Arduino
Diecimila
The Arduino Diecimila is an open-source physical computing platform based on a simple i/o
board 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).
It is a
microcontroller board based on the ATmega168 (datasheet). It has 14 digital
input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs,
a 16 MHz crystal oscillator, a USB connection, a power jack, an ICSP header,
and a reset button. It contains everything needed to support the
microcontroller; simply connect it to a computer with a USB cable or power
it with a AC-to-DC adapter or battery to get started.
"Diecimila" means 10,000 in Italian and was named thusly to mark the fact
that over 10,000 Arduino boards have been made. The Diecimila is the latest
in a series of USB Arduino boards; for a comparison with previous versions,
see the index of Arduino boards.
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Summary
Microcontroller ATmega168
Operating Voltage 5V
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 6
DC Current per I/O Pin 40 mA
Flash Memory 16 KB (of which 2 KB used by bootloader)
SRAM 1 KB
EEPROM 512 bytes
Clock Speed 16 MHz
Memory
The ATmega168 has 16 KB of flash memory for storing code (of which 2 KB is
used for the bootloader). It has 1 KB of SRAM and 512 bytes of EEPROM (which
can be read and written with the EEPROM library).
Programming
The Arduino Diecimila can be programmed with the Arduino software
(download). For details, see the reference and tutorials.
The ATmega168 on the Arduino Diecimila 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 ATmega168 through the
ICSP (In-Circuit Serial Programming) header; see these instructions for
details.
Automatic (Software) Reset
Rather then requiring a physical press of the reset button before an upload,
the Arduino Diecimila 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 ATmega168
via a 100 nanofarad capacitor. When this line is asserted (taken low), the
reset line drops long enough to reset the chip. Version 0009 of 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 Diecimila 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 Diecimila. 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.
Input and Output
Each of the 14 digital pins on the Diecimila can be used as an input or
output. 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. Pins 3, 5, 6, 9, 10, and 11 can provide PWM output; for details
see the analogWrite() function. If anything is connected to pins 0 and 1, it
will interfere with the USB communication, preventing new code from being
uploaded or other communication with the computer.
The Diecimila has 6 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 AREF pin and some low-level code.
See also the mapping between Arduino pins and ATmega168 ports.
Communication
The Arduino Diecimila has a number of facilities for communicating with a
computer, another Arduino, or other microcontrollers. The ATmega168 provides
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 Arduino
software) provide a virtual com port to software on the computer. The
Arduino software includes a serial monitor which allows simple textual data
to be sent to and from the Arduino board.
A SoftwareSerial library allows for serial communication on any of the
Diecimila's digital pins.
The ATmega168 also supports I2C (TWI) and SPI communication. The Arduino
software includes a Wire library to simplify use of the I2C bus; see the
documentation on the Wiring website for details. To use the SPI
communication, please see the ATmega168 datasheet.
Power
The Arduino Diecimila can be powered via the USB connection or with an
external power supply. The power source is selected by the PWR_SEL jumper:
to power the board from the USB connection, place it on the two pins closest
to the USB connector, for an external power supply, the two pins closest to
the external power jack.
External (non-USB) power can come either from an AC-to-DC adapter
(wall-wart) or battery. The adapter can be connected by plugging a center-positive
plug into the board's power jack. Leads from a battery can be inserted in
the Gnd and Vin pin headers of the POWER connector. A low dropout regulator
provides improved energy efficiency.
The board can operate on an external supply of 6 to 20 volts. If supplied
with less than 7V, however, the 5V pin may supply less than five volts and
the board may be unstable. If using more than 12V, the voltage regulator may
overheat and damage the board. The recommended range is 7 to 12 volts.
USB Overcurrent Protection
The Arduino Diecimila has a resettable polyfuse that protects your
computer's USB ports from shorts and overcurrent. Although most computers
provide their own internal protection, the fuse provides an extra layer of
protection. If more than 500 mA is applied to the USB port, the fuse will
automatically break the connection until the short or overload is removed.
Physical Characteristics
The maximum length and width of the Diecimila PCB are 2.7 and 2.1 inches
respectively, with the USB connector and power jack extending beyond the
former dimension. Three screw holes allow the board to be attached to a
surface or case. Note that the distance between digital pins 7 and 8 is 160
mil (0.16"), not an even multiple of the 100 mil spacing of the other pins.
Have a look at our other Arduino Compatible Cards
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