Crystal Oscillator

RE: Crystal Oscillator

ps_anu — Tue, 18 Dec 2018 08:33:27 GMT

i want to run the timer for one minute ..after the completion of one minute it should read the data ..

how to do that?

RE: Crystal Oscillator

Sunil vignesh — Mon, 26 Nov 2018 06:40:04 GMT

thank you bjorn

RE: Crystal Oscillator

bjorn-spockeli — Fri, 23 Nov 2018 09:38:11 GMT

Yes, the nRF52832 will turn on the 32MHz oscillator when its requested by peripheral(s) and turn it off when the periheral(s) no longer need it.

RE: Crystal Oscillator

Sunil vignesh — Fri, 23 Nov 2018 08:52:41 GMT

Thank you Bjorn, I will use this

if i use 32Mhz external crystal oscillator also. power management will take care about the low power mode.

RE: Crystal Oscillator

bjorn-spockeli — Fri, 23 Nov 2018 07:37:52 GMT

Hi Sunil,

the clock sources are automatically managed on the nRF52832, i.e. the peripherals will enable/disable the required clock source. However, some peripherals require the 32MHz clock, e.g. the SAADC, TIMER, Serial Interfaces etc

The same goes for power management, it is automatically managed by the nRF52832, i.e power is routed to the peripheral if its enabled/initialized and cut if it is disabled/uninitialized. So whenever you're not using a peripheral it is important that you uninitialized said peripheral.

I recommend that you use the Timer library, which uses the RTC1 peripheral, which in turn uses the 32kHz oscillator which has a very low run current, 0.6uA if the LFRC is used and 0.25uA if an external 32kHz oscillator is used.

It is also possible to use the SAADC in low power mode by setting the .low_power field in the nrfx_saadc_config_t struct passed to nrfx_saadc_init.

NOte: The external 32kHz is optional as the nrf52832 can use the internal 32kHz RC oscillator, but the 32MHz oscillator is mandatory for using the RADIO as a Bluetooth Radio.

Best regards

Bjørn