by David John Barker » Fri May 03, 2013 1:11 pm
That's a very good question! You are quite right, running at 3.3v there would not normally be any need for a level shifter chip. However, all of the Firewing shields are compatible with Arduino, which runs at 5v. You will see this chip a lot in boards designed for Arduino.
In summary, Firewing shields are pin and voltage compatible with Arduino.