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Topic: Custom SAM3X8E board "Unknown USB Device (Device Descriptor Request Failed)" (Read 303 times) previous topic - next topic



As many other people have done since the Arduino due came out, I have designed my own PCB based on the Arduino Due design. 

I have run into a bit of an issue where I cant use seem to get a pc to recognise the board when it is plugged in, I get the "Unknown USB Device (Device Descriptor Request Failed)" Error shortly after its plugged in but sometimes it can take a minute or two for windows to present this. Sometimes windows throws up the "Unknown USB Device (Port Reset Failed)" instead.

The board uses a surface mount USB C type connector which is in place of the native USB port on the DUE and I have not connected any of the OTG functions as I don't need this board to act as a host. Instead of using the UOTGID pin, it is left floating and pulldown resistors are used on the USB C connector as standard.  

I have also gone through and checked all of the connections on the board which are correct and then verified all the voltages according to the SAM3X8E Checklist and datasheet, which all seem to be in order, the crystal seems to have power and when I comparing the voltages on the Arduino due to this custom board, they are all the same. 

I have used a USB to serial adapter (Like this one) connected to the TX0 and RX0 pins of the real Arduino due to program it via Arduino online IDE, just to prove it is possible and then tried soldering some wires to the TX and RX pins of the custom board to do the same but the IDE just fails when it can't find any device on the COM port. I have an updated version of my custom board on the way with TX, RX, 3.3v and GND headers on to allow me to test this properly. 

Other than that I can't think of what else could be the problem. When the new boards with the headers arrive I will try to program the chip via TX/RX, and if it works I assume the problem is on the USB Data lines somewhere, although I have used impedance controlled traces for the USB Data lines. If I cannot program the chip via the TX/RX then can assume that the problem is with the board layout or components. 

I have attached an image of the schematic and board layout, it would be great if anyone could give me some help with this  :).

Thanks in advanced.,


I would recomend to read chapter 20 of Sam3x datasheet plus this Application Note:

Your custom board should behave as a USB Device vis a vis the USB Host (your PC or an Arduino DUE connected thru the Native USB port).

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