NRF9160 Low power

RE: NRF9160 Low power

Bjørn Kvaale — Tue, 10 Sep 2019 08:52:12 GMT

[quote user="Hadrien Kohl"] Is it correct to assume the modem will continue to send notifications, preventing the MCU to go into deep sleep?[/quote]

The CEREG command subscribes unsolicited network status notifications. That basically means that you can see what kind of network parameters the User Equipment (nRF91) discussed with the base station. Have you already set PSM? The MCU will go into deep sleep if it has nothing else to do. If the FW comes out of k_cpu_idle() every 20 seconds or so, something is waking it up. I do not believe it is the CEREG command. Is the eDRX interval set? Check by setting CEREG to 4 to see Active Time & Periodic Tau.

[quote user="Hadrien Kohl"]I saw somewhere on the forum a trick to disable rx/uart? Could this be related?[/quote]

I doubt it, but it may be worth a try.

[quote user="Hadrien Kohl"]Is it enough to send AT+CPSMS= or do I need to send AT+CFUN=0, AT+CPSMS= and then AT+CFUN=1?[/quote]

I am not sure you need to disable PSM when triggering a FOTA.

RE: NRF9160 Low power

Bjørn Kvaale — Tue, 10 Sep 2019 07:31:25 GMT

[quote user="Hadrien Kohl"]Regarding requesting eDRX or PSM, I suppose it would be possible to get feedback from the modem right? I'd expect the lte_lc_psm_req() and lte_lc_edrx_req() to signal that they failed the negociation. I could give it a go. Are you open to PRs?[/quote]

Yes, take a look at the CEREG function for that after you have set the PSM mode. If you set CEREG to 4, you should be able to see the active time & periodic tau for PSM. Yes, we are open to PRs.

RE: NRF9160 Low power

Bjørn Kvaale — Tue, 10 Sep 2019 07:29:07 GMT

AFAIK, iBasis does not support PSM mode in Norway. You'll need to try with a Telenor or Telia SIM card instead in Norway.

RE: NRF9160 Low power

Hadrien Kohl — Sun, 08 Sep 2019 12:22:15 GMT

Seems iBasis does not support PSM. At least according to https://devzone.nordicsemi.com/f/nordic-q-a/48641/psm-tau-and-at/196848#196848

I made some tests and none of the PSM parameters I tried worked:

[00:00:07.919,403] <dbg> at_cmd.at_write: Sending command AT+CEREG=5
[00:00:07.926,544] <dbg> at_cmd.socket_thread_fn: Received command: OK

[00:00:07.939,758] <dbg> at_cmd.at_write: Sending command AT+CPSMS=1,,,"00000001",
[00:00:07.949,005] <dbg> at_cmd.socket_thread_fn: Received command: OK

[00:00:09.968,811] <dbg> at_cmd.at_write: Sending command AT+CEREG?
[00:00:09.976,043] <dbg> at_cmd.socket_thread_fn: Received command: +CEREG: 5,5,"7789","01039801",7,,,"11100000","11100000"

[00:00:11.000,030] <dbg> at_cmd.at_write: Sending command AT+CPSMS=1,,,"00100001",
[00:00:11.016,906] <dbg> at_cmd.socket_thread_fn: Received command: OK

[00:00:13.031,280] <dbg> at_cmd.at_write: Sending command AT+CEREG?
[00:00:13.046,875] <dbg> at_cmd.socket_thread_fn: Received command: +CEREG: 5,5,"7789","01039801",7,,,"11100000","11100000"

[00:00:14.070,343] <dbg> at_cmd.at_write: Sending command AT+CPSMS=1,,,"01000001",
[00:00:14.087,127] <dbg> at_cmd.socket_thread_fn: Received command: OK

[00:00:16.101,593] <dbg> at_cmd.at_write: Sending command AT+CEREG?
[00:00:16.117,340] <dbg> at_cmd.socket_thread_fn: Received command: +CEREG: 5,5,"7789","01039801",7,,,"11100000","11100000"

[00:00:17.140,655] <dbg> at_cmd.at_write: Sending command AT+CPSMS=1,,,"01100001",
[00:00:17.157,501] <dbg> at_cmd.socket_thread_fn: Received command: OK

[00:00:19.171,905] <dbg> at_cmd.at_write: Sending command AT+CEREG?
[00:00:19.187,652] <dbg> at_cmd.socket_thread_fn: Received command: +CEREG: 5,5,"7789","01039801",7,,,"11100000","11100000"

[00:00:20.210,998] <dbg> at_cmd.at_write: Sending command AT+CPSMS=1,,,"10000001",
[00:00:20.219,635] <dbg> at_cmd.socket_thread_fn: Received command: OK

[00:00:22.234,436] <dbg> at_cmd.at_write: Sending command AT+CEREG?
[00:00:22.250,030] <dbg> at_cmd.socket_thread_fn: Received command: +CEREG: 5,5,"7789","01039801",7,,,"11100000","11100000"

[00:00:23.273,468] <dbg> at_cmd.at_write: Sending command AT+CPSMS=1,,,"10100001",
[00:00:23.281,951] <dbg> at_cmd.socket_thread_fn: Received command: OK

[00:00:25.296,905] <dbg> at_cmd.at_write: Sending command AT+CEREG?
[00:00:25.312,561] <dbg> at_cmd.socket_thread_fn: Received command: +CEREG: 5,5,"7789","01039801",7,,,"11100000","11100000"

[00:00:26.335,968] <dbg> at_cmd.at_write: Sending command AT+CPSMS=1,,,"11000001",
[00:00:26.353,820] <dbg> at_cmd.socket_thread_fn: Received command: OK

[00:00:28.367,218] <dbg> at_cmd.at_write: Sending command AT+CEREG?
[00:00:28.374,450] <dbg> at_cmd.socket_thread_fn: Received command: +CEREG: 5,5,"7789","01039801",7,,,"11100000","11100000"

[00:00:29.398,468] <dbg> at_cmd.at_write: Sending command AT+CPSMS=1,,,"11100001",

[00:00:31.429,718] <dbg> at_cmd.at_write: Sending command AT+CEREG?
[00:00:31.436,950] <dbg> at_cmd.socket_thread_fn: Received command: +CEREG: 5,5,"7789","01039801",7,,,"11100000","11100000"

Are you in contact with iBasis? Do you know if they are planning on supporting the PSM/eDRX mode soon?

RE: NRF9160 Low power

Hadrien Kohl — Fri, 06 Sep 2019 15:48:32 GMT

Hi again.

Looking at the link control (lte_lc.c) it seems the network registration is not disabled (AT+CEREG=0) in the method w_lte_lc_init_and_connect(). Is it correct to assume the modem will continue to send notifications, preventing the MCU to go into deep sleep? Is is kind of consistent with the tests I did where I saw the firmware come out of k_cpu_idle(); ar regular intervals (~20 seconds).

I saw somewhere on the forum a trick to disable rx/uart? Could this be related?

I am trying to enable disable the PSM/eDRX when I trigger a FOTA update. Is it enough to send AT+CPSMS= or do I need to send AT+CFUN=0, AT+CPSMS= and then AT+CFUN=1?

RE: NRF9160 Low power

Hadrien Kohl — Wed, 04 Sep 2019 21:16:08 GMT

[quote userid="25682" url="~/f/nordic-q-a/51513/nrf9160-low-power/207595"]

Hadrien Kohl said:
Shouldn't the connection fail at some point?

No, because you can still have a connection without PSM mode on. You just won't get a GPS position without PSM mode however.

[/quote]

I meant when connecting using nb-iot and the iBasis SIM. I never get out of the lte_lc_init_and_connect() function. I think I've let it run overnight.

Regarding requesting eDRX or PSM, I suppose it would be possible to get feedback from the modem right? I'd expect the lte_lc_psm_req() and lte_lc_edrx_req() to signal that they failed the negociation. I could give it a go. Are you open to PRs?

[quote userid="25682" url="~/f/nordic-q-a/51513/nrf9160-low-power/207595"][/quote]

Hadrien Kohl said:

I did disable serial and trace options both in the mcuboot and spm modules and my application (is there a way to do so via the prj.conf by the way?

Yes, set CONFIG_SERIAL=n. See this blog post for more info. Are you referring to a modem trace or just regular app loggging?

I am using spm and mcuboot. I'd like to disable the CONFIG_SERIAL option in those from my application.

I am refering to BSD_TRACE. I have read that this could help.[quote userid="25682" url="~/f/nordic-q-a/51513/nrf9160-low-power/207595"][/quote]

Hadrien Kohl said:

Appart from PWM, do you have current consumption values for the different modules of the chip?

Have you taken a look at the product specification for the nRF9160?

I'll give it another look.

RE: NRF9160 Low power

Bjørn Kvaale — Tue, 03 Sep 2019 08:41:00 GMT

[quote user="Hadrien Kohl"]Wasnt it supported at some point in the past?[/quote]

Not sure. Maybe, but I doubt it.

Hadrien Kohl said:

Shouldn't the connection fail at some point?

No, because you can still have a connection without PSM mode on. You just won't get a GPS position without PSM mode however.

Hadrien Kohl said:

I did disable serial and trace options both in the mcuboot and spm modules and my application (is there a way to do so via the prj.conf by the way?

Yes, set CONFIG_SERIAL=n. See this blog post for more info. Are you referring to a modem trace or just regular app loggging?

Hadrien Kohl said:

Maybe the flash access of the mcuboot is drawing current after the switch to spm/app?

I doubt it, but maybe.

Hadrien Kohl said:

Is the whole device power management feature something you are still working on?

Not sure. I would ask your local Regional Sales Manager.

Hadrien Kohl said:

Appart from PWM, do you have current consumption values for the different modules of the chip?

Have you taken a look at the product specification for the nRF9160?

RE: NRF9160 Low power

Hadrien Kohl — Fri, 30 Aug 2019 10:25:27 GMT

Ok, that makes sense. Wasnt it supported at some point in the past?

Shouldn't the connection fail at some point? I am using the lte_ functions to connect.

I will try the PSM and measure again.

I did disable serial and trace options both in the mcuboot and spm modules and my application (is there a way to do so via the prj.conf by the way? Right now I have to use mcuboot_menuconfig and spm_menuconfig each time).

Maybe the flash access of the mcuboot is drawing current after the switch to spm/app?

I saw the nrf_pwm module has some power management hooks already. Is the whole device power management feature something you are still working on? I am asking because I could try to implement some of it myself.

Appart from PWM, do you have current consumption values for the different modules of the chip?

Thank you for your help.

RE: NRF9160 Low power

Bjørn Kvaale — Fri, 30 Aug 2019 10:12:02 GMT

Hi Hadrien,

iBasis does not support nB-IoT here in Norway. You will either need to use a Telia or Telenor SIM card in Norway.

[quote user="Hadrien Kohl"]Is is correct to assume that I could use lte-m with power saving mode and achieve low power usage as well? The difference is that the 91 won't be reachable at all right?[/quote]

Yes, you can use LTE-M1 or nB with PSM mode. Just make sure to choose an interval >= 10 minutes. I would try ten minutes first The network might not approve of all intervals, so be sure to use the AT+CEREG=5 & then AT+CEREG? to see whether the PSM intervals have been set correctly.

[quote user="Hadrien Kohl"]I managed to measure 20uA without turning on the modem and calling k_cpu_idle in a loop. That's still 480 uA from what I am measuring in our application firmware.[/quote]

Did you use the blog post example app to test with? Do you have logging enabled in your app? Take a look at the blog post one more time & make sure you have done what is stated there.

RE: NRF9160 Low power

Hadrien Kohl — Fri, 30 Aug 2019 08:33:02 GMT

Hi Bjørn,

Turns out the nb-iot mode doesn't work at all. I tested the same parameters as in the sample and then the sample itself. I was able to use nb-iot mode before upgrading the modem fw to 1.0.0. I did not investigate further since lte-m worked fine.

Is there a way to diagnose why the modem won't connect in nb-iot mode? Could it be that the tower won't accept the period that is requested?

Is is correct to assume that I could use lte-m with power saving mode and achieve low power usage as well? The difference is that the 91 won't be reachable at all right?

I managed to measure 20uA without turning on the modem and calling k_cpu_idle in a loop. That's still 480 uA from what I am measuring in our application firmware. I'll make some test enabling/disabling the PWM modules and keep you posted.

Hadrien

RE: NRF9160 Low power

Hadrien Kohl — Thu, 29 Aug 2019 14:00:18 GMT

Hi Bjørn,

Yes. I tried with the hex file in the blog post. I also compiled the code written in the blog and the sample in the Rallare/fw-nrfconnect-nrf branch.

I am using the iBasis sim card that comes with the kit. I will try PSM and eDRX and measure again.

RE: NRF9160 Low power

Bjørn Kvaale — Thu, 29 Aug 2019 13:20:17 GMT

Have you taken a look at this blog post yet? Included is a project file, which should work out of the box on the 91 DK. What kind of SIM card are you using? Have you set PSM mode? This DevZone case could be helpful.