The R3 uses an ATmega 16U2 while the older revisions uses the 8U2. So, we need an FTDI programmer for the purpose of uploading the code/sketch into the chip. FTDI programmer When you first plug in ...

The 16u2 is normally used as the Arduino Uno’s USB interface. The only external hardware needed is a single 120 ohm resistor. The original Apples had cassette and speaker interfaces.

[jelengar] liked the ease of use of the Arduino, but wanted a much higher pin count. He set about converting the ATmega Controller for use with Wiring, the code that the Arduino IDE is based on. Th… ...