a tutti e ciao!

Re: Temporizzazioni MMC
Bongiorno Aldo,

Quoted text here. Click to load it

I don't understand Italian much but I think it would be best to ask the
supplier, for example Lexar, for a detailed data sheet. This speed does
not sound very high, should be possible.

Have you also considered SD cards? Supposedly they are really easy to
communicate with and they are physically very small. Also, at least in
the US you can almost buy them at every street corner.

Ciao, Joerg


Re: Temporizzazioni MMC
I'm so sorry..... my intention was to post this on an italian newsgroup,
but I unintentionally posted it here...I apologize....seems that I
pushed the wrong button on my mailer.

Anyway, thanks for your answer,you exactly got the point :-)

I think it should be possible, too, because digital cameras seem to
write data at a higher speed.

Concerning SD, is the specification publicly available like MMC or CF,
or has to be purchased?


Joerg wrote:
Quoted text here. Click to load it

Re: Temporizzazioni MMC
Hello Aldo,

Quoted text here. Click to load it

That's ok, I guess we are all pretty international in these newsgroups
anyway. I bought a TV in Germany a long time ago. The manual was in
Dutch/Danish/Swedish and the buttons on the front were marked in
Italian. Oh well. Still works fine. When I read "Unita d'alimentazione"
in an Italian schematic I somehow craved a nice Italian dinner...

Quoted text here. Click to load it

Yes, mine writes a 1MB JPEG set in about a second or so but it uses an
older Lexar flash card. Reading it down to the PC is even faster. A
friend has one with an SC card and it also stores a whole picture of
probably 2MB worth of compressed data in less than a second. You can
even record realtime movies with it.

Quoted text here. Click to load it

The manufacturers have that, along with application notes about more
unusual writing schemes such as 1-bit wide writing. I would look at the
mfg web site. You may have to contact them. Also, this topic is often
discussed in great detail in micro controller newsgroups such as the
Yahoo MSP430 group. There you can also get help if things don't want to
work as expected.

For MMC and SD here is an overview to start with:


Then, on to more detail when your design begins:


Another good source is this organization:

http://www.sdcard.org /

Ciao, Joerg


Site Timeline