[Noisebridge-discuss] Fwd: [Swarm] Arduino Mega spotted in the wild!

Christie Dudley longobord at gmail.com
Mon Mar 30 22:01:53 UTC 2009


Corey and I have been talking about going in on an order.  I was thinking
it'd be cool to see if other folks from NB wanted to get in on this too.
I'd like to get the order sent out by Thursday morning.

I've made a wiki page for signing up at:
https://www.noisebridge.net/wiki/Mega_Arduino_Order - we can do this the way
we usually do bulk orders.

---------- Forwarded message ----------
From: Corey McGuire <coreyfro at coreyfro.com>
Date: 2009/3/30
Subject: [Swarm] Arduino Mega spotted in the wild!
To: Swarm <swarm at lee.org>


Arduino Mega spotted in the wild! Who wants to jump in on an order?
Discounts at 5 and 10 http://tr.im/ardmega http://tr.im/megashield

 *$65.00, 2/$123.50, 10/$585.00, 50/$2,600.00, 100/$4,875.00*
Special Offer

   - Offer includes one FREE MEGAshield PCB per Arduino MEGA board, valued
   at $6.50 each



Arduino MEGA requires Arduino IDE 0015 or newer

Overview

The Arduino Mega is a microcontroller board based on the ATmega1280 (
datasheet <http://www.atmel.com/dyn/resources/prod_documents/doc2549.pdf>).
It has 54 digital input/output pins (of which 14 can be used as PWM
outputs), 16 analog inputs, 4 UARTs (hardware serial ports), a 16
MHzcrystal 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. The Mega is compatible with most shields
designed for the Arduino Duemilanove or Diecimila.

Schematic & Reference Design

EAGLE files: arduino-mega-reference-design.zip<http://arduino.cc/en/Main/ArduinoBoardMega?action=upload&upname=arduino-mega-reference-design.zip>
 Δ<http://arduino.cc/en/Main/ArduinoBoardMega?action=upload&upname=arduino-mega-reference-design.zip>

Schematic: arduino-mega-schematic.pdf<http://arduino.cc/en/uploads/Main/arduino-mega-schematic.pdf>
Summary



MicrocontrollerATmega1280Operating Voltage5V Input Voltage (recommended)
7-12V Input Voltage (limits)6-20V Digital I/O Pins54 (of which 14 provide
PWM output) Analog Input Pins16 DC Current per I/O Pin40 mADC Current for
3.3V Pin50 mA Flash Memory128 KB of which 4 KB used by bootloader SRAM8 KB
EEPROM4 KB Clock Speed16 MHz

Power

The Arduino Mega can be powered via the USB connection or with an external
power supply. The power source is selected automatically.

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 2.1mm
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.

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.

The power pins are as follows:

   - *VIN.* The input voltage to the Arduino board when it's using an
   external power source (as opposed to 5 volts from the USB connection or
   other regulated power source). You can supply voltage through this pin, or,
   if supplying voltage via the power jack, access it through this pin.
   - *5V.* The regulated power supply used to power the microcontroller and
   other components on the board. This can come either from VIN via an on-board
   regulator, or be supplied by USB or another regulated 5V supply.
   - *3V3.* A 3.3 volt supply generated by the on-board FTDI chip. Maximum
   current draw is 50 mA.

   - *GND.* Ground pins.

Memory

The ATmega1280 has 128 KB of flash memory for storing code (of which 4 KB is
used for the bootloader), 8 KB of SRAM and 4 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 54 digital pins on the Mega 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 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); Serial 1: 19 (RX) and 18 (TX); Serial 2: 17
   (RX) and 16 (TX); Serial 3: 15 (RX) and 14 (TX).* Used to receive (RX)
   and transmit (TX) TTL serial data. Pins 0 and 1 are also connected to the
   corresponding pins of the FTDI USB-to-TTL Serial chip.
   - *External Interrupts: 2 (interrupt 0), 3 (interrupt 1), 18 (interrupt
   5), 19 (interrupt 4), 20 (interrupt 3), and 21 (interrupt 2).* 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: 0 to 13.* Provide 8-bit PWM output with the
analogWrite()<http://arduino.cc/en/Reference/AnalogWrite>function.
   - *SPI: 50 (MISO), 51 (MOSI), 52 (SCK), 53 (SS).* These pins support SPI
   communication, which, although provided by the underlying hardware, is not
   currently included in the Arduino language. The SPI pins are also broken out
   on the ICSP header, which is physically compatible with the Duemilanove and
   Diecimila.

   - *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.
   - *I2C: 20 (SDA) and 21 (SCL).* Support I2C (TWI) communication using the
   Wire library
<http://wiring.org.co/reference/libraries/Wire/index.html>(documentation
on the Wiring website). Note that these pins are not in the
   same location as the I2C pins on the Duemilanove or Diecimila.

The Mega has 16 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 analogReference() function.


There are a couple of other pins on the board:

   - *AREF.* Reference voltage for the analog inputs. Used with
   analogReference <http://arduino.cc/en/Reference/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.

Communication

The Arduino Mega has a number of facilities for communicating with a
computer, another Arduino, or other microcontrollers. The
ATmega1280provides four hardware
UARTs for TTL (5V) serial communication. An FTDI FT232RL on the board
channels one of these over USB and the FTDI
drivers<http://www.ftdichip.com/Drivers/VCP.htm>(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. 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
<http://www.arduino.cc/en/Reference/SoftwareSerial>allows for serial
communication on any of the Mega's digital pins.

The ATmega1280 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<http://wiring.org.co/reference/libraries/Wire/index.html>for
details. To use the SPI communication, please see the
ATmega1280 datasheet.

Programming

The Arduino Mega can be programmed with the Arduino software
(download<http://arduino.cc/en/Main/Software>).
For details, see the reference <http://arduino.cc/en/Reference/HomePage> and
tutorials <http://arduino.cc/en/Tutorial/HomePage>.

The ATmega1280 on the Arduino Mega comes preburned with a
bootloader<http://arduino.cc/en/Tutorial/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 <http://www.atmel.com/dyn/resources/prod_documents/doc2525.pdf>, C
header files <http://www.atmel.com/dyn/resources/prod_documents/avr061.zip>
).

You can also bypass the bootloader and program the microcontroller through
the ICSP (In-Circuit Serial Programming) header; see these
instructions<http://arduino.cc/en/Hacking/Programmer>for details.
Automatic (Software) Reset

Rather then requiring a physical press of the reset button before an upload,
the Arduino Mega 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 ATmega1280 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 Mega 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 Mega. 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.

The Mega contains a trace that can be cut to disable the auto-reset. The
pads on either side of the trace can be soldered together to re-enable it.
It's labeled "RESET-EN". You may also be able to disable the auto-reset by
connecting a 110 ohm resistor from 5V to the reset line; see this forum
thread <http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1213719666/all> for
details.
USB Overcurrent Protection

The Arduino Mega 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 and Shield Compatibility

The maximum length and width of the Mega PCB are 4 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.

The Mega is designed to be compatible with most shields designed for the
Diecimila or Duemilanove. Digital pins 0 to 13 (and the adjacent AREF and
GND pins), analog inputs 0 to 5, the power header, and ICSP header are all
in equivalent locations. Further the main UART (serial port) is located on
the same pins (0 and 1), as are external interrupts 0 and 1 (pins 2 and 3
respectively). SPI is available through the ICSP header on both the Mega and
Duemilanove / Diecimila. *Please note that I2C is not located on the same
pins on the Mega (20 and 21) as the Duemilanove / Diecimila (analog inputs 4
and 5).*

Images

Some images contain optional accessories and components.

          Related items
<http://www.nkcelectronics.com/arduino-diecimila.html> Arduino
Duemilanove<http://www.nkcelectronics.com/arduino-diecimila.html>

Price: $29.45
<http://www.nkcelectronics.com/seeeduino-fully-assembled--arduino-compatible.html>
Seeeduino
fully Assembled - Arduino
compatible<http://www.nkcelectronics.com/seeeduino-fully-assembled--arduino-compatible.html>

Price: $23.99


---- SWARM, A Large Scale Kinetic Art Project
---- http://orbswarm.com http://lists.lee.org/listinfo.cgi/swarm-lee.org



-- 
I refuse to give up childish things.
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