EMU_GetFirmwareString: Insufficient data read when trying to read the string length.

[TTk]

Hello 

I was using the NRF52840 dev kit as J-link to develop a custom board. at first was working, i uploaded a blink code to it then i modified the libry from gpio.h to boards.h and ran and example code but after the uploaded one led stays constantly on and the J-Link dosen't connect again. i'm using segger embedded studio.

this is the error

Connecting ?J-Link? using ?USB?
Loaded /Applications/SEGGER Embedded Studio for ARM 6.40/bin/libjlinkarm.dylib
EMU_GetFirmwareString: Insufficient data read when trying to read the string length.
 Insufficient data read when trying to read the string length.
Cannot connect to J-Link

[Jared]

Hi,

Can you tell me exactly what changes you applied to gpio.h and boards.h?

Does the board show up as Jlink in file explorer when you connect it to the computer?

regards

Jared 

[TTk]

yes the board shows up as jlink in finder (I'm using mac OS) 

if I don't connect the custom the nRF52840 dev kit connects and downloads the code effectively.

i change LED_1 to 19 and BSP_LED_0 to 19 in pca10056.h. and after I uploaded it, the custom board doesn't connect anymore

[Jared]

Hi,.

TTk said:

i change LED_1 to 19 and BSP_LED_0 to 19 in pca10056.h. and after I uploaded it, the custom board doesn't connect anymore

I tried to apply these changes to the PCA10056.h file and then re flashed the blinky example, but I was still able to connect to the DK. Can you share your modified pca10056.h file?  Above you mentioned that you were using a DK but now you mentioned a custom board? Which one are you using?

regards
Jared 

[TTk]

this is the design of the custom board

[Jared]

Hi,

Could you also share your pca10056.h that you modified?

regards

Jared

[TTk]

i think the custom board is bad, i used another custom board, and it worked

[Jared]

Hi,

Ok, that's great. Did you have any further questions regarding this problem?

regards

Jared

[TTk]

please I really need help understanding the nrf52840 and segger embedded studio. its my first time working with it. if possible can I have a session with you?