I did have one of the compass modules (HMC6352) working fine for some time, then suddenly it stopped working, so i bought the second one thinking i had fried the first one somehow, but the CMPS03 compas module doesn't want to work.
Is there a good way to test the I2C interface and prove its working?
Got something else you can connect the areduino to? Another arduino perhaps?
Or maybe use a scope and see if the lines toggle correctly as your interface is working.
the only other thing i have is a gps, servo, led's all stuff that doesn't use i2c, don't have access to an oscilloscope either. Any other ideas really appreciated.
I'm glad this came out just now. I had a problem with Duemilanove and I2C devices, just couldn't figure out what was making me nuts.
I tried this I2CScanner: Arduino as I2C bus scanner – todbot blog , and my Duemilanove couln't find any I2C devices.
As this topic wakes me up again, I take another look to my system, and there it was, too obvious. I was connected my SDA and SCL pins to Duemilanoves digital IO 4 and 5, not Analog IN 4 and 5, as it was in the picture.