Arduino Yún Mini is a breadboard PCB developed with ATmega 32u4 MCU and QCA MIPS 24K SoC CPU operating up to 400 MHz. Qualcomm Atheros CPU supports a Linux distribution based on OpenWRT named Linino. The board has built- in WiFi ( IEEE 802.11b/g/n operations up to 150Mbps 1x1 2.4 GHz ) supports 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 connector, an ICSP header, two reset buttons and one user button. The Arduino Yún Mini is similar to the Leonardo in that the ATmega32u4 has built-in USB communication, eliminating the need for a secondary processor. This allows the Arduino Yún Mini to appear to a connected computer as a mouse and keyboard, in addition to a virtual (CDC) serial / COM port.
The Arduino Yún Mini is open-source hardware! You can build your own board using the following files:
It is recommended to power the board via the micro-USB connection with 5VDC. If you are powering the board though the Vin pin, you must supply a regulated 5VDC. There is no on-board voltage regulator for higher voltages, which will damage the board. The power pins are as follows:
The ATmega32u4 has 32 KB (with 4 KB used for the boot loader). It also has 2.5 KB of SRAM and 1 KB of EEPROM (which can be read and written with the EEPROM library). The memory on the AR9331 is not embedded inside the processor. The RAM and the storage memory are externally connected. The Yún Mini has 64 MB of DDR2 RAM and 16 MB of flash memory. The flash memory is preloaded in factory with a Linux distribution based on OpenWrt called Linino OS. You can change the content of the factory image, such as when you install a program or when you change a configuration file. You can return to the factory configuration by pressing the "WLAN RST" button for 30 seconds.
The Linino OS installation occupies around 6 MB of the 16 MB available of the internal flash memory. You can use dogUSB with a micro SD card or dog eMMC a 4GB Flash if you need more disk space for installing applications.
Atheros AR9331 pins: Each of these pins can be used by LininoOS side as peripherals of Linux Kernel. In addition, some pins have specialized functions:
AVR 32u4 pins: Each of the 20 digital i/o pins on the Yún Mini can be used as an input or output, using the pinMode(), digitalWrite(), and digitalRead() functions. They operate at 5 volts. Each pin can provide or receive a maximum of 40 mA and has an internal pull-up resistor (disconnected by default) of 20-50 kOhms. In addition, some pins have specialized functions:
There are 3 reset buttons with different functions on the board:
The Yún Mini has a number of facilities for communicating with a computer, another Arduino, or other microcontrollers. The ATmega32U4 provides a dedicated UART TTL (5V) serial communication. The 32U4 also allows for serial (CDC) communication over USB and appears as a virtual com port to software on the computer. The chip also acts as a full speed USB 2.0 device, using standard USB COM drivers. The Arduino software includes a serial monitor which allows simple textual data to be sent to and from the Arduino board. The RX and TX LEDs on the board will flash when data is being transmitted via the USB connection to the computer. Digital pins 0 and 1 are used for serial communication between the 32U4 and the AR9331. You can use Ciao library to communication between the processors.
Arduino Ciao is an easy-to-use and powerful technology that enables Arduino sketches to communicate intuitively with the "outside World". It aims to simplify interaction between microcontroller and Linino OS, allowing a variety of connections with most common protocols, third-party services and social networks.
Ciao has been designed and developed to be modular and easily configurable. Its goal is to support several connectors capable of interacting with the system resources (filesystem, console, memory) and to communicate with the most common and useful protocols (XMPP, HTTP, WebSocket, COAP, etc..) and applications (Jabber, WeChat, Twitter, Facebook, etc.).
Ciao Library is a lightweight library that can be used inside sketches for MCU to send and receive data, via serial communication, in a simple and intuitive way. A SoftwareSerial library allows for serial communication on any of the Yún mini's digital pins. Pins 0 and 1 should be avoided as they are used by the Bridge library. The ATmega32U4 also supports I2C (TWI) and SPI communication. The Arduino software includes a Wire library to simplify use of the I2C bus;. For SPI communication, use the SPI library. The Yún Mini appears as a generic keyboard and mouse, and can be programmed to control these input devices using the Keyboard and Mouse classes. The onboard Ethernet and WiFi interfaces are exposed directly to the AR9331 processor. To send and receive data through them, use the Bridge library. The Yún Mini also has USB host capabilities through Linino OS. You can connect peripherals like USB flash devices for additional storage, keyboards, or webcams. You may need to download and install additional software for these devices to work.
The Arduino Yún Mini can be programmed with the Arduino software (download) or the Linino IO (www.linino.org). Using Arduino IDE Select "Arduino Yún mini from the Tools > Board menu (according to the microcontroller on your board). The ATmega32U4 on the Arduino Yún Mini comes preburned with a bootloader that allows you to upload new code to it without the use of an external hardware programmer. It communicates using the STK500 protocol. You can also bypass the bootloader and program the microcontroller through the SPI signals that are available on the pin headers.
Rather than requiring a physical press of the reset button before an upload, the Yún Mini is designed in a way that allows it to be reset by software running on a connected computer. The reset is triggered when the Yún Mini's virtual (CDC) serial / COM port is opened at 1200 baud and then closed. When this happens, the processor will reset, breaking the USB connection to the computer (meaning that the virtual serial / COM port will disappear). After the processor resets, the bootloader starts, remaining active for about 8 seconds. The bootloader can also be initiated by pressing the reset button on the Yún Mini. Note that when the board first powers up, it will jump straight to the user sketch, if present, rather than initiating the bootloader. Because of the way the Yún Mini handles reset it's best to let the Arduino software try to initiate the reset before uploading, especially if you are in the habit of pressing the reset button before uploading on other boards. If the software can't reset the board you can always start the bootloader by pressing the reset button on the board.
The maximum length and width of the Yún Mini PCB are 71.12 mm and 22.86 mm respectively. Weight of the board is 16 g.
The Arduino Yun Mini can be complemented by three accessories: the dogRJ45, the dogUSB and the dog eMMC. The first is an Ethernet port that can be added to the Arduino YUN Mini if one needs this type of port for their specific project. The second one, dogUSB, is a USB port featuring also a slot for a mini SD to extend the memory of the board. The last one, which is dogUSB eMMC, is really the latest novelty in terms of accessories: it’s a USB port with an integrated 4 Giga of Flash. The user can add either a single accessory or two, according to their needs.
|dogRJ45||IEEE 802.3 fast ethernet switch|
|10/100 Mbps fast ethernet port|
|dogUSB||USB A type connector with USB 2.0 hub|
|Micro SD connector with card reader|
|dog eMMC||4 GB Flash|
|USB port type A|
|Architecture||MIPS 24K processor operating at up to 400 MHZ|
|Operating Voltage||3.3 V typ.380 mA (113~570 mA)|
|Flash Memory||16 MB|
|RAM||64 MB DDR2|
|Clock Speed||400 MHz|
|WiFi||802.11 b/g/n 2.4 GHz|
|Ethernet||802.3 10/100 Mbit/s|
|Flash memory||32 KB|
|Clock Speed||16 MHz|
|Analog I/O Pins||12|
|DC Current per I/O Pins||40 mA on I/O Pins; 50 mA on 3.3 V Pin|
|Input Voltage||5 V|
|Digital I/O Pins||20|
|Power Consumption||170 mA|
|PCB Size||23 x 71.1 mm|