LTE Serial Monitor UART Sleeping maybe due to config

[Aziz]

Hello,

I noticed with the LTE Serial Monitor example code on a custom board with nrf9160 (and also the nrf91dk), the UART interface work initially but sometimes hangs. It looks like the device gets into a sleep mode and can't wake up when I type serial commands after a period of time. I did not configure/activate UART flow control pins (RTS/CTS). 

How do you prevent this situation from happening? Is UART flow control required to prevent this situation from occurring? Or something else?

Thanks.

[Hakon]

Hello,

what NCS tag are you on? What modem firmware are you using?

[Hakon]

Also, do you have CONFIG_SLM_EXTERNAL_XTAL enabled?

[Jun Qing ZOU]

Please config CONFIG_SLM_LOG_LEVEL_DBG=y then use RTT to debug UART interface issue

[Aziz]

I think I tracked this down to an issue with LTE Link Monitor. I hooked up toggle LEDs for RX/TX and notice that they don't turn on after sometime while using LTE Link Monitor (so no data is send to the nrf chip). However, if I use a different serial terminal like Teraterm, after I wait a few minutes, I am still able to send data and see the LEDs toggle. I notice with NRF Connect, I have to refresh the page and close/reopen the uart port. Why does this happen?

I am using LTE Link Monitor v1.1.10 and nrf Connect SDK Release - 1.5.1.

[JONATHAN LL]

Hi,

Could you provide more info on your setup?

Windows\Mac\Linux ?

Are you using a USB hub or connecting directly in to the computer?


Could you try to revert to a previous version of LTE Link monitor? to see if the problem still exists there?


Regards,
Jonathan