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Topic: Issues with SPI conflicts between it eat LCD and Ethernet shield (Read 1 time) previous topic - next topic


Hello everyone,

I am a beginner in the arduino platform and with software rather than hardware background so please forgive my possible ignorance.  I have created a project that uses the Ethernet shield and the I read studio 2.8 inch LCD shield. I have tried mounting those stacked on an UNO as well as a mega 2560 controller and I am unable to get both of them working at the same time. I have spent countless hours researching this on the forums and google and I understand that I have two issues:

1. There is an SPI conflict between the Ethernet SS SPI pin and the LCD shield SS pin (10 on UNO 53 on mega)
2. There is a bug on the wiznet 5100 chip that pollutes the SPI bus even when not in use

With regards to issue 1 I have read some possible workarounds that discuss disabling SS pins of either side before use. I have tried to apply them without any hardware mods but I am unsure which is the pin the LCD uses (as far as I understand the conflict is on the sd card of the LCD screen trying to also use 10/53 but I am not using ad)

With regards to issue 2 have looked at some suggested patches to Ethernet/util/SPI.h but looking at my 1.02 installation there is no such header file on the file system and I have been unable to find the code mentioned.

Also I am unsure as to which of the above still applies to 1.02.

I am very tempted to throw either the LCD shield or Ethernet shield away if anyone can suggest a combo that works.

Any help is greatly appreciated.

Ps: I run on osx 10.8.2


I am trying to use a sparkfun ethernet enabled arduino and a homemade SD shield... the problem is they both use pins 13-10 :| ( the ethernet and the SD libraries).


Yes it is probably one of the most common issues people face. And there are many published workarounds. The problem is some of them are quite old and probably not applicable to the latest versions of the IDE, the libs, the boards... So trying to figure out what stands today...

For example with regards to the Wiznet 5100 bug with SPI bus pollution, its a known issue for so long, i cant believe the fix is not included in the latest libraries as a very large percentage of ethernet shields use the same chip.

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