BLE DFU nRF5280,nRF5340

RE: BLE DFU nRF5280,nRF5340

Macherla Swetha — Thu, 18 Jun 2026 08:46:09 GMT

ok thankyou , thanks a lot for early response

RE: BLE DFU nRF5280,nRF5340

Vidar Berg — Thu, 18 Jun 2026 07:39:17 GMT

Our SDK examples will typically spend >99% of the time in sleep (from the idle thread), and it is difficult to comment on why you are seeing the high cpu usage in your case without any details about your code. I would recommend you go through our devacademy course here: https://academy.nordicsemi.com/courses/nrf-connect-sdk-fundamentals/lessons/lesson-7-multithreaded-applications/topic/scheduler/.

RE: BLE DFU nRF5280,nRF5340

Macherla Swetha — Thu, 18 Jun 2026 07:18:22 GMT

yes it works with by removing while();, ... when we look into real projects if main loop having more to excute alomst main only uses 98% of cpu cycles.. what we can do?

RE: BLE DFU nRF5280,nRF5340

Vidar Berg — Thu, 18 Jun 2026 05:49:24 GMT

I see the empty while loop you have in main() now. This will prevent other lower priority threads from running and it explains why the device is not responding to the mcumgr commands. Solution is to simply remove your while() loop and let the program exit the main thread.

RE: BLE DFU nRF5280,nRF5340

Macherla Swetha — Thu, 18 Jun 2026 04:23:06 GMT

I think it is beacause of main thread using more CPU cycles...when i put delay to cpu idle , dfu working fine...

1. is there any solution / implementation methods for this instead of delay..?(except threads)

RE: BLE DFU nRF5280,nRF5340

Macherla Swetha — Wed, 17 Jun 2026 11:55:36 GMT

RE: BLE DFU nRF5280,nRF5340

Vidar Berg — Wed, 17 Jun 2026 11:51:19 GMT

I meant to ask if you could provide debug logs from your nRF52 devices which you are trying to perform the dfu on.

RE: BLE DFU nRF5280,nRF5340

Macherla Swetha — Wed, 17 Jun 2026 11:48:33 GMT

same thing happens with "config_log" also

RE: BLE DFU nRF5280,nRF5340

Vidar Berg — Wed, 17 Jun 2026 11:41:27 GMT

Hello,

The log is only showing that the connection is terminated after what looks to be the "image list" command, but it does not give any indication of why. I think it would be more helpful here if you could get debug logs (CONFIG_LOG=y) from your DFU target.

Best regards,

Vidar