Ethernet shield and SD

The ethernet shield has a SD card slot which "is not supported". Is the problem that there is no library yet or is there a hardware problem? I can find schematics for the ethernet shield but nothing regarding low level interface to it. Is there documentation regarding how to talk to the SD slot so that I could develop my own library?

I just received my Ethernet shield and there is no SD card connector! Just a sizeable blank area on the board :(

You don't need to create your own library, you can use an existing. Just find on which pins the SD slot is connected to and modify the pins on a SD library. I don't know if that works, I'm just thinking loud :P Mine also came without an SD card holder :(

I believe that an SD card is 3.3v and not 5volt. Is compatability a problem with direct connection to the Arduino pins?

Why is the Ethernet shield not compatible with the Mega?

I have a SD card library which is working with arduino duemilenove and the etherned shield.

i had to do sme changes in sd_raw_config.h to use it with ATmega328

I found the library here:

Thanks Google language tools:

I have not made the hardware modifications to my ethernet shield and the library worked with my Nokia 6600 MMC card.

Is compatability a problem with direct connection to the Arduino pins?

Yes: you need to use voltage dividers for the Arduino-->SD pins to lower the output signal to 3.3V. The 3.3V input from the SD card is enough to be seen as a "high", though, so that's okay.

If you search through previous forum postings by people who've gotten SD cards working, you'll find more info on this.


Insofar as I see from the board schematic there are no resistors used. Perhaps that is why they say that SD cards aren't supported.

Why is the Ethernet shield not compatible with the Mega?

With modification of the shield it is AFAIK compatible if you want to go that far.


Do you have any idea what changes are required? The increased memory of the Mega would be very helpful for web enabled uses.

The SPI interface on the Mega is on different pins which is why the standard shield doesn't. It is possible to modify the shield and Ethernet library to work on a Mega. Anyone going to the trouble of populating the SD components on the shield can easily get the thing working on a Mega.

Though after having had my share of head scratching with the ethernet shield's hardware problems, I'd have to suggest that it would be both easier and more productive to investigate other options if you really need SD+Ethernet such as using an entirely separate system and simply interfacing the actual Arduino with serial.

Here is a guide on how to make the Ethernet shield work with the MEGA

The from seems to be unavailable.

Does anyone know an alternative download location?

kind regards


seems to be unavailable.

Worked okay for me.

If you can't get it from another try, email me, and I'll send you a copy.