Arduino Mega 2560 will not run Blink.ino

Hey all,

I have an Arduino Duemilanove and an Arduino Mega 2560. Up until today, both have always worked fine. I've been working on a project over the past few days, but when I plugged in the Mega today, it just would not run the sketch I had been working on.

The sketch uploads (pin 13, RX and TX LED's flash in the usual pattern), and the Arduino IDE says "Done Uploading" with no errors. I went back and tried the Blink.ino example sketch, and even that doesn't work. As above, the upload seems to go fine, based on the LED's and message in the IDE. If I manually reset the Arduino after uploading by pressing the reset button, I get the usual two blinks on pin 13, then nothing after that. As far as I can tell, the sketch just will not run. I also tried the BlinkWithoutDelay example, and got the same results.

To check that the IDE and my computer were fine, I uploaded the Blink sketch to my Duemilanove, and it runs fine there - pin 13 is blinking away happily on the Duemilanove. I also verified the serial connection to the Mega with the loop-back test from,73748.0.html.

Something I noticed, is that if I open the Serial Monitor from the IDE when the Arduino Mega is plugged in, pin 13 lights up and stays lit until I close the Serial Monitor. Odd, since it should be blinking according to the Blink.ino sketch, whether the Serial Monitor is open or not. Not sure what this means.

More info: -Windows 7 64-bit -Arduino 1.0 IDE -Arduino Mega 2560 R2 -Yes, I have the proper board ("Arduino Mega 2560 or Mega ADK") and serial port selected in the Tools menu. -No external circuitry or wires connected aside from the USB cable

Anybody have an idea of what is causing this issue? I am inclined to believe that the bootloader is OK, because the upload appears to be working. I would say that I'm fairly experienced with Arduino, but this is something I've never seen before.

Thanks, -Bob

Still not sure what the issue was, but I downloaded the newest version of the Arduino IDE (switched from 1.0 to 1.0.1), and my Mega seems to be working OK now. Hope that helps anybody else with the same issue. Cheers, -Bob

Scratch that… issue just showed up again.

I had done several cycles of code work, upload, test, repeat, and all was going well. Uploads were going fine, and the Arduino Mega was running the code just fine.
Then out of the blue, the same symptoms from the first post above showed up again. The only thing I could think of was that a mistake in my code had caused the issue, so I went back and uploaded the last known working version of the code to the Mega. Unfortunately, the issue persisted. Then I re-installed the Arduino IDE, because that seemed to fix the issue last time - not this time though. I’m back where I started here, completely clueless.

Anybody have ideas? Thanks!

Hi sentryGun 53, did you ever work out the cause of permanent light on LED13 on the Mega 2560? I'm having trouble uploading sketches to my Mega 2560 and the only diagnostic I have to work with is the fact that this LED is permanently on. What does it mean?

There is something with 1.0 and the mega, I had those issues too.