Hi,
This may sound stupid, but I am looking for an I2C Ethernet board that I could use with the Arduino since the existing Ethernet Arduino shields are using pins that are already in use on my project.
Any idea if that does exist or if we can modify an existing Arduino Ethernet shield to use other pins?
What kind of others method could I use to send data to a computer regularly without a physical connection to the computer with I2C or pins 1,2 only?
Thank you
You can try this one:
using softwareSerial you can use other pins
if we can modify an existing Arduino Ethernet shield to use other pins?
The SPI interface is part of the CPU, and you're stuck with the pin assignments Atmel made.
I don't know whether there's an Ethernet chip with an I2C interface, but, if there is, it would almost certainly take a large effort to replicate the existing driver libraries on a new chip.
You're probably better off either switching to a Mega to get more pins, or using the I2C interface to add "port expander" chips to free the digital pins needed by the Ethernet shield.
... after looking more on the subject, I found this one:
http://www.adafruit.com/index.php?main_page=product_info&cPath=17_21&products_id=83 which is a XPort shield from adafruit. It seems that with a XPort, it just need 3 pins and not the 9,10,11,12 like usual... which could be fine in my case. Can someone confirm that to me?
Thanks
I know very little about the XPort module: I've never looked at it too closely, because it has an async serial interface, limited capabilities compared to the Wiznet, and a higher price.
It might work for you, but look carefully at the amount of data you'll be transferring, especially on the transmit side, because Arduino's serial output is not interrupt-driven.
There's a Wiznet chip called the W3100a that supports I2C communication. There are also breakout modules available, I have an IIM7010A with it.
What I'm not sure of, is if the higher-level protocol used to create sockets etc. is the same as with the W5100. If it is, is it possible (trivial?) to change the Ethernet library code to use I2C instead of SPI for communication?