HFXO _INTCAP setting

[MURAKAMI KAZUHIRO]

I want to adjust the HFXO capacitance using INTCAP.

When the XOSC32MTRIM.SLOPE (chip-specific factory calibration value) is small, the resolution of INTCAP becomes coarse, which may prevent fine adjustment. Depending on the chip, it may not be possible to achieve fine tuning, potentially causing the recommended tolerance of ±40 ppm for BLE operation to be exceeded.

Are there any countermeasures for this case?

[MURAKAMI KAZUHIRO]

Could you please explain the calculation method, configuration method, and any precautions when using them together?

[Ressa]

Hi,

Please check the HW design guideline recently released for 54L series, it has a separate chapter for HFXO and ways to calculate and set load caps:


ngl_001.pdf • Viewer • Technical Documentation


I am still not sure why you are that concerned about caps resolution, with only internal caps (and its resolution and the trim variations) you can easily stay within 40 ppm requirements. 

Best regards,
Ressa

[MURAKAMI KAZUHIRO]

Thank you for the HW design guideline.

I apologize for the confusion.

Although the settings may end up being the same, we found that—due to a calculation error in the measurement results—it can be set within 40 ppm.


best regards,