NRF9160 POFWARN

RE: NRF9160 POFWARN

Thomas — Fri, 06 Nov 2020 14:32:36 GMT

Thanks for all the helpful Simon! It is great to hear it will be added to the MDK and PS.

RE: NRF9160 POFWARN

Simonr — Fri, 06 Nov 2020 13:52:07 GMT

Hi again Thomas

Latest update from our experts internally:

As of now, you will have to use the %XPOFWARN AT command and get the power off warning through the modem. Please note that the minimum level should not be set below 3V as the PMIC will cut the power to the SoC at ~2.95V (depending on the operating conditions). The minimum supply level on the nRF9160 is 3V as stated in the product specification, and we will update the AT command guide as soon as possible to better communicate this.

As for the EXTPOFCON feature/registers where the application can get power off warning events directly, we are in progress of documenting this in the PS and adding it to MDK.

Best regards,

Simon

RE: NRF9160 POFWARN

Thomas — Fri, 06 Nov 2020 02:13:57 GMT

Thank you Simon

RE: NRF9160 POFWARN

Simonr — Thu, 05 Nov 2020 11:40:39 GMT

Hi Thomas,

I have not gotten a "final" resolution from the R&D guys yet, but I asked them when, and they expect to have a finite answer by tomorrow. Thank you so much for your patience, and I apologize about the delay. This took longer to get to the bottom of than any of us imagined.

Best regards,

Simon

RE: NRF9160 POFWARN

Thomas — Thu, 05 Nov 2020 08:23:09 GMT

Any updates on this Simon?

Kind regards,

Thomas

RE: NRF9160 POFWARN

Thomas — Mon, 26 Oct 2020 13:37:40 GMT

Okay thanks Simon. I’m confused as to why it isn’t in the specification as the POFWARN event that is triggered by this is in the specification but this not.

RE: NRF9160 POFWARN

Simonr — Mon, 26 Oct 2020 12:35:26 GMT

Hi Thomas

We would not suggest doing anything not defined in the specification itself. I have to get word back internally regarding this register, so please stand by until I get back to you.

Best regards,

Simon

RE: NRF9160 POFWARN

Thomas — Fri, 23 Oct 2020 06:25:05 GMT

Hi Simon,

I have discovered you can set your own clock driver using CONFIG_CLOCK_CONTROL_NRF_FORCE_ALT. So I now have access to the interrupt.

Can I please get confirmation on the layout of the register? From what I can gather:

1) It is at location 0x40004510

2) Bit 0 is used to turn the it on/off

3) Bits 1-4 control the threshold with 0 being 1.3V and the LSB being 0.1V

4) When the threshold is crossed the POFWARN event is triggered

5) Internally the chip runs at 2.2V so the level must be set lower than that to work correctly

I am using this on the B0 version and it is running correctly. There is no difference with the B1 version correct? We will be building tens of thousands at a time so I need to ensure the hardware versions will behave the same.

Kind regards,

Thomas

RE: NRF9160 POFWARN

Simonr — Thu, 22 Oct 2020 08:12:53 GMT

Hi Thomas

Revision 1 and 2 are different in this respect:

Rev. 1 does not really have a POF mechanism, but you can monitor battery voltage "manually" by requesting info and notifications dynamically from modem via the AT command %XVBAT, There's no POF specific reset generated.
Rev. 2 has an additional POF service feature through the modem AT command %XPOFWARN. There's still no specific POF reset generated though.
Both Rev. 1 and 2 will generate a BOR when the SiP's internal voltage drops below the BOR limit (PS chapter "5.1.3.4.2 Power supply supervisor")
PS chapter "5.3.1.1.14 RESETREAS" states that "If none of the reset sources are flagged, this indicates that the chip was reset from the on-chip reset generator, which will indicate a power-on reset or a brownout reset." This goes for both revisions.

Best regards.

Simon

RE: NRF9160 POFWARN

Thomas — Wed, 21 Oct 2020 10:59:27 GMT

Right I didn’t see that note in the manual, I am using B0 which would explain it. So a way to differentiate brown out resets on both hardware revision would be ideal.

Kind regards,

Thomas

RE: NRF9160 POFWARN

Simonr — Wed, 21 Oct 2020 10:40:35 GMT

Hi Thomas

Just to clarify, you are using a revision of the nRF9160 that supports external Power off warnings, right? The %XPOFWARN command is supported by revision nRF9160-SIxA-B1 and newer.

Best regards,

Simon

RE: NRF9160 POFWARN

Thomas — Wed, 21 Oct 2020 03:26:46 GMT

Thanks for looking into this Simon.

Is this what you are after?

RE: NRF9160 POFWARN

Simonr — Tue, 20 Oct 2020 11:39:30 GMT

Thank you for the updates Thomas. We're currently looking into both the BOR versus power on resets and the %XPOFWARN AT command. I will update you with the progress as soon as possible, but it might be a few days. Thank you for your patience.

Best regards,

Simon

UPDATE: AT%XPOFWARN is not available in mfw v1.2.0, but should definitely be available for mfw v1.2.1 and onwards. Can you provide an AT sequence log similar to the one below where you're using mfw v1.2.1?

14:54:43 AT%XMODEMUUID
14:54:43 %XMODEMUUID: c75da334-ae89-4e54-b5ad-bab013c787f2
OK
14:55:31 AT+CGMR
14:55:32 mfwRD_nrf9160_1.2.2-163.rc
OK
14:55:50 AT%XPOFWARN=1,30
14:55:51 OK
14:56:45 AT%XPOFWARN=1,31
14:56:45 OK
14:56:54 AT%XPOFWARN=1,32
14:56:54 OK

RE: NRF9160 POFWARN

Thomas — Tue, 20 Oct 2020 08:30:24 GMT

Also %XPOFWARN is not available on the version 1.2.x modem firmware. It says it is in the manual and it appears in the CLAC list but attempts to set it fail

RE: NRF9160 POFWARN

Thomas — Mon, 19 Oct 2020 06:08:40 GMT

I see, then how are we meant to be able to detect brownouts? I was planning on using the interrupt to quickly set one of the general purpose registers and reset the system. Without something like that and with no differentiation between power on and brown out resets in the reset reason register I am at a loss.

RE: NRF9160 POFWARN

Simonr — Mon, 19 Oct 2020 06:02:02 GMT

Hi Thomas

Sorry for the late reply, but it took some time getting an official statement on this. The POFCON register can be found in nRF91 projects because the power failure warning mechanism is supported as an AT-command from MFW v1.2.1 and onwards. It is described in documentation format in the nRF91 AT Commands reference guide (section 5.27 External Power off warnings %XPOFWARN).

Best regards,

Simon

RE: NRF9160 POFWARN

Simonr — Fri, 09 Oct 2020 10:59:41 GMT

Hi Thomas

We will likely update to the latest Zephyr version when the next NCS version is released, but I can't provide any information as to when this will be, as we never speculate in or discuss upcoming releases here on the DevZone. For details or a roadmap on the matter, please contact the RSM of your area. If you don't know who this is, please let me know and I'll help you get in touch.

There has not been any updates on the POFCON register as of yet.

Best regards,

Simon

RE: NRF9160 POFWARN

Thomas — Fri, 09 Oct 2020 07:36:20 GMT

It looks like this might be fixed in the latest version of zephyr, but in v1.3.0 and v1.3.1 of the SDK the zephyr version used is 2.3. RC1, but the trunk is up to v2.4.0. When do you update the zephyr version in your tagged SDK releases?

RE: NRF9160 POFWARN

Thomas — Fri, 09 Oct 2020 06:58:57 GMT

Hi Simon, the interrupt for the clock and power are shared and is being used in nrf_power_clock, so I can enable the interrupt but can't get access to the callback. I am using v1.3.0

RE: NRF9160 POFWARN

Simonr — Fri, 09 Oct 2020 06:56:25 GMT

Hi again,

I'm sorry, but I'm not sure I understand? I can't see where the POFWARN interrupt is used by nrf_power_clock.c. What version of the nRFConnect SDK (NCS) are you using?

Best regards,

Simon

RE: NRF9160 POFWARN

Thomas — Thu, 08 Oct 2020 07:17:54 GMT

Hi Simon, how can this work if nrf_power_clock is already using the interrupt?

RE: NRF9160 POFWARN

Thomas — Mon, 05 Oct 2020 01:28:49 GMT

Thank you Simon

RE: NRF9160 POFWARN

Simonr — Fri, 02 Oct 2020 10:30:26 GMT

Hi Thomas,

The easiest way to make use of the POFWARN interrupt should be either nrfx_power_pof_init() or nrfx_power_pof_enable() depending on whether CONFIG_NRFX_POWER is set to Y or N.

As for the POFCON register you're seeing, it indeed seems like a mishap on our side, I have reported this missing documentation internally, and I'll get back to you with any progress on the matter.

Best regards,

Simon

RE: NRF9160 POFWARN

Thomas — Fri, 02 Oct 2020 06:58:43 GMT

Hi Simonr, this is on a custom board, so it can only be the nrf9160, and I have played around with it and it does seem to behave as expected?

RE: NRF9160 POFWARN

Simonr — Fri, 02 Oct 2020 06:48:33 GMT

Hi Thomas

The POFCON register refers to the Power Failure Comparator found in the nRF5x series. I assume the register you're seeing is found in the nRF52 control chip that I.E. the nRF9160DK uses for board control.

I will have to look into the POFWARN possibilities, but I'll get back to you with an update soon.

Best regards,

Simon