KW45 crystal oscillator parameter matching settings

[Taiyi]

Hello !

        Now I am debugging the KW45 PCBA circuit board, crystal vibration needs to be matched to make the vibration waveform more stable, and parameters need to be modified from the perspective of hardware and software design. How do I adjust the software and hardware?

        Very much looking forward to receiving a reply and giving some suggestions.

[Christine_Li]

Hi, @Taiyi 

For the  crystal oscillator, you can refer to our KW45 Product Family Data Sheet  for reference.

Especially the part: 3.2.1 Reference oscillator specification

Table 31  shows typical specifications for the Crystal Oscillator. 

Table 32 shows 32 kHz oscillator electrical specifications.

After read this part, if you still have any other queries, please feel free to contact me again.

Best regards,

Christine.

[Taiyi]

Hi !

     Now we are using an external 32MHZ crystal oscillator, but the capacitor matching this crystal oscillator is integrated inside the KW45 chip. Please help us to tell how to configure the crystal oscillator matching capacitor inside the chip.

[Christine_Li]

Hi， @Taiyi 

For 32MHZ crystal oscillator,  you can refer to 3.2.1 Reference oscillator specification which is 32MHz.

Best regards,

Christine.

[Taiyi]

Hi,

         As we all know, all crystal oscillators need two external capacitors to work properly, and KW45 currently has two capacitors integrated inside the chip. At present, the matching capacitor of the crystal oscillator of the Bluetooth chip on the market is integrated inside the chip, and the current specification is not written above. The picture is TI's application notes. I would like to know if KW45 has a similar adjustment interface that can modify the internal capacitance parameters. The KW45 is relatively new and may not have been released yet.

[Christine_Li]

Hi, @Taiyi 

Until now, I didn't find any interface that can adjust these two capacitors.

Best regards,

Christine.

[Christine_Li]

Hi, @Taiyi 

For 32 KHz Clock Control Module (CCM32K) ,I fond that CL can be adjusted according to our KW45 reference manual

in section 27.6.1.4 32 kHz OSC Control Register (OSC32K_CTRL) on page 731. It mentions that 15-12 XTAL_CAP_SEL. And also it has calculation formula.

So, you can reference this part.

Hope above info is helpful for you.

Best regards,

Christine.

[Taiyi]

Hi,

 I found this description in this document <<KW45B41Z-EVKUM>> Page29, saying that the frequency can be adjusted, but I did not find a configurable register in the <<KW45RM>> manual, where can I adjust it?

[Christine_Li]

Hi, @Taiyi 

This thread has been closed for more than 1 month. The related SF case could not be reopen again.

Please help to create a new thread to discuss further. Then it will create a related SF case.

Sorry for the inconvenience.

Best regards,

Christine.

[Taiyi]

Hello!