Where to get "nrfx_rtc_t const *p_instance" for nrfx_rtc_init()

[Jones_swDev]

I could not find a way, where I can get the nrfx_rtc_t const *p_instance for the nrfx_rtc_init function. There is no example where it is shown where to get this struct from.

[Jørgen Holmefjord]

Hi,

The nrfx_rtc_t must be defined in your application. This is normally done like this:

#define RTC_INSTANCE_NUMBER 0

const nrfx_rtc_t rtc = NRFX_RTC_INSTANCE(RTC_INSTANCE_NUMBER);

Where RTC_INSTANCE_NUMBER represents the RTC instance you want to use (in this case RTC0).

You can then pass this instance to nrfx_rtc_init() like this:

nrfx_rtc_init(&rtc, .., ..);

This is shown in the RTC peripheral example in nRF5 SDK (with nrf_drv_rtc APIs, but this is a simple replacement to nrfx).

Best regards,
Jørgen

[Jones_swDev]

Thanks for your reply.
I think it will work, but the compiler tells me it is missing NRFX_RTC0_INST_IDX. I think, i have to activate the rtc0 in a config file. Can you tell me where?

Best regards
Jones

[Jørgen Holmefjord]

Yes, that is correct. You need to enable the RTC instance in your sdk_config.h file (given that you are using nRF5 SDK and not nRF Connect SDK):

// <e> NRFX_RTC_ENABLED - nrfx_rtc - RTC peripheral driver
//==========================================================
#ifndef NRFX_RTC_ENABLED
#define NRFX_RTC_ENABLED 1
#endif
// <q> NRFX_RTC0_ENABLED  - Enable RTC0 instance
 

#ifndef NRFX_RTC0_ENABLED
#define NRFX_RTC0_ENABLED 1
#endif

Make sure that you comment out or completely remove any legacy configs for the driver in the sdk_config.h file, as these will overload the nrfx configs in the file apply_old_config.h if defined, regardless of their defined value.

// <e> RTC_ENABLED - nrf_drv_rtc - RTC peripheral driver - legacy layer
//==========================================================
// #ifndef RTC_ENABLED
// #define RTC_ENABLED 1
// #endif

// <q> RTC0_ENABLED  - Enable RTC0 instance
 
// #ifndef RTC0_ENABLED
// #define RTC0_ENABLED 1
// #endif

[Jones_swDev]

Ah sorry, my fault. I forgot to meantion, that I am currently using the nrf Connect SDK v 2.1.0.

[Jørgen Holmefjord]

Then you need to set CONFIG_NRFX_RTC0=y.