nrf51822 rtc with softdevice

RE: nrf51822 rtc with softdevice

vernon — Thu, 28 Dec 2017 10:48:14 GMT

Hi Martin,

Thank you very much for your reply, I will use a app_timer to fulfill the rtc function.

RE: nrf51822 rtc with softdevice

MartinBL — Thu, 28 Dec 2017 10:42:25 GMT

Hi Vernon. The nRF51 only has two RTCs. The nRF52832 and nRF52840 have 3 RTCs.

In your case it should be possible to use the RTC driver in the SDK, but if you want to use RTC1 in your own way you cannot use the app_timer library at the same time. Have a look at the RTC example in the SDK. If you use a Softdevice, then make sure to use instance 1 of the RTC with:

const nrf_drv_rtc_t rtc = NRF_DRV_RTC_INSTANCE(1); /**< Declaring an instance of nrf_drv_rtc for RTC1. */

RE: nrf51822 rtc with softdevice

vernon — Thu, 28 Dec 2017 06:22:03 GMT

Hello Ole Saeher, thanks a lot for your answer, I have found that nrf51822 just has RTC0 and RTC1 defined in C:\Keil_v5\ARM\PACK\NordicSemiconductor\nRF_DeviceFamilyPack\8.11.1\Device\Include\nrf51822_peripherals.h, RTC0 is used by the SoftDevice, and RTC1 by the app_timer library, so nrf51822 don't support RTC2? If I want to achieved a calendar, is it only app_timer could help to achieved that without an external RTC chip?

RE: nrf51822 rtc with softdevice

Ole Saether — Wed, 27 Dec 2017 12:37:39 GMT

Check the file counter.c in the example project ble_central_and_peripheral\experimental\ble_app_att_mtu_throughputin nRF5_SDK_12.2 on how to configure and use RTC2.