nRF52840-DK

[Josh_1]

Hi,

Board (nRF52840-DK) flashing by mistake with nRF52840 Dongle software and then "dead" !!! maybe the boot erased.

While trying to connect with SEGGER J-Link I got "Cannot connect to target" ,Is there any hardware procedure 

'nrfjprog --recover' and/or '--eraseall'  were done and not help! 

Any other factory reset procedure or Hardware procedure to get out of from this case? 

Thanks

[Øyvind]

Hello,

Does your board list as a JLINK drive in My Computer? Are you able to find the board in Device Manager (if using Windows)? It should list under Ports as JLink CDC UART Port

How did you flash the device? In SES or via command line?

Kind regards,
Øyvind

[Josh_1]

Hi,

Sorry for my delay response.

I flashed with SES.

As a principle , In case of device which is in the field and need to be download firmware over the air and something damaged while downloading (for example ,different firmware, boot damaged and etc ) ,in this case there is need for FACTORY DEFAULT,I wonder if the FACTORY DEFAULT procedure to the SoC nRF52840 will be like describe below, 

[Einar Thorsrud]

Hi,

It should not be possible to mess up the onboard debugger by programming from SES. If the onboard debugger is OK, then it should always be possible to recover using "nrfjprog.exe --recover". This will return the nRF52840 chip to the factory default state (empty flash, including empty UICR).

If on the other hand, the problem is that something happened to the onboard debugger, then you can try to reprogram it by pressing and holding the reset button while power cycling the board. Then you will see it appear as a mass storage device called "BOOTLOADER", and LED5 will be slowly blinking. In this state you can upgrade the IF firmware by dragging and dropping it onto the device, waiting a bit and power-cycling the board. You can download the "Interface MCU firmware" from here (it works on all nRF52xxx DK variants).