The functions of the I/O and other pins on each PCB are described Layout that determines the physical design of most shields and other add-onĬomponents. Baseline, in this context, refers to the “classic” Arduino PCB In between there are the DuemilanoveĪnd Uno variants. Identical internally, and consist of a DC voltage regulation circuit and two ICs.įigure 4-1 shows a block diagram of the Diecimila and Duemilanove modelsįigure 4-4 shows the physical layouts for six different baseline Arduinoīoards, from the Diecimila to the Leonardo. Those boards that do not have a USB interface must be programmed using an externalĪrduino types that use the FTDI FT232RL serial-to-USB interface chip are essentially The operation of these parts is transparent when using the Arduino IDE to create In the Uno, Uno R3, and Mega2560 theĪdditional small ATmega processors are preprogrammed to serve as a USB interface. Standard serial (such as RS-232) and USB. The older Arduino models with USB used an FTDI interface chip (the FT232RL), anĪTmega8 (Uno), or an ATmega16U2 (Mega2560 and Uno R3). This part has a built-in USB interface, whichĮliminates the need for the additional chip seen on earlier Arduino models with a Starting with the Leonardo board (2012), the ATmega32U4 XMEGA microcontroller has been Arduino hardware features Board nameĬ Pulse-width modulation outputs (alternate DIO pin functions). Position on a 0.1 inch (2.54 mm) socket header, or the pins extending from theīottom of a shield PCB. “pin” as a connection point of some sort, be it a lead on an IC package, a Shields that plug into these sockets are the actual pins. The connection points on an Arduino board are sockets, and the jumpers and Terminology encountered elsewhere, but it’s not completely technically correct. This is mainly to maintain consistency with the The term “pin” is used in this and other sections when referring to the

Arduino uno pinout definition