How to change 32Mhz crystal Xtaltrim value in HWparemeter

[Annie_he]

Hi NXP,

    Now we are developing bluetooth board with KW45. And we meet a problem is that the frequency error of our dut is about 50 Khz, it is out of the limit (-20, 20)ppm. So now we want to change the internal capacitor to tune the frequency and to get more presice one.

Here is our default Frequency error=57.6 Khz.

      And we want to change the interal capacitor value to get more presice Frequency. We found HWParameter in HCI_black box project can change this value and it can be store in NBU, which will not be change even if we change FW in dut. 

      and this is the defalut code in HWParameter.h, Please help us to change the value, we really need your help, thanks!

Please help us to change the value, we really need your help, thanks!

[Ricardo_Zamora]

Hello,

Could you please confirm that you are using a NXP recommended 32MHz crystal?

Also, maybe this community post might be helpful:

KW45/K32W1 32MHz & 32kHz Oscilllation margins - NXP Community

Regards,

Ricardo

[Annie_he]

Hi Ricardo,

    We are using 32MHZ crytal from TXC, load capcitor is 8pF in the datasheet, which is the same as NDK NX1612SA (EXS00A-CS14160) that NXP recommended. That would be ok?

    So we hope to discuss with you the viability of changing Xtaltrim to get more ideal Frequency accuracy and how to do?

    Best Regards,

    Annie

[Ricardo_Zamora · Accepted solution]

Hi Annie,

It would depend on the XTAL you are using. For example, it has to be compliant with the +/-50ppm.

But, for your question about the trim, you could use the PLATFORM_SetXtal32MhzTrim.

You could take as a base the ShellCalibration_SetXtal32MHzTrim from the ble_shell example.

Hope this helps.

Regards,

Ricardo