How to enable JLINK RTT modem trace for the at_client sample in NCS v3.2.3?

[RongLinQin]

Hi nordic support:

      Our product uses the nRF9151 and  prepare for GCF certification testing, which need to capturing LTE mode trace log.

       We first intend to try running the NCS v3.2.3's at_client sample program on the nRF9160DK,  and capture the trace logs via J-Link RTT. Could you please advise on how to modify the at_client sample's config to capture trace logs in Cellular Monitor? 

       Thanks!

BRs

Qin, Rong-Lin

      

[Hung Bui]

Hi Ronglin, 
Have you followed the guide here: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/libraries/modem/nrf_modem_lib/nrf_modem_lib_trace.html#modem_tracing_with_rtt

Or you can use the snippet as described here: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/app_dev/device_guides/nrf91/nrf91_snippet.html#nrf91-modem-trace-rtt-snippet

Basically it's these configurations: 

CONFIG_NRF_MODEM_LIB_TRACE=y

# Modem trace RTT backend
CONFIG_NRF_MODEM_LIB_TRACE_BACKEND_RTT=y

# RTT configuration
CONFIG_USE_SEGGER_RTT=y

[RongLinQin]

Hi HungBui:

       Thanks for your help!

       I tried added these RTT trace configurations in  at_client's prj.conf as picture "prj_conf.png".  Then build the project and download  the "merged.hex" to nRF9160DK.  Then use JLinkRTTLogger command to capture modem trace rtt log as picture "rtt_log.png". When  I start Cellular Monitor and Refresh dashboard, some AT commands can be seen being sent in the Serial Terminal, but no data is captured by JLinkRTTLogger. Could you help us to check it ?

BRs

Qin, Rong-Lin

[Benjamin]

Hi,
The Cellular Monitor application does not support RTT directly. You will first need to capture the trace as a .log file using the J-Link RTT logger software and then convert it using Cellular Monitor as described here.

Regards,
Benjamin

[RongLinQin]

Hi Benjamin:

     Thanks for your help!

     After added the -RTTChannel parameter to the JlinkRTTLogger command, LTE RTT trace log could be captured.  Following is the command parameters we used:

     JlinkRTTLogger -Device nRF9160_xxAA -If SWD -Speed 4000 -RTTChannel 1 e:\ch1.bin

     However, the current speed of capturing  jlink RTT is slow,  the maximum speed of our board is about 70 KB/s. Capturing logs for a single LTE network attachment operation takes more than ten minutes. Sometimes the captured logs cannot be decoded by wireshark, and we are not sure if this is due to incomplete log capture caused by the slow speed. Could you give us some guidance on optimizing the JLink RTT capture log speed?

      thanks.     

BRs

Qin, Rong-Lin

[Øyvind]

Hello, I have been asked to follow-up on your ticket while Benjamin is out of office. 

Could you please share the logs that you are able to capture? This way we can see if it is sufficient or not. 

Thanks. 

Kind regards,
Øyvind

[RongLinQin]

Hi Øyvind:

    Thanks for your help. 

    We tried modifying the following two configuration options. After increasing TRACE_BACKEND_RTT_BUF_SIZE and TRACE_STACK_SIZE, we can capture logs normally now. Could you help check what values should be set for these two configuration and the MODEM TRACE LEVEL for  GCF certification test? 

CONFIG_NRF_MODEM_LIB_TRACE_BACKEND_RTT_BUF_SIZE=16384
CONFIG_NRF_MODEM_LIB_TRACE_STACK_SIZE=8192

    Thanks!

BRs

Qin, Rong-Lin

[Øyvind]

Hello, I am not aware of any levels needed to be set for GCF Certification tests, but the numbers seem sufficient. If you can collect modem traces correctly, this should correct.

Kind regards, 
Øyvind