DFU stops advertising in Run Mode

[blungreen]

Hello,

i have a strange behaviour on a board with nRF52. The board is flashed with SD 4.0.2 and bootloader.

On Keil If i load the bootloader with JLink, it runs and i can connect, but if i reset the board i see three adv packets with the sniffer but then it stops.

If i go into debug it works. It looks like it's working only if i connect jlink and do some work with it (load, debug). I have other boards and they work fine.

We thought it could be something hardware so we started to play with reset pin and we found that after a bunch of reset toggle, the reset pin stops working and the device won't reset anymore. Need to power cycle.

With the other boards, the reset pin works fine.

I have read some post about nrf51 entering debug mode. Does this still apply on nrf52? Do you think there is correlation between the behaviours?

[Hung Bui]

Hi,

How do you reset the board ? It's a power reset or reset from Jlink ? Right after programming on nRF52 it also enters debug mode so the reset pin doesn't work.

Have you modified the bootloader example ? Could you try with a fresh SDK ?

You can try to printout UART/RTT log to see if the bootloader crashed at something ?

[blungreen]

Hello, reset pin is pulled up and decoupled and it is connected to a supervisor. Jlink connects to reset pin. I have tried with bootloader from fresh SDK, same thing. I have measured abnormal current consumption, about 19mA, while working board has 4mA.

[Hung Bui]

19mA is pretty strange, have you tried some very simple firmware, such as blinky and check if the current drop ? I suspect the chip is damaged. Would there is any chance it has been connected to unsupported supply voltage ?

[blungreen]

It is damaged for sure, there are couple of sparee io i can't drive. Voltage always around 0.3V no matter if driven high or low. Supply voltage comes from a linear regulator 5V -> 3v3 which feeds a 3rd party module configured for DCDC supply.

[Hung Bui]

I would suggest to replace the chip. If you see the issue again on that board or other boards, please let us know.