SoftDevice temperature acquisition

RE: SoftDevice temperature acquisition

SebastienTE — Mon, 27 Nov 2023 08:59:01 GMT

Hi Einar,

Thank you very much for your answer.

Sebastien

RE: SoftDevice temperature acquisition

Einar Thorsrud — Mon, 27 Nov 2023 08:06:57 GMT

These registers are not documented publicly other than that they exist. They are not intended to be manipulated though, and should hold data from FICR. This is handled during startup (see erratum 66 and code writing to NRF_TEMP in system_nrf52.c).

RE: SoftDevice temperature acquisition

SebastienTE — Fri, 24 Nov 2023 16:28:52 GMT

Hello Einar, thanks a lot for your answer.

And about registers related to TEMP (piecewise linear function), what we have to do with these registers?

RE: SoftDevice temperature acquisition

Einar Thorsrud — Fri, 24 Nov 2023 13:23:07 GMT

Hi,

The SoftDevice will not start the HFXO automatically when you call sd_temp_get(), so it is your responsibility to do that.

Regarding calibration, if using the LFRC the SoftDevice will take temperature into account to decite if it needs to calibrate the LFRC or not (see relevant configurations for that here). That is the only thing the SoftDevice use temperature for.

The temperature sensor on the nRF devices is primerily indended for use as in the case above, and therefor is not calibrated across temperature ranges. It is fairly good to detect changes in temperature, but not so much for measuring absolute temperatures. (See TEMP electrical specifications for details).