nrf52840 doesn't execute code

[testter2]

I'm working with nrf52840

i was working on one of examples of BLE and after editing the code 'then burned it on the kit

the code is burnt on the kit , but isn't executed . and i tried many examples but it appears that no code is ever executed.

Thanks

[Turbo J]

No code execution at all usually means you forgot to flash the corresponding softdevice.

If the program counter seems stuck in a high flash memory address, you have flashed a bootloader. This requires extra steps -generating and flashing the bootloader settings page - when trying to put a new program into the chip via debugger.

[testter2]

any steps to solve this problem .

i tried to use firmware here

https://www.nordicsemi.com/Software-and-Tools/Development-Kits/nRF52840-DK/Download#infotabs

but also doesn't solve the problem