A bit of an update to keep the log alive, because next ping won't come soon.

With input processor done, project now moves to it's right side - the TX part.

And there are at least two ways to go about it.

And both are almost equally tricky:

• port Edge-TX firmware onto my board;
• write my own thing from scratch;

Porting existing thing will obviously require getting into someone's head, study the source project first, see it's ways, pull a handful of hair, then some more and then maybe, just maybe, it'll just click together and take off.

Pros - I will have a close approximation of a full-fledged remote firmware with all the cool stuff RC kids have - Lua scripting, best gimbal processing practices, audio playback, firwmware updates, existing transmitter protocols support and so on. Cons - ports are not trivial. At all. At best I'm looking at a 2+ months endeavor, no less, and most of this path I will have no idea if the board is correct, or should I respin it like I like to do sometimes.

I mean, sure, there will be a basic firmware to test if chips work and if the circuit itself is sound, but Edge-TX expects some things are done in certain way, and it may (and will) happen that whatever I did might not be compatible with those expectations - e.g. I already sorta see the key matrix on an IO expander might not fit well in input subsystem of the project.

That is not to mention that the project is structured radically different to what I'm used to in my simplistic playarounds.

Writing my own TX firmware, on the other hand has lower upfront cost, but It's a laborious process nonetheless, and just like with former case - it's another 3+ month of work, but even then I will have to borrow protocols implementations from other projects and so on. Only to be greeted in the end with a "bare minimum" that is needed to run a simple ELRS transmitter to control a vehicle with uncustomizable gimbal aspect. 

Not ideal either.

Just when I thought it's over, comes a time to dig even deeper, but the bottom feels reachable now.