NRF54L15 Zephyr Blinky Sample did not start at Power on

[Gerd Breidenstein]

Hi

The Blinky Programm only starts when I give the reset Go command via jlink commander.

At Power cycle nothing happens.

If i give the SOC an external Pin reset the running programm stops but never starts

[Edvin]

Hello,

Sorry for the late reply (had to stay at home with the kids after being assigned your ticket). 

So it only runs if you start it manually using JLink commander, right?

What HW are you running on? I suspect it is not an nRF54L15 DK, but a custom board, or a 3rd party kit?

If it only runs when started by JLink, I suspect it is a clock "issue". That is usually the case when something only runs in a debug session, but not when run normally. The cause is usually that the LFCLOCK (32kHz) is not properly configured. Since the LFCLK XTALis optional, some 3rd party or custom boards don't have them, but most of the samples assume that it is present. 

If that is the case, try adding this line to your prj.conf:

CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y

And see if it makes any difference. This will tell the application to use the internal RC oscillator instead of an external XTAL for the 32kHz clock source. Please let me know if it works or not.

Best regards,

Edvin

[Gerd Breidenstein]

Hi Edvin
It did not work with "CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y" 

but ... when I added 

CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=n

CONFIG_CLOCK_CONTROL_NRF=n

to my prj.conf  a CMake warning came up "No SOURCES given to Zephyr library: drivers__clock_control"

and the programm started as normal

Does this help you to find the reason od my starting problem? 

[Edvin]

That is strange. Can you please zip and upload the application where this happened, and I can have a look. I don't know what happens if you don't provide any clock source. Perhaps it defaults to the RC Oscillator. 

What HW are you running this on? Custom hardware, or an nRF54L15 DK? 

[Gerd Breidenstein]

Hi Edvin

Don't know how ti attach zip
I used a Ublox NORA-B206-00B on a prototype PCB

[Edvin]

Gerd Breidenstein said:

Don't know how ti attach zip

just drag and drop it into where you are typing. Alternatively: Insert -> image/video/file -> then click the upload button:

It is not clear to me whether they have put a 32kHz Crystal (LFXTAL) in that module. I can't seem to find any datasheets. If you are not sure, reach out to the distributer that you used to purchase the module, and ask if you can get the datasheet. 

Does the way that you supply power change when you are running the debug session and when you are trying it without the debugger attached?

Best regards,

Edvin