The Arduino Nano is a DIP module that features an ATmega328 microcontroller and an FTDI USB-to-serial converter chip connected to a mini-USB connector. This ATmega328 DIP module features two single rows of male header pins (0.1" spacing, 0.6" wide), on the bottom that allow it to be inserted into solderless breadboards for easy access to and wiring of all ATmega328 pins.
This ATmega328 board is pre-programmed with the Arduino bootloader that allows you to upload code to the ATmega328 via USB using the open-source Arduino development environment.
|Microcontroller ||Atmel ATmega328 |
|Operating Voltage (logic level) ||5 V |
|Input Voltage (recommended) ||7-12 V |
|Input Voltage (limits) ||6-20 V |
|Digital I/O Pins ||14 (of which 6 provide PWM output) |
|Analog Input Pins ||8 |
|DC Current per I/O Pin ||40 mA |
|Flash Memory ||32 KB (of which 2KB used by bootloader) |
|SRAM ||2 KB |
|EEPROM ||1 KB |
|Clock Speed ||16 MHz |
|Dimensions ||0.73 x 1.70 in. |
Arduino Nano Features
- Automatic reset during program download
- Power OK blue LED on the bottom
- Green (TX), red (RX) and orange (L) LED
- +5V to AREF jumper
- Auto-sensing/switching power input
- Small mini-B USB for programming and serial monitor
- ICSP header for direct program download
- Standard 0.1 spacing DIP (breadboard friendly)
- Manual reset switch
Power The Arduino Nano can be powered via the mini-B USB connection, 6-20V unregulated external power supply (pin 30), or 5V regulated external power supply (pin 27). The power source is automatically selected to the highest voltage source.
The FTDI FT232RL chip on the Nano is only powered if the board is being powered over USB. As a result, when running on external (non-USB) power, the 3.3V output (which is supplied by the FTDI chip) is not available and the RX and TX LEDs will flicker if digital pins 0 or 1 are high.
Memory The ATmega328 on the Nano has 32 KB of flash memory for storing code (of which 2 KB is used for the bootloader). It has 2 KB of SRAM and 1 KB of EEPROM (which can be read and written with the EEPROM library).
Input and Output Each of the 14 digital pins on the Nano can be used as an input or output, using 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:
- 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 FTDI 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, which, although provided by the underlying hardware, is not currently included in the Arduino language.
- 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 Nano has 8 analog inputs, each of which provide 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 analogReference() function. Additionally, some pins have specialized functionality:
- I2C: 4 (SDA) and 5 (SCL). Supports I2C (TWI) communication using the Wire library (documentation on the Wiring website).
There are a couple of other pins on the board:
- AREF. 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.
See also the mapping between Arduino pins and ATmega328 ports reference.
Programming The Arduino Nano can be programmed with the Arduino software (download). For details, see the Arduino Reference and Basic Concepts.
The ATmega328 on the Arduino Nano 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 original STK500 protocol (reference, C header files).
You can also bypass the bootloader and program the ATmega328 through the ICSP (In-Circuit Serial Programming) header. See these instructions for details.
Automatic (Software) Reset Rather than requiring a physical press of the reset button before an upload, the Arduino Nano is designed in a way that allows it to be reset by software running on a connected computer. One of the hardware flow control lines (DTR) of the FT232RL is connected to the reset line of the ATmega328 via a 100-nanofarad capacitor. When this line is asserted (taken low), the reset line drops long enough to reset the chip. The Arduino software uses this capability to allow you to upload code by simply pressing the upload button in the Arduino environment. This means that the bootloader can have a shorter timeout, as the lowering of DTR can be well-coordinated with the start of the upload.
This setup has other implications. When the Nano is connected to either a computer running Mac OS X or Linux, it resets each time a connection is made to it from software (via USB). For the following half-second or so, the bootloader is running on the Nano. While it is programmed to ignore malformed data (i.e. anything besides an upload of new code), it will intercept the first few bytes of data sent to the board after a connection is opened. If a sketch running on the board receives one-time configuration or other data when it first starts, make sure that the software with which it communicates waits a second after opening the connection and before sending this data.
Arduino is an open-source platform based on boards featuring an Atmel AVR microcontroller with a pre-programmed bootloader and a development environment that implements the Processing / Wiring language. Arduino can be used to develop stand-alone interactive objects or can be connected to software on your computer (e.g. Flash, Processing, MaxMSP). The open-source IDE can be downloaded for free (currently for Mac OS X, Windows, and Linux).
Arduino Nano Downloads
Optional Recommended Products for this Item