Problems with RF Frequency Bias Calibration

[emmovo]

I would like to understand the issue of frequency offset calibration in RF signals, I have viewed the

• Case ID: 309794
• nwp_006.pdf

I would like to know if I can do a frequency bias calibration by adjusting the load capacitors inside the chip when I test the RF out of the expected range. If so, is it possible to adjust the "FICR->XOSC32MTRIM.OFFSET"
register directly or is there an API interface specifically for frequency offset calibration? 

[ketiljo]

You set this in Kconfig:

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/kconfig/index.html#CONFIG_SOC_HFXO_CAP_INT_VALUE_X2

Select the capacitor value as you would with external caps: Ccap = CL * 2 - 2.5 pF

The Kconfig is set to double this value

[emmovo]

If I want to perform frequency offset calibration in production test, based on the actual measured frequency offset value of each piece of dut in conjunction with the production test firmware, how should I implement this calibration action in my production test firmware; and is there any other method other than the one configured by kconfig?

[ketiljo]

You don't have to do production trimming. This is a one time design config.