NRF51 DK - Not recognized/not Blinking/Error on drag and drop

[teodf]

Hi,

Currently I work on an NRF51 DK, by mistake I replace my bootloader by and .hex or .bin file with a drag and drop.

The LED 5 don't blinking and my computer don't detect the device but I have a voltage on VDD. When I want to do --eraseall, the computer says "There is no debugger connected to the pc".

Someone have an idea to fix this ?

Regards,

Téo DHIEN-FANE 

[Einar Thorsrud]

Hi.

You can re-flash the onboard debugger by holding the reset button by power cycling and then dragging the interface MCU firmware you download from here onto the removable drive (the same firmware is used on both the nRF51 and nRF52 DKs) . Then after some time power cycle again, and the debugger should work.

[teodf]

It's impossible to dragging the file because the device don't appear in File Explorer 

[Einar Thorsrud]

Did you try to hold the reset button while power-cycling the board? Then you should see the board enumerating as BOOTLOADER and LED 5 should blink slowly (frequency of about 1 Hz). Does that not happen?

[teodf]

That not happen, I can't see BOOTLOADER and no LED blinking

[Einar Thorsrud]

I see, that should not have been the case. Is the power switch on (stupid question I know, but just to be sure)? Are any LEDs lit at all, or does the DK seem dead This should not happen, so I wonder if the DK was functional at an earlier time? What happened in the mean time? Did you do any modifications that could have caused an HW issue? A last thing worth testing ia a different USB cable. The caple might be damaged, or perhaps you have a USB-cable for charging only (with no wires for data).

[teodf]

Yes the card is well supplied and switched on, I tested with another cable and it is the same and I have no LED on.
I have another DK I tried the previous manipulation and it works fine.
Before having the problem I did a bad manipulation I managed to display Bootloader in the file explorer and I drag and drop a .hex file and I think that's what put it in a weird state.
I did not connect any equipment besides only the usb cable.

It's possible to do a hard factory reset ?

[Einar Thorsrud]

Hi,

If the firmware on the interface MCU is corrupted and it is no longer possible to put it in DFU mode, then I do not see any other way to recover than to hook it up to an external debugger. There is no header for that on the DK though so it might be a bit difficult. Perhaps it would be best to just scrap the board. It is interesting though, I do not recall ever seeing such an issue before, and it is a bit odd that you were able to break it by copying a .hex onto it.