Memory; Input And Output; Communication - Arduino ArduinoBoardFio Quick Start Manual

- BAT. For supplying a Lithium Polymer battery to the board.
- 3V3. The regulated 3.3 volt supply pins.
- GND. Ground pins.

Memory

The ATmega328P 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 (http://www.arduino.cc/en/Reference/EEPROM)).

Input and Output

Each of the 14 digital pins on the Fio can be used as an input or output, using pinMode() (http://arduino.cc/en/Reference/PinMode),
digitalWrite() (http://arduino.cc/en/Reference/DigitalWrite), and digitalRead() (http://arduino.cc/en/Reference/DigitalRead)
functions. They operate at 3.3 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: RXI (D0) and TXO (D1). Used to receive (RX) and transmit (TX) TTL serial data. These pins are connected to the DOUT and DIN pins of the XBee
modem socket.
- 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() (http://arduino.cc/en/Reference/AttachInterrupt) function for details.
- PWM: 3, 5, 6, 9, 10, and 11. Provide 8-bit PWM output with the analogWrite() (http://arduino.cc/en/Reference/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 Fio has 8 analog inputs, each of which provide 10 bits of resolution (i.e. 1024 different values). The analog inputs measure from
ground to Vcc. Additionally, some pins have specialized functionality:
- I C: 4 (SDA) and 5 (SCL). Support I
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There are couple of another pins on the board:
AREF. Reference voltage for the analog inputs. Used with analogReference() (http://arduino.cc/en/Reference/AnalogReference).
-
- DTR. Bring this line LOW to reset the microcontroller. Typically used to add a reset button to shields which block the one on the board.
There are also 8 unsoldered holes on the board:
- BAT + and BAT -. To be connected to a battery. Typically used when you don't want to connect a battery to the battery connector.
- CHG 5V and CHG -. To be connected to charging terminals. Typically used to add an external connector for charging.
- SW. Connected to the power switch on the board. Typically used to add an external power switch.
- CTS. Connected to the #CTS/DIO7 pin of the XBee socket. Typically used to do sleep control for a XBee modem.
DTR. Connected to the #DTR/SLEEP_RQ/DI8 pin of the XBee socket. Typically used to do sleep control for a XBee modem.
-
See also the mapping between Arduino pins and ATmega328P ports (http://arduino.cc/en/Hacking/PinMapping168).

Communication

The Arduino Fio has a number of facilities for communicating with a computer, another Arduino, or other microcontrollers. The
ATmega328P provides UART TTL serial communication, which is available on digital pins 0 (RX) and 1 (TX). The Arduino software
includes a serial monitor which allows simple textual data to be sent to and from the Arduino Fio board via an external serial
connection. We recommend using an FTDI Basic or FTDI cable. The on board mini-USB connector is only used for charging and does not
allow for serial communication.
A SoftwareSerial library (http://www.arduino.cc/en/Reference/SoftwareSerial) allows for serial communication on any of the Fio's
digital pins.
The ATmega328P also supports I2C (TWI) and SPI communication. The Arduino software includes a Wire library to simplify use of the
I2C bus; see the reference (http://arduino.cc/en/Reference/Wire) for details. To use the SPI communication, please see the
ATmega328P datasheet.
C (TWI) communication using the Wire library (http://arduino.cc/en/Reference/Wire).
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