RTC timer

cptel

I am able to set RTC time using

// Ignore the values as they are for test purpose only
struct rtc_time sRtcTime;
sRtcTime.tm_year = 2030;
sRtcTime.tm_mon = 2;
sRtcTime.tm_mday = 10;
sRtcTime.tm_hour = 22;
sRtcTime.tm_min = 48;
sRtcTime.tm_sec = 20;
rtc_set_time(rtc_dev, &sRtcTime);

print of above dataset value:
[00:00:02.462,066] <inf> PWL: 22:48:20 3/10/3930 - 253069
However get RTC time

	struct rtc_time time;
	rtc_get_time(rtc_dev, time);

give me garbage

[00:00:07.970,794] <inf> PWL: Get Time
[00:00:07.975,006] <inf> PWL: 0:0:975720936 536983993/101255/203815 - 7959

i’ve added the following in my circuitdojo_feather_nrf9151_ns.overlay file:

&rtc0 {
    status = "okay";
    prescaler = <127>;
};

and updated the prj.conf file with:

# RTC
CONFIG_COUNTER=y
CONFIG_RTC=y
CONFIG_RTC_ALARM=y
CONFIG_RTC_UPDATE=y

Where did I go wrong…..

cptel

Also, can the RTC wakeup the PMIC/Feather if it was in hibernate or ship mode?

jaredwolff

@cptel I have not played with the internal nRF9151 RTC. I usually use the higher level time keeping API. (Not sure if it’s used there either)

Also, can the RTC wakeup the PMIC/Feather if it was in hibernate or ship mode?

No, the ship model is provided by the PMIC. Everything except for the PMIC is powered down in ship mode.

cptel

jaredwolff how does the module wake up from ship mode? RESET button on the board?

jaredwolff

cptel jaredwolff how does the module wake up from ship mode? RESET button on the board?

Steps to Wake the nPM1300 from Ship ModePress the SHPHLD (Ship/Hibernate Hold) Button:

Pull the EN pin down for the configured time. Or..

Connect a USB Cable:

Attach a USB cable to the designated USB port. This detects VBUS presence and automatically exits Ship mode

cptel

which higher level API do you use for time keeping?

jaredwolff

#include <date_time.h>

uint64_t ts = 0;

/* Get the timestamp */
err = date_time_now(&ts);
if (err)
{
    LOG_ERR("Unable to get timestamp. (err: %d)", err);
    break;
}

cptel

jaredwolff I already use date_time_now() function - though my assumption was that its only available with cell connection. I’ll look more into it. I was looking to use something that kept track of time even when the module was in low power mode.

jaredwolff

There is no “always on” RTC on the nRF9151 Feather. Sorry! I’ve found that as long as you have cell signal the time get’s fetched on connect reliably.

cptel

It would a good useful feature for future revisions - thx!

cptel

update… after doing further research, RTC in nRF9151 stands for: Real Time Counter and not Real Time Clock. The date_time_now() is best way to get time/date information.