Greetings all -
We have an nrf51-dongle for development and testing purposes, and are unable to connect to the device over USB with any of the Segger or Nordic tools. I've extensively searched the forums, and solutions offered for other "not connecting" issues have not worked. The way our dongle is behaving appears to be unique to the other posts.
After the dongle sits unpowered for a long time (say hours, or overnight), if then attached to a Windows system, the USB device and COM port are recognized upon connection (and both standard and bootloader mode have been found to operate this way). However, if the dongle is removed, then reattached in a reasonably short time (say, 10 minutes or less), the device is only recognized as an "Unknown Device" under USB devices. Baffling, to say the least.
Neither connection scenario permits successful communication with the device. When the USB device is correctly recognized as noted above, tools such as JLinkCommander and nRFGo Studio see the USB device and COM port, but are unable communicate with it. Attempts such as "Recover" in nRFGo Studio result in "invalid operation, and "nrfjprog.exe --recover" via the command line fails with "JLinkARM.dll reported an error". The recovery sequence listed bellow via JLinkCommander was found elsewhere in the forums for an alternate recovery method, but each command results with "WARNING: Out of sync, resynchronizing".
r
w4 4001e504 2
w4 4001e50c 1
w4 4001e514 1
qc
When the USB device is properly recognized by Windows, a mass storage device is correctly mapped, but on any attempt with it (copying a firmware file, creating a folder, etc), Windows gives an error "Could not find this item. It is no longer located in Computer".
In the secondary (and most easily reproducible) scenario where the device is reattached to the PC and recognized only as an "Unknown Device", none of the tools "see" the dongle (as would be expected with improper enumeration).
We have not physically modified the board in any way. We are using the latest Nordic and Segger tools/drivers. On receipt, we had attempted to update the JLink firmware, and the device appeared to accept it as documented. At this point, however, I suppose it's difficult to say with any certainty what presides on the device. The dongle successfully connected only a handful of times before entering its current state.
Any assistance would be most appreciated, and I hope I've not overlooked something obvious. After too many hours on it, it sure seems bricked to me, but I've read elsewhere that this would be a very unusual situation.
Regards,
Rick
EDIT 10/15/15
Per RK's suggestion, I have confirmed that rebooting the PC causes the "detected as an Unknown Device" scenario to occur more readily. However, this issue is not related to a specific PC or operating system, as I've confirmed this behavior across multiple Windows 7 and XP machines, as well as Linux. In other words, still sitting on an otherwise inoperable dongle.
