How to schedule events and tasks at particular time intervals

RE: How to schedule events and tasks at particular time intervals

Carl Richard — Fri, 30 Apr 2021 11:22:15 GMT

No problem! And that makes sense.

Best regards,
Carl Richard

RE: How to schedule events and tasks at particular time intervals

Adeel — Fri, 30 Apr 2021 11:21:21 GMT

Hi Carl,

Thanks. This explains why I was also getting the getaddrinfo error. Thanks for the explanation.

Regards,

Adeel.

RE: How to schedule events and tasks at particular time intervals

Carl Richard — Fri, 30 Apr 2021 08:04:30 GMT

Hello!

Great! PCO stands for Protocol Configuration Options and is used for transferring various information relevant for the connection, for example DNS. The NB-IoT spec requires ePCO, but some networks still only supports regular PCO which is why this option is available. There is some more information in this thread. It should not affect your application in any way!

Best regards,
Carl Richard

RE: How to schedule events and tasks at particular time intervals

Adeel — Thu, 29 Apr 2021 10:27:26 GMT

Hi Carl,

Yes I was getting the NB-IoT connection.

I was able to get past the error using : CONFIG_LTE_LEGACY_PCO_MODE=y

I wanted to understand what is the NB-IoT PCO mode and how is it different from the normal NB-IoT ?

Regards,

Adeel.

RE: How to schedule events and tasks at particular time intervals

Carl Richard — Wed, 28 Apr 2021 13:48:22 GMT

Hello again, Adeel!

Are you certain that the device manages to get a connection? When changing between NB-IoT and LTE-M you need to make sure that you SIM supports both, or change to another SIM.

Secondly, when changing the project configuration I suggest that you follow the steps described in the "Configuring your application"-documentation. Namely, changing the prj.conf or using the configuration tool in SES. By changing autoconf.h directly there may be some dependencies of the configuration that are lost.

Best regards,
Carl Richard

RE: How to schedule events and tasks at particular time intervals

Adeel — Wed, 28 Apr 2021 10:47:56 GMT

Hi Carl,

I just had another question to ask regarding the above thread.

I am having a pretty poor reception using : CONFIG_LTE_NETWORK_MODE_LTE_M 1

So, I tried to change to NB-IoT using : CONFIG_LTE_NETWORK_MODE_NBIOT to improve my RSRP.

I did it through the autoconf.h file.

The NB-IoT is configured properly as well and I can see it when I do :

AT%XSYSTEMMODE?

%XSYSTEMMODE: 0,1,0,0

OK

This helps me understand that I have configured for NB-IoT.

I try to run my application with NB-IoT config but I see that the date_time handler does not give me the right time.

It works perfectly with the : CONFIG_LTE_NETWORK_MODE_LTE_M

Do I need to do anything else in order to set up my device with NB-IoT config ?

P:S : I am in Germany and NB-Iot works well here.

Regards,

Adeel.

RE: How to schedule events and tasks at particular time intervals

Adeel — Thu, 08 Apr 2021 08:52:50 GMT

Hi Carl,

Thanks for this lead. Got it working by using the blocking semaphore 🙂.

Regards,

Adeel.

RE: How to schedule events and tasks at particular time intervals

Carl Richard — Wed, 07 Apr 2021 14:10:45 GMT

Hi, Adeel!

You're getting an error when calling date_time_now that indicates that a valid time aren't available yet. Instead of busy_wait I suggest that you use a blocking semaphore that is released by a handler for date_time_update_async callbacks. This way you can ensure that a valid time is available when calling date_time_now.

You can how I have done this here.

Best regards,
Carl Richard

RE: How to schedule events and tasks at particular time intervals

Adeel — Wed, 07 Apr 2021 10:06:22 GMT

Hi Carl,

I had a question regarding this ticket. The above code that you sent worked perfectly for NCS v1.3.0 .

I did this in NCS v1.3.0 and this works perfectly.

	modem_configure();  //to get LTE connection

    date_time_update(); //To get current time

    printk("Busy-wait %u s\n", BUSY_WAIT_S);
    k_busy_wait(BUSY_WAIT_S * USEC_PER_SEC);  //2 seconds delay

    int64_t curr_time;     //above code
    date_time_now(&curr_time);

    int64_t curr_time_s = curr_time / 1000;            //Convert to seconds
    struct tm *readable_time = gmtime(&(curr_time_s)); //Get human readable time with time.h
    printk("Curr min: %d\n", readable_time->tm_min);
    printk("Curr sec: %d\n", readable_time->tm_sec);

    int32_t delay = 3600 - (readable_time->tm_min) * 60 - readable_time->tm_sec;
    int32_t real_time = delay + 600;
    printk("Delay is: %d\n", delay);
    printk("Real Delay is: %d\n", real_time);

The above output is correct.

But when I try to do the same in NCS v1.4.2 or NCS v1.5.0, it doesn't work the way I want it to.

	modem_configure(); //for LTE connection

    date_time_update_async(NULL);  //to get current time

    printk("Busy-wait %u s\n", BUSY_WAIT_S);
    k_busy_wait(BUSY_WAIT_S * USEC_PER_SEC);  //2 seconds delay

    int64_t curr_time;   //above code
    date_time_now(&curr_time);

    int64_t curr_time_s = curr_time / 1000;            //Convert to seconds
    struct tm *readable_time = gmtime(&(curr_time_s)); //Get human readable time with time.h
    printk("Curr min: %d\n", readable_time->tm_min);
    printk("Curr sec: %d\n", readable_time->tm_sec);

    int32_t delay = 3600 - (readable_time->tm_min) * 60 - readable_time->tm_sec;
    int32_t real_time = delay + 300;
    printk("Delay is: %d\n", delay);
    printk("Real Delay is: %d\n", real_time);

The only change is using : date_time_update_async(NULL) as date_time_update() is not supported in higher NCS versions.

I get the following in NCS v1.5.0 :

This output is incorrect (the Curr min and Curr sec are wrong).

Could you try to reproduce this in NCS v1.5.0 and verify ?

Regards,

Adeel.

RE: How to schedule events and tasks at particular time intervals

Adeel — Mon, 25 Jan 2021 17:20:15 GMT

Hi Carl,

Yes, I understood the logic of calculating the delay and this is what I needed.

Thanks a lot, got it working at my end through the delayed work queue :).

Regards,

Adeel.

RE: How to schedule events and tasks at particular time intervals

Carl Richard — Fri, 22 Jan 2021 11:04:54 GMT

Hi, Adeel!

I suggest that you do the following procedure:
1. Start up, connect and get current time
2. Submit a delayed work item as described in the documentation. You can calculate the delay by converting to human readable time (see the attached code) and calculating how much time is left to, for example, the next whole hour.
3. You can then avoid doing this again by starting a timer with the work item that makes the device transmit at the desired interval afterwards. Note that it may drift over time, so you should calibrate after a certain amount of uploads.

Delay calculation code below:

//Get timestamp
int64_t curr_time;
date_time_now(&curr_time);

int64_t curr_time_s = curr_time/1000;   			//Convert to seconds
struct tm * readable_time = gmtime(&(curr_time_s)); //Get human readable time with time.h
LOG_INF("Curr min: %d", readable_time->tm_min);
LOG_INF("Curr sec: %d", readable_time->tm_sec);

int delay = 3600-(readable_time->tm_min)*60 - readable_time->tm_sec;

This requires the time.h library. I hope it makes sense!

Best regards,
Carl Richard

RE: How to schedule events and tasks at particular time intervals

Adeel — Thu, 21 Jan 2021 16:20:45 GMT

Hi Carl,

I am using the date_time library to get the real time using the NTP server.

Can you let me know how can I use this time to synchronize my next intervals.

For example, my sample starts at 17:02:09 and I want my next interval of sending data over MQTT to occur at 18:00:00.

For some reason, even if my application sample starts at 17:25:34 , still I want it to send the first data at 18:00:00 .

Once I send the data for the first time, then I understand that the kernel timers can schedule it as per our timer allotment.

How can I schedule events like this because the kernel timers are defined for fixed intervals ?

Ex: k_timer_start(&my_connect_timer, K_SECONDS(60), K_SECONDS(3600)); // To send data every hour but the start of the sample and my intervals don't match now. My sample starts at 17:25:34 and I need to synchronize it to send the first data at 18:00:00. Could you help me explain how tis could be done ?

Regards,

Adeel.

RE: How to schedule events and tasks at particular time intervals

Carl Richard — Thu, 21 Jan 2021 15:13:08 GMT

Hi, Adeel!

You can sample the current time using the Date-Time library of NCS. If you do this on startup, after connecting to LTE, you can start a timer based on the time you get or alternatively submit a delayed work item.

Best regards,
Carl Richard

RE: How to schedule events and tasks at particular time intervals

Adeel — Thu, 21 Jan 2021 12:09:30 GMT

Just an addition that I forgot, my hardware is a: Thingy91 v1.4.0 .