Ethernet shield schematic?

Apparently I was asleep and missed the announcement about the official Arduino Ethernet Shield.

Would it be possible to get a schematic for it? I and a coupe of buddies have the WizNet module, and I have already developed a shield for the module. I’d like to make them match up electrically for maximum code compatibility.


You know I was just thinking about this as well.
As well as the schematics
Does anyone know where you can buy one in the UK?

Apparently I was asleep and missed the announcement about the official Arduino Ethernet Shield.

I’m not entirely sure there was an announcement–I certainly haven’t seen one.


Take a look on Ebay uk
There is a supplier in South London and the schematic can be downloaded from their Ebay site.

Thats the one from nuelectronics based on the ENC28J60 not the official Arduino sheild.
It wont work with the libraries supplied with the Arduino IDE.
But they do supply there own.

Im not sure what the benefits of the different versions are.


Im not sure what the benefits of the different versions are.

The ENC28J60 only provides layer 2 (ethernet) functionality. THe Wiznet based model (the official ethernet shield and the WizNet module) provide layer 3 and 4 functionality. This leaves the ATmega free to do more interesting things. I suspect the XPort used on LadyAda’s shield leans toward the “more functionality” end of he spectrum, but I don’t know for sure.


if you have a 811mj module (which was just superceded like 2 days ago by the 812, dammit!), you can use the schematic/layout for my ethernet shield v1.2

We did finally make the announcement of the ethernet shield (sorry for the delay). Schematics and EAGLE files here:

Was looking at the eagle board design files and I don’t see where the SPI connections are made to the pass through jumpers to the arduino. Am I just overlooking something?

Am I just overlooking something?

They use the ICSP header for MISO/MISO/SCK instead of pins 11/12/13. I’m guessing this is to circumvent possible issues with the pin 13 LED on early generation Arduino NGs, or maybe that’s just because the routing worked out to be easier that way.

The ethernet shield will have the added benefit of adding the 3.3V and RESET pins to the headers, even for the NG and earlier boards that didn’t have them. If that magjack isn’t too tall, shields making use of those pins can have them provided even if the underlying arduino is an NG, or even an old single sided serial (of which I have at least 3).


Well, I thought about that, but physically looking at my board, I can see the traces to pins 11,12,and 13 but i don’t see them on the board design in Eagle. Also, if it were using the icsp header, wouldn’t I have to have a female connector on the bottom of the shield (which I don’t have) to mate up with the ICSP pins on the Arduino. I’m pretty sure this is the same board shown in the pictures (I bought it from NKC a couple of days ago and it was described as “official”.) Sorry for being dense, just trying to learn… :slight_smile:

[Edit: My board is a little different. I see the icsp header on the schematic now - I just don’t have one. Strange…]

Maybe I shouldn’t make so many assumptions looking at just the schematic, not having any hardware in hand. :expressionless:


Hey - no sweat. I was just trying to figure out how to the sd slot was connected and thought it was curious that the 2 official’s didn’t match up. Thanks for the input though.


pins 11,12,13 are the same ones as the ICSP connector that is the hardware SPI port on the processor.

Understood, but what I was saying was that the board design file doesnt match up with the hardware I purchased. Not a big deal - I was just wondering which design was the latest “official” (and which was “better”). :slight_smile:

Whoops. I had accidently uploaded a work-in-progress version of the ethernet shield files. I replaced them with the ones that correspond to the released version of the shield.

Thanks for the updated files - JC

Interesting - I notice on the “work in progress” version there’s a transistor to slave the SPI enable and slave select lines. I assume this was to work around the Wiz’s SPI design flaw (MISO does not go hi-Z when SS is in active, as the SPI spec requires). That chunk of the circuit is gone from the production version. Did Wiz update the device to correct that problem, did the workaround have some problem, or was there some other design decision involved?


looking at my board, I can see the traces to pins 11,12,and 13 but i don’t see them on the board design in Eagle.

OK; I’m confused. I downloaded the eagle files from the official site, and I see traces from pins 11, 12, and 13… And no connection to the ICSP connector. Are we talking about multiple different schematics or something? There ARE at least three different ethernet boards floating around:

  1. Official Arduino board using Wiznet TCP/IP chip.
  2. Adafruit board using application-level modules from Lantronix (and I guess the Wiznet module as well, in the latest version.)
  3. nuelectronic board using Microchip ethernet controller.
    I’d label the Wiznet chip as being layer 4 (TCP/IP), the lantronix modules at layer 7 (telnet, ssh, http), and the microchip part down at level 2 (bare ethernet); the boards cover a wide range of options…

So why the big “not supported” sticker on the SD card? It looks to me like it has all the relevant connections. Is something wrong with it, or is it just lacking SW support?

Mellis replaced the designs earlier today with the current version where the SD card is not connected to the SPI pins.