Arduino DUE + SPI Pins Ethernet Shield

Official Hardware Mega Due
1

Hi to everybody,

I managed to use a DAC MCP4922 with my Arduino DUE and now I would like to use also an ethernet shield.

At the moment to use the DAC I´m taking the SPI pins directly from the Arduino Board as in the following picture:

When I will plug in the Ethernet Shield those pins will be occluded.

I would like to know to what pins on the ethernet shield they will correspond.

Thanks in advance for your replies,
Fabrizio.

2

So, my question is:

where can I find the pins:
SCK
MOSI

When I connect the Ethernet shield to the Arduino DUE?

For the CS pin there is no problem because I can also use the pin 52 (the 10 is for the Ethernet shield and the 4 is for the SD Card)

Thanks in advance,
Fab.

3

As far as I know this is the only header where you can pick up the SPI pins but i could be wrong. They may be rerouted in software but I do not know this for sure (check STM user manual) . I have developed a protoshield for the DUE to try and break these pins out but even this can be problematic because of the height discrepancies between the male and female headers.
http://togglebit.net/2013/06/11/quick-note-on-the-spi-header-of-the-protoshield/

4

Hello f.schiano,
dan@togglebit.net is right. SAM3X8E has only one SPI controller (SPI0) with 4 chip selects (CS0-CS3). Only SAM3X8H has 2 SPI controllers (SPI0/SPI1).

What I would recommend is to make the Ethernet shield and your DAC to share the SPI pins. In order to to that you will need to unsold and replace the SPI connector with a one that permits access to the SPI pins. Just a thought. Regards!

5

This is a gripe of mine with my Ethernet shield. It has to be on the top if you use other shields that connect with the SPI signals.

That said, it is hard to find the 2x3 connectors with long tails, the only ones I found were in proto shield kits. Does anyone know of a source in the U.S. ?

6

noblepepper:
That said, it is hard to find the 2x3 connectors with long tails, the only ones I found were in proto shield kits. Does anyone know of a source in the U.S. ?

Try: SamTec: SSW-103-03-F-D
From: http://www.samtec.com

I've used them once to build a pass-thru board with an Ethernet shield on top.

-Chris

7

May this can help you:
http://forum.arduino.cc/index.php?topic=168914.msg1256758#msg1256758
it requires some soldering but it is not so complicated.

8

@noblepepper you can find them on eBay

9

I will use an Arduino protoshield I think and I will take out the ICSP pins :slight_smile: