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Topic: Arduino Mega2560 not appearing in device manager (Read 825 times) previous topic - next topic

jzzsxm

Hi, here's my situation.  My Arduino Mega2560 used to work just skippy.  The last program I put on it was a modified "Blink" that has the delay set to 5 seconds.

Now, when I plug it into my computer, my computer simply does not see it.  The arduino turns on and the blink program runs (the pin 13 led blinks on and off every 5 seconds) but my computer doesn't show it in the device manager and doesn't even seem to know that it exists.  I can't really upgrade the drivers if I can't see the arduino with the device manager.

Any idea why this would be happening?  Any idea how to fix it?  I've tried plugging in a Duemilanove and the computer sees it and it works wonderfully.  The Mega2560 just doesn't show up.

johansson_81

it's possible that the FTDI chip is damaged, but before considering that possibility, I'd recommend you try to re-install the FT232 drivers (there is a copy in the arduino folder I believe, or you could get them from the FTDI website).

retrolefty


it's possible that the FTDI chip is damaged, but before considering that possibility, I'd recommend you try to re-install the FT232 drivers (there is a copy in the arduino folder I believe, or you could get them from the FTDI website).


The problem with your advice is that the arduino mega2560 board does not use the FTDI device nor it's driver. This board like the Uno uses the atmel 8u2 microcontroller as a USB serial converter and uses a different software driver.


James C4S

It is unlikely the FTDI chip is damaged since the Mega2560 doesn't have one.  It does, however, use an 8u2 programmed as a USB-to-Serial device.  Comparing the functionality of a Mega2560 and Duemilanove really doesn't tell you anything other than the USB ports work correctly.  It would be like saying "My Mega2560 doesn't work but my keyboard does."  In terms of USB device, the only thing the two Arduinos have in common is that they are USB devices.  They aren't the same kind of USB device.

Are you using the same cable to connect your Mega2560 and Duemilanove?  You'd be surprised how often the cable is the issue.

A trick to try is holding the ATmega in RESET while attaching the USB cable.  Press and hold the reset button, plug in the cable, see if Device Manager recognizes it.  The RESET button isn't connected to the 8u2, just the big microprocessor.

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jzzsxm

Quote
Are you using the same cable to connect your Mega2560 and Duemilanove?  You'd be surprised how often the cable is the issue.


That's why I mentioned that the Duemilanove worked, I used the same cable for both.  I also tried the trick with holding the reset button and plugging in the cable and that didn't seem to work.

gerg

#5
Jul 06, 2011, 06:35 pm Last Edit: Jul 15, 2011, 04:50 pm by gerg Reason: 1
An odd point of interest is, my mega2560 identified itself as an arduino uno until I updated the 8u2 firmware. Now it is properly identified as an arduino mega 2560. The upgrade also resolved my flashing timeouts. Special thanks to draythomp for making known a fix was readily available.
http://maniacalbits.blogspot.com

johansson_81

@retrolefty and @James C4S
In that case, sorry about the misinforming post. I'm definitely planning to go through the Mega2560 schematic again tonight to see how the Atmega8U2 is used. Could be useful for my own design work

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