Ublox n211 reboot cause application watchdog problem

Hi,

I’m using the NB-IoT shield with the Sara N211 and are getting a REBOOT_CAUSE_APPLICATION_WATCHDOG every 2 hours and 4 to 5 minutes. I’m sending messages over UDP to Vodafone network and this works fine for about 2 hours and then it reboots. In the manual there is no information on what exactly this application watchdog is. Does anyone have more information about the application watchdog and how to prevent it from triggering?

Best Regards,
Frans.

Hi @FransKanters,

How do you power the board?
It is not really clear why this happens, I had this reboot cause with a board, I could relate the to the power source.
If you don’t have a lipo attached to the board, can you check if it also happens when there is an lipo attached?

Best regards,
Jan

Hi Jan,

The sodaq NB-IoT shield is powered by a 3V3 regulator from another board, which is powered by a 5V/1A USB PSU. I also tried a lab PSU at 3V3, with the same results. Never tried 3.7V though.
The strange thing is that everything works fine for 2 hours and 4 or sometimes 5 minutes. If it was a power problem I would expect more random events, not exactly at constant intervals.
Did you notice the problem at the same intervals?

Best regards, Frans.

Hi @FransKanters,

I will see if I can replicate the issue.
Do you have a default sample interval?

Best regards,
Jan

Hi Jan,

I send an UDP packet every 30 seconds. The packet is 28 bytes long. I receive an acknowledge package after every sent packet from the server with a length of 7 bytes. All packets are CRC checked.

Best regards,
Frans.

Dear @FransKanters,

I haven’t been able to replicate the 2h5m reset.

What is the firmware version of the N211 you use?
Can you maybe send me an email with the sketch you use?

Best regards,
Jan

Hi Jan,

Thank you for your effort to help me. I’m using U06_57_A09.06. The arduino shield is connected to a proprietary board over UART to an AT xmega. I’m using the old version without host processor of the Sodaq board. I’m not allowed to share the code though. After the holidays I will try to see if other firmware helps. I do have an old board lying around (non Sodaq) which seems to connect for longer periods with the same host and code…

Best regards, Frans.