Pololu
Arduino Uno R3
Note: This product is manufactured in Italy by affiliates of Arduino Srl, and the product packaging suggests downloading the Arduino IDE from arduino.org. H...
Note: This product is manufactured in Italy by affiliates of Arduino Srl, and the product packaging suggests downloading the Arduino IDE from arduino.org. However, we use and recommend using the normal Arduino IDE from arduino.cc, which is the IDE we ensure our Arduino libraries work with.
Arduino Uno R3, top view.
Overview
The Arduino Uno is a microcontroller board based on the ATmega328. It has 20 digital input/output pins (of which 6 can be used as PWM outputs and 6 can be used as analog inputs), a 16 MHz resonator, a USB connection, a power jack, an in-circuit system programming (ICSP) header, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer (or appropriate wall power adapter) with a USB cable or power it with a AC-to-DC adapter or battery to get started.
The Uno differs from all preceding boards in that it does not use the FTDI USB-to-serial driver chip. Instead, it features an ATmega16U2 programmed as a USB-to-serial converter. This auxiliary microcontroller has its own USB bootloader, which allows advanced users to reprogram it.
The Arduino has a large support community and an extensive set of support libraries and hardware add-on “shields” (e.g. you can easily make your Arduino wireless with our Wixel shield), making it a great introductory platform for embedded electronics. Note that we also offer a SparkFun Inventor’s Kit, which includes an Arduino Uno along with an assortment of components (e.g. breadboard, sensors, jumper wires, and LEDs) that make it possible to create a number of fun introductory projects.
This is the 3rd revision of the Uno (R3), which has a number of changes:
- The USB controller chip changed from ATmega8U2 (8K flash) to ATmega16U2 (16K flash). This does not increase the flash or RAM available to sketches.
- Three new pins were added, all of which are duplicates of previous pins. The I2C pins (A4, A5) have been also been brought out on the side of the board near AREF. There is a IOREF pin next to the reset pin, which is a duplicate of the 5V pin.
- The reset button is now next to the USB connector, making it more accessible when a shield is used.
Warning: We recommend not connecting the Arduino to USB while it is powered through VIN. See this forum post for more information.
Choosing the right controller
The table below compares the Arduino Uno, Leonardo, and our A-Star 32U4 Prime controllers. The A-Star Primes are based on the same ATmega32U4 AVR microcontroller as the Leonardo and ship with Arduino-compatible bootloaders. The Primes also offer many advantages, including superior power management that enables efficient operation from 2.7 V to 11.8 V (LV version) or 5 V to 36 V (SV version).
Arduino Uno R3
Arduino Leonardo
A-Star 32U4 Prime LV
A-Star 32U4 Prime SV Microcontroller: ATmega328P ATmega32U4 ATmega32U4 Clock: 16 MHz resonator 16 MHz crystal 16 MHz crystal User I/O lines: 20 23 26 PWM outputs: 6 7 7 Analog inputs: 6 12 12 Ground access points: 4 4 43 User LEDs: 3 3 3 User pushbuttons: — — 3 Reset button:
Power switch:
Buzzer option:
microSD option:
LCD option:
Arduino-compatiblebootloader:
USB connector:
B
Micro-B
Micro-B
USB/regulatorpower selection: partial partial TPS2113A High-performance
reverse-voltage
protection:
Recommendedinput voltage: 7 V to 12 V 7 V to 12 V 2.7 V to 11.8 V 5 V to 36 V Regulator type (5 V): linear linear switching
step-up/step-down switching
step-down Available
5 V
output
current: at 3 V in — — 0.75 A — at 5 V in — — 1.5 A 0.2 A at 7 V in 1.0 A 1.0 A 1.5 A 1.0 A at 9 V in 0.5 A 0.5 A 1.5 A 1.0 A at 11 V in 0.35 A 0.35 A 1.5 A 1.0 A at 24 V in — — — 1.0 A via USB
connector 0.5 A(1) 0.5 A(1) 1.5 A(1) 1.5 A(1) Weight: 28 g 20 g 13 g to 33 g
1 With sufficiently capable USB power supply.
Side-by-side comparison of the A-Star 32U4 Prime LV microSD to the Arduino Leonardo.
Jargon buster
Plain-language definitions for the technical terms used above.
- ATmega328P
- An 8-bit microcontroller chip used on many Arduino Uno-compatible boards. Knowing the controller uses an ATmega328P helps you understand its memory, speed, pin compatibility, and the Arduino sketches it can run.
- AVR
- AVR is a family of 8-bit microcontrollers used in many classic Arduino-style boards. If a USB host library mentions AVR support, it suggests the examples or compatibility may be aimed at those older microcontroller boards.
- Bootloader
- Small starter software on a microcontroller that lets new code be uploaded before the main program runs. Knowing how to enter bootloader mode matters when you need to program the board or recover it after a faulty sketch.
- I2C
- I2C is a two-wire communication bus used by many sensors and small modules. It matters because several I2C devices can share the same two wires, but each device needs a compatible address and your controller must support I2C.
- IDE
- Short for Integrated Development Environment, a program used to write, run and manage code. It matters because some learners prefer a traditional coding workspace instead of a guided notebook-style lesson.
- LCD
- LCD stands for liquid crystal display, a screen technology that uses a backlight and liquid crystals to show images or text. It matters because LCD modules usually need a display driver and enough controller pins or a bus interface to send image data.
- microcontroller
- A microcontroller is a small computer on a chip that runs your program and controls connected inputs and outputs. For this product, it is the part that reads buttons and sensors, drives the display and speaker, and communicates over Bluetooth.
- PWM
- Pulse Width Modulation is a way for a digital pin to simulate variable output power by switching on and off very quickly. It matters for controlling things like LED brightness, motor speed, or servo-style signals from a microcontroller pin.
- RAM
- RAM is temporary memory used while a device is running, and its contents are lost when power is removed. A “Run in RAM” mode is useful for testing settings without permanently programming the module, but it may not support every feature.
- Shield
- An add-on board that plugs into a main controller board to give it extra features such as sensing, motor control or communication. Knowing a product supports shields helps you judge whether it can connect neatly into an existing maker-board setup.
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Related Tutorials
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