Well, SD cards are by their very nature 3.3v, so this is 3.3v compatible.
What you should be asking is "is it 5V compatible?"
I see nothing in the schematics there to drop the signals from the Arduino down from 5v to 3.3v. The other way around won't matter, as the Arduino can read 3.3v signals just fine. With nothing to drop the signals going from the Arduino to the card down to 3.3v you would at worst fry the card. At best, it might work. I don't fancy the longevity of the card though.
You should put something in place on the MOSI and SCK lines to get a 33% reduction in voltage. You can try simple voltage dividers - a 1:2 divider should drop to 3.3v - say 1K? and 2K?.
Yeah, I ment 5v. compatible. (modified the title) Okay, thanks majenko. I coudnt detect a voltage drop either, but I'm not a electronic wizz so maybe I missed it. Ill put the outgoing Arduino signals trough a level shifter.
It wouldt have been nice if they mentioned it in the specs.
I think the pullup to 3.3v are meant to make it work with 5v signal.
I think they will work with 5v input signal.
these sell for like $2 and change, you can buy 2 and experiment with one.
I was looking into these as well and was considering them since they come with 3.3v regulator and I can use that to power an enc28j60 ethernet module (which go for $5 and change). if small size (footprint) is not an issue, w5100 shield with micro sd now goes for $12 so I just went with the w5100 ethernet shield.
I think the pullup to 3.3v are meant to make it work with 5v signal.
The pull-up resistors won't stop 5v from getting dumped into the SD card.
these sell for like $2 and change, you can buy 2 and experiment with one.
It's not the board that you will kill - it's the SD card you plug in to it - no matter how many of these boards you buy for $2 it's the more expensive SD cards that you will have to replace.
Hi,
The intention for this type of card is to use the pullups to 3.3V and have the Library switch from pulldown to off by changing pinMode. Did they provide a library?
Other low-cost SD modules use series resistors.
Problem with all of these is they slow things down and often don't work or work only with SPI slowed down to 1/4 speed.
Ohhh… of course! Now the scematic makes sense. No they did not provide a library. I've already used the module successfully with a level shifter and the SD.h library what comes with the Arduino IDE.