Arduino>>MMC interface

I’m looking for a MMC interface resource(samples, code). My goal is to write sensor data to a MMC card using the Arduino IDE. Has there been any work in this direction?

Many Thanks,


It can be done. Generally. See e.g. the functions in avrlib (it’s even allready in a subfolder of the arduino package!)
Or a very nice MMC/SDC C library for AVR micros over here: (sorry, german only)

But if you want to read the card directly on a computer as a standard mass storage device, you have to wirte the data in a certain filesystem description. Something like FAT16, FAT32 etc. I’m pretty shure the Atmega8 has to less flash memory space and RAM for that… I saw working projects with Atmega32’s and up, though. (i.e. on the hardware side, FAT filesystem is possible with the wiring board)

Alternatively, you can write your own simple data format. But this requires a custom software, if you want to read the data back on a computer.
Well, all depends on what you want to do with the card, when the data is written. What kind of data will you collect and why on a MMC card?


well sorry no help.

but i’m interested too by an external memory.
cause i’m sure that 8K it’s a bit short for my program in arduino…

but perhaps there is a simple solution to add memory (16Ko) but not a bunch like an MMC card.
Have you solutions ?

this sort of project (SDCard) was announced in the road map 1 year ago ::slight_smile:
and so… nobody found this idea really interesting to develop ?:o




as usual, this has only been a problem of time. There have been tests with SD cards, but nothing fruitful so far. And the reason is that we don’t have enough time to develop everything we would like to have available due to the huge load with internationalization, workshops, etc.

However if you want to give a hand, we used Ulrich’s code as mentioned earlier in this topic, as a starting point.


I know that there are sd to serial adapters around. even sparcfun has them. would that do something for you?

Sparkfun sells the dosonchip modules. So far, people are complaining about the information available for working with these. It seems that this module is better documented: