M33 core in nRF9160 low power mode - Constant latency mode

RE: M33 core in nRF9160 low power mode - Constant latency mode

praveenpalaparthi — Wed, 22 Jul 2020 09:52:20 GMT

Hi SItan,

I am sorry for late response, I was held up with other work.

Though I haven't tested disabling CONFIG_BSD_LIBRARY, I was having a doubt that in SLM application CONFIG_BSD_LIBRARY is enabled and sleep mode current is getting around 4uA on the same nRF9160 dev kit.

With regards,

Praveen

RE: M33 core in nRF9160 low power mode - Constant latency mode

Stian Røed Hafskjold — Wed, 01 Jul 2020 18:59:49 GMT

Hi, I tried measuring your hex file, and I think I'm able to reproduce it with my own code here. Seems like the extra microamp is added when this is set in prj.conf:

CONFIG_BSD_LIBRARY=y

Can you check if that's the case, and try to remove it, and see if the current goes down?

I will start to investigate why enabling the BSD lib adds another 1uA to the measurements.

RE: M33 core in nRF9160 low power mode - Constant latency mode

praveenpalaparthi — Tue, 23 Jun 2020 16:55:59 GMT

Hi Stian,

Apologize for late response.

Here I am sending my hex filedevzone.nordicsemi.com/.../praveen_5F00_honeywell_5F00_lowpower.hex

RE: M33 core in nRF9160 low power mode - Constant latency mode

Stian Røed Hafskjold — Wed, 10 Jun 2020 13:26:49 GMT

Hi, can you please post your hex-file here where you get 6 uA? I can try to run it here and analyze what is going on. Maybe there is a k_sleep() in a loop waking up the chip regularly?

In the last plot you posted there is something happening around 4 seconds. Do you know what this is? With the hex I posted previously I do not expect to see any activity at all.

I'm currently looking into why you see 5uA on the DK and not 4uA. I see something similar here on a couple of DKs, so there is something on the DK that is leaking 1 uA I think. I will let you know what I find out.

RE: M33 core in nRF9160 low power mode - Constant latency mode

praveenpalaparthi — Tue, 09 Jun 2020 03:55:04 GMT

Hi,

Could you please help me understand what changes you made in hex file shared so that the same changes can be done in our project to get the current ~5uA.

--Praveen P

RE: M33 core in nRF9160 low power mode - Constant latency mode

praveenpalaparthi — Wed, 03 Jun 2020 07:13:14 GMT

I missed to upload log captured

RE: M33 core in nRF9160 low power mode - Constant latency mode

praveenpalaparthi — Mon, 01 Jun 2020 14:19:02 GMT

Hi Sitian

With the shared hex file I am seeing around ~5uA current.

...

there is lot of noise as you can see in the attached snapshot

RE: M33 core in nRF9160 low power mode - Constant latency mode

Stian Røed Hafskjold — Fri, 29 May 2020 15:09:49 GMT

Can you try flashing the following hex file? it should give you around 4 uA. If you see more then we need to check your measurement setup and see if you get any leakage current

devzone.nordicsemi.com/.../zephyr.hex

RE: M33 core in nRF9160 low power mode - Constant latency mode

praveenpalaparthi — Wed, 27 May 2020 08:25:28 GMT

Hi Sitan,

Yeah I am turning off modem using AT+CFUN=0. As of now I am not keeping the modem in PSM mode.

With regards,

Praveen P

RE: M33 core in nRF9160 low power mode - Constant latency mode

Stian Røed Hafskjold — Wed, 20 May 2020 10:41:31 GMT

Hi, is this when the modem is completely shut down or are you measuring PSM current? Modem shutdown to reach 1.8V is not implemented yet, so 4uA would be the minimum both in modem shutdown and in PSM idle mode.

RE: M33 core in nRF9160 low power mode - Constant latency mode

praveenpalaparthi — Wed, 13 May 2020 14:20:15 GMT

Hi Stian,

I have changed Vdd IO to 3V as suggested by you and found the current came down to 6uA from 9uA.

But I want to reach to the current consumption given in product spec doc v1.20 pg.59 and highlighted shown above.

I have few more queries on peripherals in low power mode to clarify, which I will create a new ticket.

Let us continue in this ticket only for current measurement.

RE: M33 core in nRF9160 low power mode - Constant latency mode

Stian Røed Hafskjold — Mon, 04 May 2020 09:52:23 GMT

Hi, there is a switch on the DK to select 3V. It's located next to the power switch. It's still fine to power the nRF9160 through the P24 connector at 3.7V.

RE: M33 core in nRF9160 low power mode - Constant latency mode

praveenpalaparthi — Wed, 29 Apr 2020 11:43:52 GMT

Okay can you please help me how to set Vdd IO to 3V......

I am externally powering nRF9160 soc on P24 connector with 3.7V

RE: M33 core in nRF9160 low power mode - Constant latency mode

Heidi — Wed, 29 Apr 2020 11:38:58 GMT

Hi, you should still sett VDD IO to 3V as you could be losing ~3 uA from leakage.

RE: M33 core in nRF9160 low power mode - Constant latency mode

praveenpalaparthi — Wed, 29 Apr 2020 11:29:01 GMT

Hi,

Thanks for info, but at present I didn't enabled PSM I nRF9160.

RE: M33 core in nRF9160 low power mode - Constant latency mode

Heidi — Wed, 29 Apr 2020 10:28:29 GMT

Perhaps shutting down BSD lib was preventing one of the threads from going to sleep? I will have a closer look today.

Side note: when you're measuring on the DK, VDD IO should be set to 3V to get 4uA as the floor current in PSM. It's a workaround for a current leak that occurs if VDD IO is in 1.8 V.

RE: M33 core in nRF9160 low power mode - Constant latency mode

praveenpalaparthi — Tue, 28 Apr 2020 13:29:57 GMT

Hi Heidi,

What I observed is that if I commented bsd_shutdown(); in my project, I am able to see the average current consumption is around 8uA.

I am not able to understand the behavior why after commenting bsd_shutdown, current drooped to 8 uA.

RE: M33 core in nRF9160 low power mode - Constant latency mode

praveenpalaparthi — Tue, 28 Apr 2020 13:21:45 GMT

I am in master branch. attached YML file

devzone.nordicsemi.com/.../west.txt

RE: M33 core in nRF9160 low power mode - Constant latency mode

Heidi — Tue, 28 Apr 2020 12:40:23 GMT

Hi, if you're still seeing 2.92 mA, it's probably because one of the threads in the project isn't going to sleep, hence not allowing the idle thread to enter system idle mode.

I'm trying to build the project and then using SES debugging to see if this is the case, but I'm having trouble opening the project in SES. I was able to build it using the command line (west build) but I did see a few warnings.

What NCS tag are you using?

RE: M33 core in nRF9160 low power mode - Constant latency mode

praveenpalaparthi — Tue, 28 Apr 2020 09:06:18 GMT

devzone.nordicsemi.com/.../nrf91_5F00_lowPOwerMode.txt

I have uploaded my complete project.Please rename file extension to *.zip and extract the project.

Could you please let me know where I m going wrong

RE: M33 core in nRF9160 low power mode - Constant latency mode

praveenpalaparthi — Tue, 28 Apr 2020 09:03:54 GMT

Hi Heidi,

I have tried the code given COmmon_fixed.c and 1641.prj.txt and measured current.

It is around 2.92mA

RE: M33 core in nRF9160 low power mode - Constant latency mode

Heidi — Mon, 27 Apr 2020 12:31:31 GMT

Hi!

Okay, I understand. I received help from a colleague to fix a few things in the code you sent over:

devzone.nordicsemi.com/.../Common_5F00_fixed.c

Could you try this instead and see if it helps with the power consumption?

I missed a note at the bottom of the CPU Idling documentation: Do not use these APIs unless absolutely necessary. In a normal system, the idle thread takes care of power management, including CPU idling.

According to the Zephyr Threads documentation if all threads are unready, the Zephyr idle thread will set the CPU in System ON Idle. So it will either happen automatically, or you can set k_sleep() for a certain amount of time. More information on the idle thread can be found here.

Which is why this function has been removed from the code.

Best regards,

Heidi

RE: M33 core in nRF9160 low power mode - Constant latency mode

praveenpalaparthi — Fri, 24 Apr 2020 12:55:02 GMT

Hi Heidi,

Yeah, I just replied to that mail chain.

Again here I am copying the same :-)

Still we are not clear on the end application use case( Modem should be ON with PSM or completely OFF), as of now we want to evaluate power consumption of M33 core. May be after getting hands on low power states of M33 core in SoC, we will evaluate Modem ON Idle mode with PSM, Modem ON idle mode without PSM then conclude the best possible approach.

We are working in gas meter application. We have two modes of operation

1. TCP client mode we call it as CALL-IN mode.

2.TCP server mode we call it as CALL-OUT mode/continuous server mode.

In CALL-IN mode we are not always connected to network, we will turn of the radio. If we get request from gas meter to connect to network and transfer the data to headend system(cloud), we will wakeup M33 core and turn on nRF9160 radio in SoC, register to network, transfer data to cloud then switch off the radio and move the M33 core to sleep.For this use case we are trying to evulate sleep modes in M33 core.

As martin suggested approach is good and best suited for our CALL-IN mode. We will consider it but before we want to have a hands on sleep mode in M33 core in SoC.

Coming to CALL-OUT mode or continuous server mode, nRF9160 radio will always connected to network and with eDRX enabled. If there is no data transaction on the network, nRF9160 will move to eDRX mode and M33 core should also move to sleep mode. If a remote client connection request comes to radio nRF9160 in paging time window, radio internally should wake up M33 core for processing data received.

RE: M33 core in nRF9160 low power mode - Constant latency mode

Heidi — Fri, 24 Apr 2020 12:29:46 GMT

Hi!

No, setting %XDATAPRFL won't have a large impact as you can read from the application note:

As Martin mentioned in the email thread, it looks like your CPU is still running.

However, I think the optimal situation for your use-case would be to keep the modem turned on, in power-saving mode, for lower overall power consumption. Turning the modem off means every time you want to transmit or receive, you need to turn the modem back on and re-attach to the network which takes a lot of power compared to having the modem in PSM, which has a floor-current of 4 uA.

You can use the lte_lc_psm_req(bool enable) function to go to or disable PSM.

Best regards,

Heidi

RE: M33 core in nRF9160 low power mode - Constant latency mode

praveenpalaparthi — Thu, 23 Apr 2020 05:41:21 GMT

Do I also need to set application data profile in low power mode

%XDATAPRFL=<power_level>

0 – Ultra-low power

1 – Low power

2 – Normal

3 – Performance

4 – High performance