I purchased a Barton I2C LCD and despite its NPX driver chip , the I2C description in the manual was very poor. With the Bus Pirate connected to the I2C LCD it took only a couple of hours of experimentation to test all LCD functionality (and correct all misleading parts of the manual) The BP saved me hours of debugging. Very simple to use to drive serial busses. It is simple enough to upgrade to the latest FW. The Sparkfun version sold by Amazon however is equivalent only to the ver 3a of the original DangerousPrototype versions (but this in not a hindrance for functionality). Note : The Bus Pirate's built-in frequency generator is producing duty cycles well below the demanded one when driven above 1MHz , so be careful relying on the freq generator.