How to gracefully shut down nRF9160 modem

RE: How to gracefully shut down nRF9160 modem

Dominic — Wed, 23 Oct 2024 22:12:07 GMT

Thank you. I was able to solve the issue on modem version 1.3.6 by introducing a short delay between calling CFUN=0 and powering off the device.

RE: How to gracefully shut down nRF9160 modem

dejans — Thu, 10 Oct 2024 12:44:17 GMT

Hi,

When send() has returned that data has not been sent yet, it has only been queued to be sent. Sending happens usually shortly afterwards.
Switching to CFUN=0 and powering off prevents the last message from going out. There is a proper way for data to be sent in modem firmware version 2.0.x but not in 1.3.x. Therefore, you would need to implement something at protocol level (e.g. waits for ack to the last message) or you would need to wait couple of seconds after the very last send() operation before switching to CFUN=0 and turning off the power. However, if by "modem does not send a data session ended event" you think about something LTE related, then we would need a modem trace for further investigation.

Best regards,
Dejan

RE: How to gracefully shut down nRF9160 modem

Dominic — Wed, 09 Oct 2024 17:35:25 GMT

Unfortunately I won't be able to get modem logs until next week. In the meantime, can you confirm the presence of this 'ready' flag for cutting power to the nRF9160 that the Nordic FAE mentioned?

RE: How to gracefully shut down nRF9160 modem

dejans — Tue, 08 Oct 2024 14:12:46 GMT

Hi,

Could you provide logs in those two different scenarios - AT+CFUN=4, and AT+CFUN=0 and npm1300 in ship mode?

Best regards,
Dejan