Maximum AT Command Wait

RE: Maximum AT Command Wait

leox — Tue, 08 Jun 2021 07:59:44 GMT

Hi Thomas,

AT socket doesn't support Non-blocking, the poll() is ok with BLOCKING sockets.

poll() examples can be found in nrf\applications\serial_lte_modem\

RE: Maximum AT Command Wait

Thomas — Sat, 05 Jun 2021 06:26:47 GMT

Hi Markus,

It throws error number 95 (not supported). You can repeat it by just setting the don’t wait flag in the send function on an AT socket.

Kind regards,

Thomas

RE: Maximum AT Command Wait

Albrecht Markus Schellenberger — Fri, 04 Jun 2021 12:33:28 GMT

Hello Thomas,

what kind of error does the send function throw? Do you have a test application or something, which you could share?

Regards,

Markus

RE: Maximum AT Command Wait

Thomas — Fri, 04 Jun 2021 05:48:38 GMT

I think the issue is with the modem library. I've been trying to create error conditions and if you close an AT socket, or shutdown the modem library while a thread is either trying to receive or send on the socket, that thread is stuck forever.

This could be fixed by using non blocking sockets and polling for events instead, but when you try and set the send function as non blocking on an AT socket, it returns an error. Any ideas? (Currently using v1.5.1 of the SDK)

RE: Maximum AT Command Wait

Thomas — Fri, 04 Jun 2021 03:54:47 GMT

Hi Markus,

I can't do that, it is happening to devices in the field that are battling to register, but only happening rarely.

RE: Maximum AT Command Wait

Albrecht Markus Schellenberger — Thu, 03 Jun 2021 12:39:22 GMT

Thanks for the feedback, Thomas!

That sounds strange, indeed! I wouldn’t have expected such response times for those AT commands.

Could you please provide me with a modem trace that captures the situation? Thanks!

Regards,

Markus

RE: Maximum AT Command Wait

Thomas — Thu, 03 Jun 2021 08:30:30 GMT

Hi Markus,

The problematic AT commands appear the AT%XVBAT and AT%XTEMP. We are sending these commands approximately every 60ms. When in coverage this is fine, but when on on the edge of coverage (unit is in a garage), the AT socket seems to stop responding.

What is strange is that this seems to occur exactly 1 minute and 40 seconds after the sending the AT+CFUN=1 command?

RE: Maximum AT Command Wait

Albrecht Markus Schellenberger — Thu, 03 Jun 2021 07:44:53 GMT

Hello Thomas,

which AT commands are you using that take time? Most AT commands should give a response quite quickly, while commands like searching for networks might take some time.

Regards,

Markus