Using RTC to control the real timestamp

RE: Using RTC to control the real timestamp

ovrebekk — Tue, 01 Sep 2020 09:26:17 GMT

Awesome Adeel, I will close the case then 🙂

RE: Using RTC to control the real timestamp

Adeel — Mon, 31 Aug 2020 13:54:03 GMT

Hi Tobjorn,

Thanks for the help on this 🙂. Solved my issue of getting the time through NTP:

Regards,

Adeel.

RE: Using RTC to control the real timestamp

ovrebekk — Mon, 31 Aug 2020 07:56:04 GMT

Hi Adeel

You could do something like this, using the time.h library similar to how it's done in the calendar example:

// Convert to string using time.h
time_t time = unix_time_ms / 1000;
struct tm local_time;
local_time = *localtime(&time);
char time_string[80];
strftime(time_string, 80, "%x - %H:%M:%S", &local_time);
printk("Local time from time.h: %s\n", time_string);

The main difference is that you need to divide the timestamp by 1000, since the time.h library expects a second based time value.

In order to use time.h you also need to enable one of the standard C libraries, which can be done by adding the following line to prj.conf:

CONFIG_NEWLIB_LIBC=y

Best regards
Torbjørn

RE: Using RTC to control the real timestamp

Adeel — Fri, 28 Aug 2020 15:42:43 GMT

Hi Tobjorn,

Thanks, I was able to run the example file you sent and it works. Thanks for the effort.

I just wanted to know one last thing. How would you suggest to go about and convert the time I am getting into a date_time format as we use normally. Any such available library or struct I could use.

Really appreciate the help on this 🙂.

RE: Using RTC to control the real timestamp

ovrebekk — Fri, 28 Aug 2020 14:29:53 GMT

Hi Adeel

I messed around with it today, and finally got it to work with some help from the developer.

You can find my example here:
https://github.com/too1/mqtt_w_date_time

It is based on the mqtt_simple example, but I moved all the mqtt functions into a separate file for clarity, and added the date_time calls into main.

Some things worth noting:

1) To make date_time.c build I had to make a small change to the code. I explain this in the readme of the repository.

According to the developer this issue is fixed in the master branch, but was not properly tested in the v1.3.0 tag.

2) In order to get the time information properly he suggested I set CONFIG_DATE_TIME_MODEM=n in the project configuration (prj.conf). This prevents the library from trying to get the time from the modem, and instead accesses the NTP server.

3) He also suggested adding some delay between the first call to date_time_update() and date_time_now(), as you can see in my example.

With these things in place I am able to see the current time printed after the program has run for a bit:

Best regards
Torbjørn

RE: Using RTC to control the real timestamp

Adeel — Thu, 27 Aug 2020 15:04:26 GMT

Hi Tobjorn,

I appreciate your support. You can get back to me tomorrow, no issues :).

RE: Using RTC to control the real timestamp

ovrebekk — Thu, 27 Aug 2020 14:59:58 GMT

Hi Adeel

Sorry for the slow response. To be honest I haven't handled much nRF91 support up until now, and have spent some time just to get the tools and basic examples running.

I will do my best to integrate your changes and get back to you by tomorrow.

Best regards
Torbjørn

RE: Using RTC to control the real timestamp

Adeel — Tue, 25 Aug 2020 08:41:45 GMT

Hi Torbjorn,

I am attaching my main file for you to have a look. I have added the date_time_update() ; time_modem_get() and date_time_now() functions in the main loop part of the code. I am just trying to build up on the asset tracker application using the date_time library.

You can try it out and let me know if it works or you can modify it as well :).

Regards,

Adeel.

devzone.nordicsemi.com/.../43000.main.c

RE: Using RTC to control the real timestamp

ovrebekk — Tue, 25 Aug 2020 07:48:49 GMT

Hi Adeel

One of my colleagues made an example for NTP that he made available online, but I am not sure the date_time library is used, so I don't know how relevant it is for you:
https://github.com/Rallare/fw-nrfconnect-nrf/tree/nrf9160_samples/samples/nrf9160/ntp

Are you able to share your code with me?
Then I will give it a go and see if I can get it to work on my end.

Best regards
Torbjørn

RE: Using RTC to control the real timestamp

Adeel — Mon, 24 Aug 2020 14:22:33 GMT

This is the output coming up on the screen. I even tried different NTP servers to try and get the error out.

Regards,

Adeel.

RE: Using RTC to control the real timestamp

Adeel — Mon, 24 Aug 2020 11:31:34 GMT

Hi Tobjorn,

Unfortunately yes, its still reporting the same error. The CEREG value says the modem is connected but the error still remains. Is there any way or other example where this could have been implemented for a reference ?

Regards,

Adeel.

RE: Using RTC to control the real timestamp

ovrebekk — Mon, 24 Aug 2020 11:07:38 GMT

Hi Adeel

After turning the modem back on it will take some time for it to reconnect to the network.

If you wait for the CEREG notification informing you that the modem is connected is the date_time library still reporting errors?

Best regards
Torbjørn

RE: Using RTC to control the real timestamp

Adeel — Fri, 21 Aug 2020 07:50:16 GMT

Hi Tobjorn,

Yes, I was trying to turn off my modem for a certain time and then turn it back on later. Even when it is turned back on (AT+CFUN = 1), I still get the same error.

2020-08-20T11:13:36.441Z DEBUG modem << AT send: AT+CFUN=1
2020-08-20T11:13:36.546Z DEBUG modem << AT ret: OK
2020-08-20T11:13:37.283Z DEBUG modem << [00:01:05.495,147] [1;31m<err> date_time: sntp_query, error: -1[0m
2020-08-20T11:13:37.294Z DEBUG modem << [00:01:05.503,540] [1;31m<err> date_time: getaddrinfo, error: -11[0m
2020-08-20T11:13:37.302Z DEBUG modem << [00:01:05.513,458] [1;31m<err> date_time: getaddrinfo, error: -11[0m
2020-08-20T11:13:37.312Z DEBUG modem << [00:01:05.522,064] [1;31m<err> date_time: getaddrinfo, error: -11[0m
2020-08-20T11:13:37.319Z DEBUG modem << [00:01:05.530,700] [1;31m<err> date_time: getaddrinfo, error: -11[0m
2020-08-20T11:13:37.329Z DEBUG modem << [00:01:05.538,482] [1;31m<err> date_time: Not getting time from any NTP server[0m

Is there any procedure or a way to use the date_time library. Is there any specific example to use that library ?

RE: Using RTC to control the real timestamp

ovrebekk — Fri, 21 Aug 2020 07:33:58 GMT

Hi Adeel

Looking at the log it appears you are disabling the modem before this issue occurs:

2020-08-20T11:13:04.559Z DEBUG modem << AT send: AT+CFUN=0

Can you confirm whether or not this was intentional?

After disabling the modem you can see that you get detached, and at this point the data connection is lost.

Best regards
Torbjørn

RE: Using RTC to control the real timestamp

Adeel — Thu, 20 Aug 2020 11:32:09 GMT

Hi Torbjorn,

I am trying to use the date_time.h library that incorporates SNTP in it. When i try to run it, I get the following errors that I am unable to solve.

devzone.nordicsemi.com/.../2020_2D00_08_2D00_20T11_5F00_12_5F00_42.702Z_2D00_log.txt

Could you let me know the methods to solve this error that I am getting. This is using the date_time.h library.

Regards,

Adeel.

RE: Using RTC to control the real timestamp

ovrebekk — Thu, 20 Aug 2020 11:22:51 GMT

Hi Adeel

My bad, I thought you were using an nRF52 series device.

I don't have a lot of experience with the nRF9160, but I got a tip from a colleague that the SNTP library might provide what you need:

https://docs.zephyrproject.org/latest/reference/networking/sntp.html

Best regards
Torbjørn

RE: Using RTC to control the real timestamp

Adeel — Wed, 19 Aug 2020 12:29:24 GMT

Hi Torbjorn,

Is there any possibility of an example for nRF9160DK. I am using NCS v1.3.0 nRF Connect for desktop and running the asset tracker application.

I tried using the date_time.h library to try and get the time either using NTP or through MODEM. I can use the AT+CCLK command to fix the time manually and then read it but I would like the network to get the current time for me.

Regards,

Adeel.

RE: Using RTC to control the real timestamp

ovrebekk — Wed, 19 Aug 2020 12:23:57 GMT

Hi Adeel

You might want to have a look at the calendar example on our Github account:
https://github.com/NordicPlayground/nrf5-calendar-example

It basically uses the standard time.h library in C to decode rolling second counter into seconds, minutes, hours, days etc, and uses the RTC timer in the nRF52 to update the time every second.

Please be aware that if you need to keep track of time over long periods you should use an external 32k crystal for the best accuracy.

Best regards
Torbjørn