main clock control

[hjjeon]

Dear nordic guy, I'm developing with nrf51822. I have one question regarding main clock control. I want to turn on and off 16Mhz clock in application side. application side use the rtc clock for timer. and I want to turn off when device goes to the non-advertising state for power saving. Could you explain how to turn on and off the 16mhz clock? I want to know function header name.

[Ole Morten]

Unless you specifically request the HFCLK to be running (for example using sd_clock_hfclk_request()), the 16 MHz clock will be turned off whenever possible. Take a look at this question for information on how this works.

In summary, you should make sure to disable all peripherals whenever they're not actually needed.

[hjjeon]

Dear Morten,thank for your reply,I have one question. Do I have to disable gpio and uart close and spi close? our device use the uart,spi,gpio. If so, how can I take gpio signal? gpio pin is used user detect pin.

[Ole Morten]

You can see in section 8.3 which modules of the nRF51 uses which clock and regulator sources. For GPIO, if you want to wake up the chip with a low current consumption, you should use the PORT event. You can take a look at this repository for examples of it: https://github.com/NordicSemiconductor/nrf51-powerdown-examples Also this question may be useful: https://devzone.nordicsemi.com/index.php/is-it-possible-to-create-a-gpio-button-interrupt-without-gpiote