Thingy91X npm1300 fuel gauge sample configuration/build problem

RE: Thingy91X npm1300 fuel gauge sample configuration/build problem

Achim Kraus — Fri, 05 Sep 2025 05:20:37 GMT

Thanks for the link to the asset-tracker-template, seems that contains the battery model.

To be frank, I don't think, that using the nRF53 for the fuel guage is easy, if possible at all.

The Thingy:91X uses i2c a lot from the nRF91 and I'm not aware, that i2c supports a "multi-master-mode".

> BLE and the battery service

My plan was to use it for a better battery level value, but I send that over cellular to my server. As I wrote above, I don't think it makes sense to change the app in a way, to make the nRF53 the i2c master instead of the nRF91. What I would try (but I don't need that on the BLE) is to enable the i2c device mode on the nRF53 and then transfer the battery level to that nRF53.

RE: Thingy91X npm1300 fuel gauge sample configuration/build problem

sd30 — Thu, 04 Sep 2025 21:19:13 GMT

Update. I was able to get battery SOC data using the asset tracker example which does support the Thingy-91X;

https://docs.nordicsemi.com/bundle/asset-tracker-template-latest/page/index.html

This code builds for thingy91x/nrf9151/ns and ideally we'd like to run on the nrf53 since that's supporting BLE and the battery service.

The SOC values seem OK in limited testing but I take Achim's point that a battery model 91X would be needed.

Regarding Mathiaso "reconfiguration procedure that gives the nRF53 control of the I2C" - any more info on this? Perhaps that is why the build above fails? - lack of reconfiguration of the i2c bus from '91 to '53?

BTW I had already made the DEVICE_DT* changes to the fuel gauge sample to use the 91x names;

npm1300_fuel_gauge/src/main.c;

#ifdef TEST_ON_91X_NRF53 // build fails

static const struct device *pmic = DEVICE_DT_GET(DT_NODELABEL(pmic_main));

static const struct device *charger = DEVICE_DT_GET(DT_NODELABEL(npm1300_charger));

#else // works for nrf5340dk_nrf5340_cpuapp

static const struct device *pmic = DEVICE_DT_GET(DT_NODELABEL(npm1300_ek_pmic));

static const struct device *charger = DEVICE_DT_GET(DT_NODELABEL(npm1300_ek_charger));

#endif

and above you see if created thingy91x_nrf5340_cpuapp.overlay

RE: Thingy91X npm1300 fuel gauge sample configuration/build problem

mathiaso — Tue, 02 Sep 2025 08:57:57 GMT

I've received some feedback now, Richard.

Supposedly, it is difficult to do what you want, as we on the Thingy:91 X don't show how to use the nRF53 as anything else than a connectivity bridge (other than a proof-of-concept config of wifi shell).

I've been told that there should be two ways to go at this.

Either use the nRF53 as a BLE controller, with the host running on the nRF91.
Or do the reconfiguration procedure that gives the nRF53 control of the I2C and SPI buses. There are device tree overlays in the board files for this. Also, additional partition tables, since external flash belongs to the chip who owns the SPI.

All of this is highly experimental and not documented, I'm afraid.

RE: Thingy91X npm1300 fuel gauge sample configuration/build problem

Achim Kraus — Thu, 28 Aug 2025 18:46:33 GMT

Some hints, though I considered the same, but withdrawn it:

AFAIK, there is no battery model for the 1350mAh battery used in the Thingy:91X, only other/smaller batteries are available. Without that model, the result may be not that good, if useful at all.

It may be easier to copy the "battery_model.inc", "fuel_gauge.c" and "fuel_gauge.h" to a Thingy:91X project and add that there to the "CMakeLists.txt".

The code in "main.c" must the be also added to that Thingy:91X project. The npm1300 devices must then be

static const struct device *pmic = DEVICE_DT_GET(DT_NODELABEL(pmic_main));
static const struct device *charger = DEVICE_DT_GET(DT_NODELABEL(npm1300_charger));

instead of "npm1300_ek_pmic" and "npm1300_ek_charger" or, alternative you will need to add those label in an overlay, e.g. "thingy91x_nrf9151_ns.overlay"

npm1300_ek_pmic: &pmic_main {

};

npm1300_ek_charger: &npm1300_charger {

};

RE: Thingy91X npm1300 fuel gauge sample configuration/build problem

sd30 — Thu, 28 Aug 2025 13:38:55 GMT

Thanks Mathias,

In the meantime are there any links or suggestions how to resolve the build errors?

RE: Thingy91X npm1300 fuel gauge sample configuration/build problem

mathiaso — Thu, 28 Aug 2025 13:26:15 GMT

Ok. I'm currently not aware of such a sample, but I've asked the Thingy:91 X team if there is one, or if not, if there are any other samples that may be good starting points for achieving this.

RE: Thingy91X npm1300 fuel gauge sample configuration/build problem

sd30 — Wed, 27 Aug 2025 15:02:00 GMT

Hi Mathias,

Looking to get battery SOC from the pmic for a BLE BAS service on Thingy-91x. That would be a useful sample for most users of this very nice board.

RE: Thingy91X npm1300 fuel gauge sample configuration/build problem

mathiaso — Wed, 27 Aug 2025 13:29:54 GMT

Hi, Richard.

Is it fuel gauging you want to do? If so, you should use the use the nPM1300 EK with the nPM Fuel Gauge Board.

Best regards,
Mathias