nrf52840 RCT2 configuration and usage

[Egor Dolgalev]

Hello,

I'm trying to enable RTC2 for nrf52840 DK to use as a date time clock and set/get over SMP protocol. RTC0 is used for MPSL, RTC1 is used by the system.

I configured MCU MGR option:

CONFIG_MCUMGR_GRP_OS_DATETIME=y

I configured RTC:

CONFIG_COUNTER=y
CONFIG_NRFX_RTC2=y
CONFIG_RTC=y

DTS for RTC2:

aliases {
		rtc = &rtc2;
	};
	
&rtc2 {
    status = "okay";
};

The command to set date-time works and return empty result. But when try to get date-time I see strange result. For instance:

{
  "datetime": "39997-165-36T05:168:00"
}

And now matter how many times I get it I see the same.

For me it looks like the RTC2 is not initialized. But i check it readiness in main:

if (!device_is_ready(rtc)) {
		printk("Device RTC is not ready\n");
		return 0;
	}

 

Anything I forget to do to use RTC2 as a date-time source?

[narangmayank]

Hi Egor Dolgalev 

I'm able to set/get epoch time on nRF52840 via RTC2. Can you share more information on your rtc set/get implementation. Are you directly using nrfx library?

Best Regards,

Mayank

[Egor Dolgalev]

I don't use nrfx library directly. I use MCU manager over SMP protocol with the next command https://docs.zephyrproject.org/latest/services/device_mgmt/smp_groups/smp_group_0.html#date-time-command

To send this command over UART I use AuTherm application from this https://docs.zephyrproject.org/latest/services/device_mgmt/mcumgr.html#tools-libraries

[Simonr]

Hi

Just to check, are you using the os_mgmt_datetime sample in <ncs version>\zephyr\tests\subsys\mgmt\mcumgr\os_mgmt_datetime for this? Where does this strange output print from exactly? Are you sure you have set the date time as reference somewhere in your project so the RTC has a reference point? 

Can you show me the full log of your application running so we can get a better understanding of what exactly is returning this value?

Best regards,

Simon

[Egor Dolgalev]

Hi Simonr,

In my original project I don't use this example. But I adopted the test you mentioned to reproduce this issue. I attached my project. I did a build for nrf52840dk board with RTC0 used and SDK 3.0.0 version. To test date-time set/get functionality I use AuTerm tool and analyzed the terminal traffic to see what is inside the packets.

I did next command sequence:

1. Get current time

2. Set current time

3. Get current time

The traffic looks like the next:

\06	AAsIAAABAAANBKBXIA==
\06	ACkJAAAfAAANBL9oZGF0ZXRpbWVzMjk0OC0wMS0wMFQwMDo0NTowMP88ig==

\06	AC8KAAAlAAAOBKFoZGF0ZXRpbWV4GTIwMjUtMDUtMjBUMTQ6NTU6MTYrMDI6MDDQUw==
\06	AAwLAAACAAAOBL//9T4=

\06	AAsIAAABAAAPBKA5QA==
\06	ACkJAAAfAAAPBL9oZGF0ZXRpbWVzMjk0OC0wMS0wMFQwMDo0NTowMP83Ew==

This is a Base64 packets and I decrypted them based on the SPM protocol specification and UART transport specification:

Get
\06	AAsIAAABAAANBKBXIA==
000b 0800000100000d04 a0 5720
{}
\06	ACkJAAAfAAANBL9oZGF0ZXRpbWVzMjk0OC0wMS0wMFQwMDo0NTowMP88ig==
0029 0900001f00000d04 bf686461746574696d6573323934382d30312d30305430303a34353a3030ff 3c8a
{ "datetime": "2948-01-00T00:45:00"}

Set
\06	AC8KAAAlAAAOBKFoZGF0ZXRpbWV4GTIwMjUtMDUtMjBUMTQ6NTU6MTYrMDI6MDDQUw==
002f 0a00002500000e04 a1686461746574696d657819323032352d30352d32305431343a35353a31362b30323a3030 d053
{"datetime": "2025-05-20T14:55:16+02:00"}
\06	AAwLAAACAAAOBL//9T4=
000c 0b00000200000e04 bfff f53e
{}

Get
\06	AAsIAAABAAAPBKA5QA==
000b 0800000100000f04 a0 3940
{}
\06	ACkJAAAfAAAPBL9oZGF0ZXRpbWVzMjk0OC0wMS0wMFQwMDo0NTowMP83Ew==
0029 0900001f00000f04 bf686461746574696d6573323934382d30312d30305430303a34353a3030ff 3713
{_ "datetime": "2948-01-00T00:45:00"}

As you can see even if I set the proper date-time in the second command with positive response to this command

{"datetime": "2025-05-20T14:55:16+02:00"}

I can't get the proper date-time on the following read. What interesting this output is the same as a first read and doesn't change

{ "datetime": "2948-01-00T00:45:00"}

os_mgmt_datetime.zip

[Susheel Nuguru]

Hi Egor, 

I wanted to try to pitch in my 2 cents here.

I am suspecting that this is because you have not enabled the counter API

Enable this in your prj,conf using RTC2 just to be sure since rtc0 is used by RTOS. 

CONFIG_COUNTER=y                    
CONFIG_RTC=y  
CONFIG_NRFX_RTC2=y  

also set this your overlay instead of rtc0

aliases {
    rtc = &rtc2;
};

&rtc2 {
    status = "okay";
};

I have not tried your sample but if this does not work, then i will try to debug your app on why you have simple date and time feature not working.