High frequency clock request.

[mjm46]

Is it possible to modify the software in such a way that the nRF1822 sets a GPIO high when it requires its high frequency clock?

We would like to avoid using an extra XTAL in our design, but don't want to leave the clock generator running when it is not needed due to power constraints.

Thanks in advance!

[Asbjørn]

Various peripherals in the chip requires the external 16 MHz to be running, but you could essentially add an extra line of code for the init/start calls for each of those peripherals. So that every time a peripheral needs 16XOSC a GPIO goes high. Have a look in chapter 8.3 of the nRF51822 product specification for details on which peripheral requires external 16 MHz.