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Topic: Shield made by me makes arduino unrecognized to PC (Read 863 times) previous topic - next topic


Hy i have an arduino duemilanove with ATMEGA 328P and i have a shield connected him but it give me an error on the PC saying that windows does not recognize the USB device and the RX and TX leds do not turn off unless I remove the shield and connect the arduino without the shield .... so he can already recognize the device that I built to arduino work properly.
nobody is aware of the problem?I have looked in forums and I can not find anyone with this problem...
please help me, I would apreciate a lot...


Does your shield connect to pins 0 and 1 (the TX and RX pins)? If so, then the shield WILL interfere with the computer's ability to interact with the Arduino.
The art of getting good answers lies in asking good questions.


Aug 09, 2010, 05:04 pm Last Edit: Aug 09, 2010, 05:30 pm by mig@lh@s Reason: 1
No, nothing like that .. The only Pins that are in use are pins 2, 4 and 7 for input, 5V and GND ... I did not connect anything to pins 0 and 1 already because of this situation ..my shiled is this

The shield is connected to arduino pins with the match between them but I only use 5 pins and neither of them is the O/1 RX/TX.

P.S. the arduino work properly without the shield but if I connect the PC with the arduino shield in place it lights up the arduino RX and TX leds and not recognize the card, but if I connect the Arduino to the USB and only afterarduino being recognized I connect the shield on top of the Arduino and it works correctly ... are you understand me?


First off please do not cross post on this forum, it gets people very angry.

Check that the shield isn't shorting out the power with a small sliver of copper between power  (+5v) and ground.


sorry I don't know what it means...do not cross post on this forum?explain me please...
and thanks for the replys...


Cross-posting generally means posting the same topic in several different locations.

Please check for a short betweeen +5V and GND like Mike said.  While you're at it, please check if the Power LED is on on the board.  My computer shuts off ports drawing >500mA, causing that LED to turn off.  I don't know if yours does this, but it's worth checking.


ow sorry for the cross post but I start a post in a subject and after one or two replys they tell-me to change the post to another subject...
I think that the board haven't any short-circuit and the PWR led is always on except when I turn off the arduino...its really strange because the two boards work well but can not be connected with the boards connected to each other, I have to connect the arduino to PC USB and then connect the shield board to arduino....It's not necessary to do a chante anywere?


Long shot here, but what was the last sketch loaded on the Arduino? Make sure you load a sketch that won't interfere with anything; the Blink sketch will do for this board...

I'm thinking weird things like your analog inputs set to digital outputs or something causing an issue. Also, make sure nothing is touching the underside of the board (like the USB plug/port/connector) that could cause a short somewhere...

I also agree that photos of your board - top and bottom, and perhaps photos of it mounted on the Arduino would be helpful...

I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.


Another long shot:

Make sure nothing's touching the ICSP connector.


PC saying that windows does not recognize the USB device

This is the clue, it is not even getting so far as to what is happening on the processor, your bridge is stopping the USB / serial bridge form being recognised on the PC side. This will rule out shorting or mangling of any signals on the ATMEGA side so you must be doing something to the bridge. The other thing to check is that you have not shorted out, or some how put signals into the 3V3 supply. That comes directly from this chip and is another way of making it not function as far as the PC is concerned.

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