Arduino Uno R3

The Arduino Uno is an 8-bit microcontroller board based on the ATmega328 chip (see the datasheet). It has 14 digital input/output pins (6 of these can also utilize the ADC onboard for PWM), 6 analog inputs, a 16 MHz ceramic resonator, a USB Type-B connector, a DC Barrel jack for power, an ICSP header and a reset button on board! It contains everything needed to support the microcontroller.

"Uno" means one in Italian and is this board was named as such to mark the then upcoming release of The Arduino IDE 1.0. The Uno and version 1.0 are the current reference versions of Arduino. The Uno is the easily the most popular Arduino Board, being featured in almost every microcontroller beginner kit with Arduino products in them.

Features

ATMega328P Processor

Memory

• AVR CPU at up to 16 MHz
• 32 kB Flash
• 2 kB SRAM
• 1 kB EEPROM

Security

• Power On Reset (POR)
• Brown Out Detection (BOD)

Peripherals

• 2x 8-bit Timer/Counter with a dedicated period register and compare channels
• 1x 16-bit Timer/Counter with a dedicated period register, input capture and compare channels
• 1x USART with fractional baud rate generator and start-of-frame detection
• 1x controller/peripheral Serial Peripheral Interface (SPI)
• 1x dual-mode controller/peripheral I2C
• 1x Analog Comparator (AC) with a scalable reference input
• Watchdog Timer with separate on-chip oscillator
• Six PWM channels
• Interrupt and wake-up on pin change

ATMega16U2 Processor

• 8-bit AVR® RISC-based microcontroller

Physical Characteristics

• Maximum PCB dimensions: 68.6 mm long × 53.3 mm wide
• Spacing between digital pins 7 and 8: 4.06 mm
• Standard spacing between the other pins: 2.54 mm

Memory

• 16 kB ISP Flash
• 512 B EEPROM
• 512 B SRAM
• debugWIRE interface for on-chip debugging and programming

Power

• 2.7–5.5 V

Input and Output

Each of the 14 digital pins on the Uno uses 5V logic. 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. Control of the nature of each pin takes place within the IDE.

Some of the IO pins have extra functionality:

• Serial: 0 (RX) and 1 (TX). Used to receive (RX) and transmit (TX) TTL serial data. These pins are connected to the corresponding pins of the ATmega8U2 USB-to-TTL Serial chip.
• External Interrupts: 2 and 3. These pins can be configured to trigger an interrupt on a low value, a rising or falling edge, or a change in value. See the attachInterrupt() function for details.
• PWM: 3, 5, 6, 9, 10, and 11. Provide 8-bit PWM output with the analogWrite() function.
• SPI: 10 (SS), 11 (MOSI), 12 (MISO), 13 (SCK). These pins support SPI communication using the SPI library.
• LED: 13. There is a built-in LED connected to digital pin 13. When the pin is HIGH value, the LED is on, when the pin is LOW, it's off. The Uno has 6 analog inputs, labeled A0 through A5, each of which provides 10 bits of resolution (i.e. 1024 different values). By default they measure from ground to 5 volts, though is it possible to change the upper end of their range using the AREF pin and the analogReference() function. Additionally, some pins have specialized functionality:
• TWI: A4 or SDA pin and A5 or SCL pin. Support TWI communication using the Wire library. There are a couple of other pins on the board:
• AREF. The reference voltage for the analog inputs. Used with analogReference().
• Reset. Bring this line LOW to reset the microcontroller. Typically used to add a reset button to shields which block the one on the board.

Shipping List

• Official Arduino Uno R3
• Plastic Uno Mount
• Arduino Sticker Sheet

Related Documents

• Pinout
• Datasheet
• Schematics
• CAD Files