A000066 Arduino, A000066 Datasheet - Page 3

• Manufacturer Part Number: A000066
• Description: Development Boards & Kits - AVR ARDUINO UNO REV 3
• Manufacturer: Arduino

Specifications of A000066

• Rohs: yes
• Product: Development Kits
• Tool Is For Evaluation Of: ATmega328P
• Core: AVR8
• Interface Type: I2C, ICSP, SPI, USB
• Data Bus Width: 8 bit
• For Use With: ATmega

The Uno has 6 analog inputs, labeled A0 through A5, 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
the analogReference() function. Additionally, some pins have specialized functionality:
There are a couple of other pins on the board:
See also the
Communication
The Arduino Uno has a number of facilities for communicating with a computer, another Arduino, or other microcontrollers. The
ATmega328 provides UART TTL (5V) serial communication, which is available on digital pins 0 (RX) and 1 (TX). An ATmega16U2 on
the board channels this serial communication over USB and appears as a virtual com port to software on the computer. The '16U2
firmware uses the standard USB COM drivers, and no external driver is needed. However,
Arduino software includes a serial monitor which allows simple textual data to be sent to and from the Arduino board. The RX and
TX LEDs on the board will flash when data is being transmitted via the USB-to-serial chip and USB connection to the computer (but
not for serial communication on pins 0 and 1).
A
The ATmega328 also supports I2C (TWI) and SPI communication. The Arduino software includes a Wire library to simplify use of the
I2C bus; see the
Programming
The Arduino Uno can be programmed with the Arduino software (download). Select "Arduino Uno from the Tools > Board menu
(according to the microcontroller on your board). For details, see the
The ATmega328 on the Arduino Uno comes preburned with a
an external hardware programmer. It communicates using the original STK500 protocol (reference,
You can also bypass the bootloader and program the microcontroller through the ICSP (In-Circuit Serial Programming) header; see
these instructions
The ATmega16U2 (or 8U2 in the rev1 and rev2 boards) firmware source code is available . The ATmega16U2/8U2 is loaded with a
DFU bootloader, which can be activated by:
You can then use
can use the ISP header with an external programmer (overwriting the DFU bootloader). See
information.
Automatic (Software) Reset
Rather than requiring a physical press of the reset button before an upload, the Arduino Uno 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 ATmega8U2/16U2 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
SoftwareSerial library
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
PWM: 3, 5, 6, 9, 10, and 11. Provide 8-bit PWM output with the
SPI: 10 (SS), 11 (MOSI), 12 (MISO), 13 (SCK). These pins support SPI communication using the
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.
TWI: A4 or SDA pin and A5 or SCL pin. Support TWI communication using the
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.
On Rev1 boards: connecting the solder jumper on the back of the board (near the map of Italy) and then resetting the 8U2.
On Rev2 or later boards: there is a resistor that pulling the 8U2/16U2 HWB line to ground, making it easier to put into DFU
mode.
mapping between Arduino pins and ATmega328
documentation
Atmel's FLIP software
for details.
allows for serial communication on any of the Uno's digital pins.
for details. For SPI communication, use the
attachInterrupt()
(Windows) or the
function for details.
DFU programmer
ports. The mapping for the Atmega8, 168, and 328 is identical.
bootloader
reference
analogWrite()
that allows you to upload new code to it without the use of
(Mac OS X and Linux) to load a new firmware. Or you
SPI
and tutorials.
library.
function.
Wire
on Windows, a .inf file is
library.
this user-contributed tutorial
C header
SPI
files).
library.
required. The
for more