problem about AT%XCBAND=?

RE: problem about AT%XCBAND=?

Håkon Alseth — Tue, 19 Nov 2024 11:07:32 GMT

Hi William,

If we look at the documentation for XSYSTEMMODE:

https://docs.nordicsemi.com/bundle/ref_at_commands/page/REF/at_commands/mob_termination_ctrl_status/xsystemmode_set.html

You are enabling both NB + LTE-M modes, then enabling the modem. It will start up with LTE-M and then switch over to NB-IoT. Could this be the reason why you're seeing this behavior?

Try setting "at+cereg=5" and checking the return (at+cereg?) for each time you poll the %XCBAND to verify which mode is used.

Kind regards,

Håkon

RE: problem about AT%XCBAND=?

William.wei — Mon, 18 Nov 2024 07:06:02 GMT

yes Hakon,

the same mfm1.3.6 as you.

You are reproducing my question, you can set AT%XSYSTEMMODE=1,1,0,0, and please try again.

you can see that %XCBAND: (2,4,12,13,17) appears at about 15 seconds.

Regards,

William.

RE: problem about AT%XCBAND=?

Håkon Alseth — Fri, 15 Nov 2024 13:05:00 GMT

Hi William,

My apologies for misunderstanding the scenario.

I tried to recreate this locally, but was not able to do so:

[2024-11-15 13:59:38] *** Using Zephyr OS v3.7.99-adcffa835a8e ***
[2024-11-15 13:59:38] The AT host sample started
[2024-11-15 13:59:38] Ready
[2024-11-15 13:59:43] AT%XFACTORYRESET=1
[2024-11-15 13:59:44] OK
[2024-11-15 13:59:50] AT%XBANDLOCK=1,"10001100000001010"
[2024-11-15 13:59:50] OK
[2024-11-15 13:59:54] AT%XBANDLOCK=2,"10001100000001010"
[2024-11-15 13:59:54] OK
[2024-11-15 13:59:58] AT%XCBAND=?
[2024-11-15 13:59:59] %XCBAND: (2,4,12,13)
[2024-11-15 13:59:59] OK
[2024-11-15 14:00:04] AT%XSYSTEMMODE=0,1,0,0
[2024-11-15 14:00:09] OK
[2024-11-15 14:00:10] AT%XCBAND=?
[2024-11-15 14:00:10] %XCBAND: (2,4,12,13,17)
[2024-11-15 14:00:10] OK
[2024-11-15 14:00:19] at+cfun=1
[2024-11-15 14:00:21] OK
[2024-11-15 14:00:21] AT%XCBAND=?
[2024-11-15 14:00:21] %XCBAND: (2,4,12,13,17)
[2024-11-15 14:00:21] OK
[2024-11-15 14:00:22] AT%XCBAND=?
[2024-11-15 14:00:22] %XCBAND: (2,4,12,13,17)
[2024-11-15 14:00:22] OK
[2024-11-15 14:00:23] AT%XCBAND=?
[2024-11-15 14:00:23] %XCBAND: (2,4,12,13,17)
[2024-11-15 14:00:23] OK
[2024-11-15 14:00:23] AT%XCBAND=?
[2024-11-15 14:00:23] %XCBAND: (2,4,12,13,17)
[2024-11-15 14:00:23] OK

Which modem fw are you running? This can be read out using "at+cgmr"

I was running this on mfw v1.3.6.

Kind regards,

Håkon

RE: problem about AT%XCBAND=?

William.wei — Fri, 15 Nov 2024 01:53:52 GMT

yes,Hakon

i understand your meaning, my point is band 17 is not listed at the first moment, but shows at about 10 seconds later.

we have any reason for this?

[quote userid="85273" url="~/f/nordic-q-a/116334/problem-about-at-xcband"]

[16:50:13.512] AT%XCBAND=?

[16:50:18.510]

[16:50:18.510] %XCBAND: (2,4,12,13)

[16:50:18.512]

[16:50:18.512] OK

[16:50:18.512] AT%XCBAND=?

[16:50:23.519]

[16:50:23.519] %XCBAND: (2,4,12,13,17)

[/quote]

Regards,

William.

RE: problem about AT%XCBAND=?

Håkon Alseth — Wed, 13 Nov 2024 10:27:30 GMT

Hi William,

We do not support band 17 on LTE-M, as stated here in the release notes for the mfw v1.3.6:

*** mfw_nrf9160_1.3.6
*********************

The mfw_nrf9160 is the firmware for the modem subsystem of nRF9160. It supports 3GPP LTE release 13
LTE-M and NB-IoT standards, selected optional 3GPP LTE release 14 features, GPS L1C/A and QZSS L1C/A
positioning.

LTE-M operation is enabled on E-UTRA Bands 1, 2, 3, 4, 5, 8, 12, 13, 18, 19, 20, 25, 26, 28 and 66.

NB-IoT operation is enabled on E-UTRA Bands 1, 2, 3, 4, 5, 8, 12, 13, 17, 19, 20, 25, 26, 28 and 66.

Also reflected here in the chart:

https://www.nordicsemi.com/Products/Wireless/Low-power-cellular-IoT/nRF9160-Revision-1-global-and-regulatory-certifications

Kind regards,

Håkon