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

[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.

[Jones_swDev]

Ok I changed all above as you mentioned. I did not get any Repsonse from the RTC.

static void rtc_handler(nrfx_rtc_int_type_t int_type) {
	LOG_INF("%s","Intr");
   	set_intr_src(0x05);
}

static void rtc_config(void) { 
	const nrfx_rtc_t rtc = NRFX_RTC_INSTANCE(RTC_INSTANCE_NUMBER);
	uint32_t err_code;
	//Initialize RTC instance
	nrfx_rtc_config_t rtc_config;
	rtc_config.prescaler = RTC_FREQ_TO_PRESCALER(10);
	err_code = nrfx_rtc_init(&rtc, &rtc_config, rtc_handler);
	LOG_INF("ErrorCode: %d",err_code);
	err_code = nrfx_rtc_cc_set(&rtc,0,100,true);
	LOG_INF("ErrorCode: %d",err_code);
	//Power on RTC instance
	nrfx_rtc_enable(&rtc);
}

Is this code OK so far? I set the prescaler to 10 Hz and ah the cc to 100 so in my world it should trigger every 10 Sek. and should then print out the log message from rtc_handler()

The return-statments from the rtc configuration are both ok


Any Idea?