RE: How to config NRF51822 custom board Xtal Freq to 32MHz using nrf51dk

Jake Jung — Sun, 18 Feb 2018 04:26:11 GMT

Thang you Berg, It worked. I was keep writing the NRF -> XTALFREQ code before the main loop. It worked well after I put the code inside the main loop.

Thanks a lot!!

RE: How to config NRF51822 custom board Xtal Freq to 32MHz using nrf51dk

Vidar Berg — Fri, 16 Feb 2018 09:04:18 GMT

Hi,

Is not important when you update the frequency setting as long as it done before the crystal is started by the app. You can update the register in main so that you don't have to modify the startup files:

int main(void)
{
    // Set the external high frequency clock source to 32 MHz
    NRF_CLOCK->XTALFREQ = 0xFFFFFF00;
 ...
}

The other option is to change the reset value of NRF_CLOCK->XTALFREQ to 32 MHz. Reset value is defined by NRF_UICR->XTALFREQ