Skip to content

Arduino Yun- A New Arduino Microcontroller Board

The Arduino Yun is a newcomer microcontroller board in the Arduino boards family. It is a microcontroller board based on the ATmega32u4 (datasheet) and the Atheros AR9331. The Atheros processor supports a Linux distribution based on OpenWRT named Linino. The board has built-in Ethernet and WiFi support, a USB-A port, micro-SD card slot, 20 digital input/output pins (of which 7 can be used as PWM outputs and 12 as analog inputs), a 16 MHz crystal oscillator, a micro USB connection, an ICSP header, and 3 reset buttons.
The Yun distinguishes itself from other Arduino boards in that it can communicate with the Linux distribution onboard, offering a powerful networked computer with the ease of Arduino. In addition to Linux commands like cURL, you can write your own shell and python scripts for robust interactions.
The Yun is similar to the Leonardo in that the ATmega32u4 has built-in USB communication, eliminating the need for a secondary processor. This allows the Yun to appear to a connected computer as a mouse and keyboard, in addition to a virtual (CDC) serial / COM port.
The Bridge library facilitates communication between the two processors, giving Arduino sketches the ability to run shell scripts, communicate with network interfaces, and receive information from the AR9331 processor. The USB host, network interfaces and SD card are not connected to the 32U4, but the AR9331, and the Bridge library also enables the Arduino to interface with those peripherals.


Because the Yun has two processors, the specification section shows the characteristics of each one in two separate tables.
AVR Arduino microcontroller
  • MicrocontrollerATmega32u4
  • Operating Voltage5V
  • Input Voltage5V
  • Digital I/O Pins20
  • PWM Channels7
  • Analog Input Channels12
  • DC Current per I/O Pin40 mA
  • DC Current for 3.3V Pin50 mA
  • Flash Memory32 KB (of which 4 KB used by bootloader)
  • SRAM2.5 KB
  • Clock Speed16 MHz
Linux microprocessor
  • ProcessorAtheros AR9331
  • ArchitectureMIPS @400MHz
  • Operating Voltage3.3V
  • EthernetIEEE 802.3 10/100Mbit/s
  • WiFiIEEE 802.11b/g/n
  • USB Type-A2.0 Host/Device
  • Card ReaderMicro-SD only
  • RAM64 MB DDR2
  • Flash Memory16 MB
  • PoE compatible 802.3af card support (see the note below)



  • Arduino Yun x1

The Arduino Yun- A New Arduino Microcontroller Board appears in the following collections: