The LMIC has a mini-task scheduler built-in - not a RTOS but an element of one. Internally it creates, starts, stops and deletes jobs that the schedule will then process according to the jobs criteria.
They create two jobs for the user - one for data collection and one for sending. The data structure is osjob_t* and that is used by sendjob but it could be called anything because it’s only a placeholder to attach the next scheduled time and the function to call, which is do_send. This requires the job structure as a parameter as that’s how the scheduler calls it, as the structure can hold other information if need be.
All that said, calling do_send should be similar to me calling LMIC_setTXData2 but with some initial checks so it doesn’t try whilst it is already processing. My state flags tell me it won’t be, as my structure is either sleeping, creating a payload or LMIC active.
But I don’t have visibility on all your code so I can’t be sure what else is going on - for instance, I don’t even define the ‘sendjob’.
All of this has to be in the context of me trying many many things summer 2019, including trying to adjust timings and so forth. I stripped out various elements from the main example, had debug of the LMIC on full and read the source code. I arrived at a stable solution that works that I’m happy I’ve not warped time & space to achieve, pragmatic but not ideal. Read the README.md for my archive to get a better picture.
At present for co-developer (usually juniors), leveraging Arduino libraries, I use Uno/Nano/Pro Mini/Nano Every with a RAK4200 module on AT commands. I have done a project using a Nano Every (48K Flash, 6K RAM) with an RFM95 using LMIC to good effect. I’m trying out the Adafruit Feather M0 with RFM95 as this is a first class citizen of the MCCI LMIC repro but like many other of these projects, they tend to stop at the basic examples - your requirement for sleep is very common but it’s not been included as there are other things for the developers to do and it’s possibly a bit application specific.
I’ve been to “Planet Change LMIC Timing” and lost days of my life as I detailed on my repro. I’ve learn’t much since then but I’m not tempted back, I’d rather waste my time re-writing a LoRaWAN stack for smaller devices. I was highlighting that with a forum search you can find other people with similar issues over the years. Question is, do you feel lucky (punk), well do you?
) updated.
that would work in the case my only concern was to have a more precise TX period, but actually my problem is that if the node stays on for more than 2 minutes, instead of the few seconds that many report with the Feather M0, its battery life will be drastically affected, and sadly that’s a key aspect of my project.