I would like to interface the RCM5600W with the Arduino Duemilanove (http://arduino.cc/en/Main/ArduinoBoardDuemilanove) using i2c. The problem is the serial port of the RCM5600W operates at 3.3v but the Arduino operates at 5v. Any suggestions on how to connect them?
Not sure about the Rabbit 5000 series, but the ports should be 5V compatible. So you can just connect them directly to each other. The Arduino should see the 3.3V signal levels.
If this is for a commercial product (not just a once off build) you’ll have to level translate between the two chips.
For level translation, you may want to use something like the MC14504B
There are other ways of getting it done, but this is perhaps the simplest…
[Edit: Check that, the I2C bus is open drain with pullups, isn’t it? This chip isn’t going to work in that environment…]
[Edit: Here’s a I2C-specific level translator:
Sorry for the confusion.]