nRF52810 board will not start on its own. It needs the RTT Viewer to be connected, then it will start and run.

RE: nRF52810 board will not start on its own. It needs the RTT Viewer to be connected, then it will start and run.

epolicar — Sun, 08 Jun 2025 17:44:36 GMT

After digging deeper into the code, not just my code but NCS (so deep that led to gpio_nrfx.c), I found that DCDC is not disabled! I relied on the datasheet saying the default is LDO, and menuconfig has SOC_DCDC_NRF52X = n. But the devicetree's default is DCDC. In the dts file,

&reg {

regulator-initial-mode = <NRF5X_REG_MODE_DCDC>;

I override it in the overlay file,

&reg {

regulator-initial-mode = <NRF5X_REG_MODE_LDO>;

My board starts on its own.

Since my board is wired to run on LDO regulator, having the DCDC enabled caused the check for DCDC in gpio_nrfx.c to reset the board. main() is never reached so it looked like the board is not starting; it was actually resetting continuously. Somehow, connecting the RTT Viewer "corrected" the issue making my board run normally.

RE: nRF52810 board will not start on its own. It needs the RTT Viewer to be connected, then it will start and run.

epolicar — Tue, 03 Jun 2025 17:53:28 GMT

[quote userid="91187" url="~/f/nordic-q-a/120786/nrf52810-board-will-not-start-on-its-own-it-needs-the-rtt-viewer-to-be-connected-then-it-will-start-and-run/532857"]Looks like the VDD on pin 32 has the wrong component value, should be 4.7uF but you have 100nF.[/quote]

I added a 4.7uF. Same result.

Here is additional observation:

I changed setup to power my board separate from the debugger. When the RTT viewer gets 'logically' connected (clicking on Connect on the dropdown of J-Link RTT Viewer app), my board starts and run OK. If I 'logically' disconnect the RTT Viewer, my board stops running. However, if on the other hand I physically disconnect the debugger, my board continuously run.

Your thoughts? What is it about the debugger that makes this behavior in my board?

I appreciate your answer.

RE: nRF52810 board will not start on its own. It needs the RTT Viewer to be connected, then it will start and run.

epolicar — Fri, 09 May 2025 23:03:43 GMT

nRF Connect SDK for VS Code v2.9.0/2.9.1 and Zephyr v3.7.99

RE: nRF52810 board will not start on its own. It needs the RTT Viewer to be connected, then it will start and run.

JONATHAN LL — Mon, 28 Apr 2025 12:53:21 GMT

Can you also share what SDK version you are using?

RE: nRF52810 board will not start on its own. It needs the RTT Viewer to be connected, then it will start and run.

epolicar — Mon, 28 Apr 2025 11:51:28 GMT

Yes DCDC is disabled.

I will let you know what happens after I changed the cap to 4.7uF.

RE: nRF52810 board will not start on its own. It needs the RTT Viewer to be connected, then it will start and run.

JONATHAN LL — Mon, 28 Apr 2025 06:58:35 GMT

What version of the SDK are you using ?

When using RTT Viewer the device is forced in debug mode, so that is why. Debug mode forces a few settings power and clock. In your other projects you dont have the configs correctly set up so that is why only debug mode works.

See: https://devzone.nordicsemi.com/f/nordic-q-a/98203/nrf52832-can-not-run-without-debugger/418083
https://devzone.nordicsemi.com/f/nordic-q-a/112027/segger-rtt-viewer-connection-latches-device-to-high-power-if-not-disconnected/488497

Are you disabling the DCDC?

Regards,
Jonathan

RE: nRF52810 board will not start on its own. It needs the RTT Viewer to be connected, then it will start and run.

epolicar — Sat, 26 Apr 2025 00:58:24 GMT

Even the Blinky example will not start on its own unless RTT viewe is connected.

I would appreciate a reply.

Regards,

RE: nRF52810 board will not start on its own. It needs the RTT Viewer to be connected, then it will start and run.

epolicar — Fri, 25 Apr 2025 05:01:48 GMT

[quote userid="91187" url="~/f/nordic-q-a/120786/nrf52810-board-will-not-start-on-its-own-it-needs-the-rtt-viewer-to-be-connected-then-it-will-start-and-run/532857"]See if the external crystals are mounted the correct way. the LFXO (32kHz) should work, but the HFXO(32MHz) can be mounted wrong if rotated 90 degrees. So double check that. [/quote]

HFXO is mounted correctly.

[quote userid="91187" url="~/f/nordic-q-a/120786/nrf52810-board-will-not-start-on-its-own-it-needs-the-rtt-viewer-to-be-connected-then-it-will-start-and-run/532857"]

CONFIG_CLOCK_CONTROL_NRF_K32RC_SYNTH=y

CONFIG_CLOCK_CONTROL_NRF_K32RC_XTAL=n

[/quote]

These settings did not work.

RE: nRF52810 board will not start on its own. It needs the RTT Viewer to be connected, then it will start and run.

JONATHAN LL — Thu, 24 Apr 2025 14:07:41 GMT

Looks like the VDD on pin 32 has the wrong component value, should be 4.7uF but you have 100nF.

When a debugger attaches to the device, it forces power and clock domains to remain on, which can mask power-related issues in your application. That is what I am suspecting happens in your case.

Also you do NOT have DCDC on this design so you need to make sure that the device only runs software that has DCDC disabled.

See if the external crystals are mounted the correct way. the LFXO (32kHz) should work, but the HFXO(32MHz) can be mounted wrong if rotated 90 degrees. So double check that.

Maybe try to use the synth clock:

Belive these should do.

CONFIG_CLOCK_CONTROL_NRF_K32RC_SYNTH=y

CONFIG_CLOCK_CONTROL_NRF_K32RC_XTAL=n

Regards,
Jonathan

RE: nRF52810 board will not start on its own. It needs the RTT Viewer to be connected, then it will start and run.

epolicar — Thu, 24 Apr 2025 13:11:34 GMT

I cannot get a waveform from both LFXO and HFXO since the start. Could this be why, eventhough, I enabled internal RC?

RE: nRF52810 board will not start on its own. It needs the RTT Viewer to be connected, then it will start and run.

epolicar — Thu, 24 Apr 2025 13:08:40 GMT

Her is the schematic pdf:

devzone.nordicsemi.com/.../beacon.pdf

RE: nRF52810 board will not start on its own. It needs the RTT Viewer to be connected, then it will start and run.

JONATHAN LL — Thu, 24 Apr 2025 09:28:56 GMT

Can you share a PDF file of the schematic, the resolution here was not great and a bit difficult to read.

If you are able to flash and debug as well as rund at least some code on the device then I suspect the main issue is some configuration in SW.

Might be related to the use of the LFXO and if it is used or not but can also be a HW issue. Is it mounted correctly ?

Regards,
Jonathan

RE: nRF52810 board will not start on its own. It needs the RTT Viewer to be connected, then it will start and run.

epolicar — Thu, 24 Apr 2025 06:07:42 GMT

Yes, I did.

I made a bare metal code that blinks LED. This code starts up on itw own upon power up. Could the problem be in Zephyr start up code and configuration?

RE: nRF52810 board will not start on its own. It needs the RTT Viewer to be connected, then it will start and run.

JONATHAN LL — Wed, 23 Apr 2025 06:17:03 GMT

How does the board get power?

Can you share schematics?

[quote user="epolicar"]All my SW does not work.[/quote]

Have you tested som basic samples ?

Regards,
Jonathan

RE: nRF52810 board will not start on its own. It needs the RTT Viewer to be connected, then it will start and run.

epolicar — Tue, 22 Apr 2025 09:20:04 GMT

Hi Jonathan, I would like to follow up on this

RE: nRF52810 board will not start on its own. It needs the RTT Viewer to be connected, then it will start and run.

epolicar — Mon, 21 Apr 2025 12:54:39 GMT

Also, RTT viewer is not in debug mode.

RE: nRF52810 board will not start on its own. It needs the RTT Viewer to be connected, then it will start and run.

epolicar — Mon, 21 Apr 2025 11:46:24 GMT

All my SW does not work.

RE: nRF52810 board will not start on its own. It needs the RTT Viewer to be connected, then it will start and run.

JONATHAN LL — Fri, 18 Apr 2025 01:01:32 GMT

This issue is common to see when the 32kHz crystal is missing, the RTT viewer start ste device in a debug mode so then it simulates it internally.

Doas all SW not work or just yours?

Have you tested something else?

Regards,
Jonathan