Modify clock in gazell on nRF51822

[yjpark]

Hello, sirs.

My question is how to configure clock in gazell protocol on nRF51822

I look at the example gzp_dynamic_pairing but that does not have a code part of modifying clock.

I know defining SystemCoreClock on "system_nrf51.c" and i don't know effecting on other operating.

thank you, developers.

(i'm so sorry for my poor english skill. TT)

[Ole Morten]

The only clock source Gazell needs is an external high frequency crystal. If you use a 16 MHz crystal, no configuration is neither possible nor necessary. If you use a 32 MHz crystal, you should follow the procedure described in the PAN to make everything work correctly.

[yjpark]

@ole morten

Thank you. but i have one more question, additionally. Should i use a 16/32MHz external crystal for RF( including gazell) communication on nRF51822? I operate a ble communication on nrf51822 EK, set the clock NRF_CLOCK_LFCLKSRC_SYNTH_250_PPM( our provider tells it is internal clock source ). I think RF cannot set clock in that way. is it right?

Regards

• yjpark

[Ole Morten]

You have to separate between the high frequency clock, which requires an external either 16 MHz or 32 MHz crystal, and the low frequency clock which can either use an external 32.768 kHz crystal, an internal 32.768 kHz RC or synthesize the clock from the 16 MHz.

Gazell only uses the high frequency clock, so the low frequency clock settings are not applicable for it.

For BLE, the option you have quoted here synthesize the low frequency clock from the 16 MHz, and this is not recommended. You should rather use the RC, since that has been tested better and gives a lot lower current consumption.

[yjpark]

@Ole Morten

Oh, i understand. Thank you for your help.

• yjpark