is there a standard set of pins that the MEGA 1280 uses for I2C connections. Apparently the library defines specific pins for I2C on some boards (or maybe all boards, not sure). But I cant find out what pins to use.

Any help would be appreciated..



Yes, they are the pins called SCL & SDA. Let me see if I can pull up the Mega1280 drawing …

And there they are - SDA & SCL, also used as D10/D21 apparently.

I2C: 20 (SDA) and 21 (SCL). Support I2C (TWI) communication using the Wire library (documentation on the Wiring website). Note that these pins are not in the same location as the I2C pins on the Duemilanove or Diecimila.

thanks guys working on it now

YOu know it occurs to me that old time programmers have a hard time with some of these boards because they are fixed in their thinking and do not plan for an expandable processor capability.

This is a good example of that scenario. The authors of the libraries set them up so that they would accomodate MANY processors/boards.. even new processors/boards not yet developed and thought of. Whereas us old timers would have defined the pins in our individual programs and when we changed from say an UNO to a MEGA we would have just changed the pins in our program.

The authors of the libraries made all of that unnecessary. Now all I have to do is be smart enough to remember that .... well that and figure out where things are documentated here on the arduino site.

Finding things on this site is not always easy for us old timers that do this stuff part time.

So to all those authors, developers and hackers that make this site work....



Yes, the boards.txt file or something like that takes care of the pin to name kind of mapping.