Hi all!  I have built the circuit from here:http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1230333861/15 -

And it works, except for then the dimming value gets low.  It works great when close to 100 (dim)  to 30 (75% bright)  range, but it stays at about 75% bright all the way down to a value of 0.  If I just turn the Arduino pin to HIGH, then I do get full brightness. 

Any ideas?  I have checked and rechecked my layout and it seems like if there was a wiring problem it just wouldn't work at all.

I just uploaded the new IDE.  I thought there were no problems, but when I try to verify a program using the CmdMessenger library, I get an error that says :

/Applications/Arduino.app/Contents/Resources/Java/libraries/CmdMessenger/CmdMessenger.h:86: error: 'boolean' does not name a type

I checked it on my Mac and a Windows machine with the same error....any ideas?

I changed the baud rate from 115200 to 9600 and it worked without any other modification.  No idea why the 328 Atmega chip worked at the higher rate,but the Mega 2560 did not????

I tested the netbook and the Mega shows on com port 4 - I can access the Mega on the netbook just fine.  But when i run the communication program - no communication.  The 328 chip/board works just fine....

puzzled......

I believe that com port 4 is mapped, because I can download programs to the Mega using the Arduino IDE.  I can also use the IDE for serial communication back and forth via the USB cable.

I have it connected with a USB cable, and am using CMD messenger library on the Arduino side.  The netbook side has serial send and receive commands much like the Arduino.

Still puzzled
Charles

I am working on a robot project.  I am using a little Asus netbook as the main brain, and an Arduino for gathering data and interfacing with motors.

I am using a great program called Robot See.  The program interfaces fine with an Arduino 328 - I found it is using com port 3.  But I want to interface with a Mega.  NO GO.

I can use the Arduino IDE and upload programs to the Mega.  I can use the serial monitor with the Mega and Arduino IDE and it works.  I found that it is connecting on com port 4.  But when I connect it to the netbook and change the com port to 4 - it acts like there is no communication.

The netbook is using simple serial communication.

Any ideas why the Mega won't work when the 328 chip/module does?

cheers
Charles

Thanks - even the Arduino official site says that the solder pads are next to the map of Italy silkscreened on the back of the board.  I really appreciate your clear and concise tutorial.

I have looked at a lot of posts, but don't see an image or description of where the location of the pin to short to ground is.  It looks like the group of 6 pins near the usb port is the same as on the UNO, but I can't figure out where the two pins in the UNO illustration are on the MEGA.

I am having problems with the Mega 2560.  It will sometimes let me upload programs several times, but usually I have to shut down the IDE, disconnect the board, reconnect it, start up the IDE and then get one good upload and do the whole thing all over again...and often I still can't get it to upload even then.  I can get one successful upload out of maybe 15 or 20 tries.

Any ideas on the error code from terminal?

Thanks for the tutorial!  It is great!!!!!!!!!!!!!!!

OOPs - assuming I can get it working, is the 10K resistor necessary for the mega 2560?

I have an old eMac running 10.5.  I successfully got macports to install.  In terminal I typed in your command and put in the password for sudo.

But now an error:
Warning: no index(es) found. have you synced your source indexes?
error: Port dfu-programmer not found.

Any words of wisdom?

THANKS - I just found a link that steps you through installing the dfu program:
https://alliance.seas.upenn.edu/~medesign/wiki/index.php/Guides/MaEvArM-starting-mac
But it needs a much higher level of OSX than I can run on my old machine!
I am still looking.....

OK - sorry I have no experience with the dfu program or with working with the chips and re-flashing.  I can do programming and have been doing that for a couple of years.

So I don't understand the dfu utility.  I downloaded it and the hex file as in the instructions.  But I don't know how to get the dfu programming software to work!

My Mega 2560 will occasionally upload a sketch, but maybe once every 20 tries.  I am guessing it's the re-flash problem.  I've read the old posts, but I can't figure out how to get the dfu running so I can give the commands listed on the post.

This is very, very frustrating!  I am using an old Mac running 10.4 and the newest IDE 22 and I just uploaded dfu-programmer 0.5.2

Help?

Thank you Mikalhart.  You were exactly right. I studied the PROGMEM information and now I have placed all of my control strings into flash memory.  The program seems to be working like a charm.  Thank you so much for your help.

I wondered about memory.  However, the only data I'm using is about 3 dozen lines like:
Serial.println("#1 P1500 #4 P1500 #8 P1500 T1000 <cr>");

ALSO - weirdly I retyped the program thinking i had a control character or the like somewhere.  When I got to around 3500 bytes I couldn't add the next routine.  Then I switched to the older 009 version of the compiler and it compiled and ran correctly.  But now I can't add any more code.

If it is memory, can I change the commands to strings or something?

Thanks