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 DFRduino 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). Support 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 DFRduino pins and ATmega168 ports.

Communication

The DFRduino Nano has a number of facilities for communicating with a computer, another

DFRduino, or other microcontrollers. The ATmega168 and ATmega328 provide UART TTL (5V)

serial communication, which is available on digital pins 0 (RX) and 1 (TX). An FTDI FT232RL on the

board channels this serial communication over USB and the FTDI drivers (included with the

DFRduino software) provide a virtual com port to software on the computer. The DFRduino software

includes a serial monitor which allows simple textual data to be sent to and from the DFRduino

board. The RX and TX LEDs on the board will flash when data is being transmitted via the FTDI chip

and USB connection to the computer (but not for serial communication on pins 0 and 1).

A SoftwareSerial library allows for serial communication on any of the Nano's digital pins.

The ATmega168 and ATmega328 also support I2C (TWI) and SPI communication. The DFRduino

software includes a Wire library to simplify use of the I2C bus; see the documentation for details. To

use the SPI communication, please see the ATmega168 or ATmega328 datasheet.

Programming

The DFRduino Nano can be programmed with the DFRduino software (download). Select

"DFRduino Diecimila, Duemilanove, or Nano w/ ATmega168" or "DFRduino Duemilanove or Nano

w/ ATmega328" from the Tools > Board menu (according to the microcontroller on your board). For

details, see the reference and tutorials.