Arduino Mega 2560 R3 not visible to the PC

Hi,

I recently purchased an Arduino Mega 2560 R3 and was working fine for a couple of days.
I expanded the blink sketch to do a knight rider effect with more Led's
This worked ok and the sketch runs.
When I went to upload a modified sketch to light 2 led's instead of one the upload failed.
The com port com5 was not on the serial port list.
I restarted the software, pc, arduino and nothing.
I checked the device manager and my com5 was gone.
When I reconnect the arduino windows does show any new devices, nothing changes as If I had not plugged it in.
There are no unkown devices or other devices in my devie list either.
The sketch that I las upload is still running happily and the power is coming from the USB.

I have read in another post about putting the arduino into DFU mode and uploading the firmware.
I have tried the several suggestions but most are aimed at earlier versions of the Mega or the uno.
There are no specific instructions of how to put the R3 into DFU.

I don't think it is in dfu at the moment as it does not show up as a dfu device in my drivers.
I have also tried plugging it into other pc's and they dont "see" it either.

I had previously posted on another post but only realised that was for the uno and not the mega so I's creating a new post. The uno one was http://arduino.cc/forum/index.php/topic,123804.0.html

Any help would be appreciated.

Albert Pizzarello

Try this IDE enhanced:
http://arduino.cc/forum/index.php/topic,118440.0.html

It will more than likely move the com port, but I am curious if this is a good solution to this chronic problem.

Hi,

Thanks for the suggestion, I have tried it but it still does not find the card.

Bottom line is that the PC does not "see" it when plugged in, its like the usb part of the arduino is not working at all, although the usb still powers the card.

Albert

Do you have another cable to test with? Also, do you have a second Arduino device?

Thanks for the suggestion, I have tried it but it still seem error.

Hi,

I have tried another cable and also I do not have another Arduino.

I have just ordered a UNO then I will send back the mega to get replaced.

Is there a way to use the uno to diagnose/repair the mega?

If I don't need to send it back all the better.

Albert

Once you get the Uno, we can turn it into a programmer (Arduino as ISP) and with a few AVRDUDE commands we could re-flash the 16u2. Since you are getting absolutely nothing showing on your USB Bus (PC side) the Atmel FLIP is worthless.

Anyhow, if you copy the atmega16u2-usbserial hex file and paste it in the AVRDUDE directory you could re-flash it with the "Non-combined" hex, which I suspect is an issue. I used this for my Uno R3:

avrdude -p at90usb162 -F -P usb -c arduino -U flash:w:Ardu
ino-usbserial-uno.hex -U lfuse:w:0xEF:m -U hfuse:w:0xD9:m -U efuse:w:0xF4:m -U l
ock:w:0x0F:m

Worked flawlessly.

Unfortunately, my "Mega" is an R2 with the Atmega8u2, so I can not test the "robustness" of usbserial only hex.

Anyhow, if you wish, we could attempt the re-flashing when your Uno gets in.

Hi,

Sounds great.

Can you point me to any info regarding the cables etc I will require. So I can start getting something knocked up.

I will be getting my uno 26th Sep.

Will get in contact for advice once I get it.

Albert

You will need something to get on that 2x3 male header next to the USB port. It is the In Circuit System Programmer (ICSP) for the 8u2/16u2 chip that handles the USB2TTL communications to the Atmega2560. If you have (6) female/male jumpers or a 2x3 ribbon cable and (6) male/male jumpers, that should work. Then we just plug it into the 5v/Gnd and D10-D13 of the Arduino (loaded with Arduino as ISP sketch). Viola, you are ready to program AVR chips

This is something no automated driver installer will even be able to fix =(

It is your Arduino a clone? I think the clones are the guilty guys here.

Hi,

Spcomputing thanks for the info.

And its not a clone, purchased from Cooking Hacks in Barcelona. Who are an offical supplier.

BTW They are a good/fast supplier, with good after sales support.

Albert

SpyderManGib:
Hi,

Spcomputing thanks for the info.

And its not a clone, purchased from Cooking Hacks in Barcelona. Who are an offical supplier.

BTW They are a good/fast supplier, with good after sales support.

Albert

Maybe you can return the board for a replacement?

Hi,

I probably will, but if I can use the uno to fix the 2560 then I will certainly try.

Albert

Hi,

Spcomputing thanks for the info.

No problem. Programming the 16u2 will be fun skill to learn and if it doesn't work, then return it...

I received the UNO and that works straight away on my PC so the MEGA is 100% faulty.

I connected the two via the manual method of using the wires.
I was able to upload a sketch to the mega via the UNO.

But I got cold feet in going further as I was worried that I could inadvertently program the UNO with the MEGA'S Firmware.

I decided to just send it back for replacement.

Albert

Aawww... thats okay. I would do the same if the turnout policy is like that shipped Uno

Good luck!

Hello. I have the same problem. I received my r3 board from ebay few month ago. I had no time to test it. Now I bought the USB cable. It powers from USB. Blinks all the time but no of 4 windows or linux PC see it. Tried another cable- doesn't help. I have Uno v3 and Nano boards.

Can somebody point me to tutorial how to check/fix atmega16u2 usbserial?

I can't send it back as i lost seller contacts ;( don't want to send it to trash too.

If there can be nothing done to 16u2 chip is there any other hardware easy way to solve the isue? I mean any cheap external usb to serial shilds which are suitable for mega?
Please help!