Hi, ChemE. Yes, all good points. Though the macros for toggling digital pins worked in Felix's library, I could not figure out how to do it from the sketch so I abandoned them there. (I could not figure out what to #include to have OUTCLR and OUTSET defined). Unless I can get them working from the sketch, I will wrap the digitalWrites in #if DEBUG_MODE #endifs so that I can easily turn them back on for debug and timing studies. I hadn't thought about the write to the DAC. Will do the same there.
I calculate angle from the X and Y accelerometers remotely because I only want to send data when it is important to send it. Like after the shaft has gone 2° or reached top dead center (TDC). If I do it on the local side, that information will be coming across more slowly and the decisions to use the data will be belated. Doing it on the remote side I can do it nearly instantly. This is especially important for me in precisely indicating TDC.
I should mention that there are changes I made in RFM69.cpp that aren't included in the files I posted. The only one that has survived is the SPI clock speed up. I eventually found that things weren't as stable with the changes to stop SPI thrashing so I took them out. Sorry to say, I even took out the pin toggle speed ups (I can't remember exactly why). I just put them back in and the radio.sends dropped from 1.5 ms to 1.44 ms. Throughput increased from 409 to 419 Hz, so there are 10 Hz recovered.
I've attached RFM69.cpp as I am presently using it. Perhaps you can suggest (or even make) specific improvements there for me to try. You can see my attempts to modify the SPI stuff in a block that is commented out.
If I understood all this better I would pursue these things like you do, but at >400 Hz now, I am less motivated. I'm still willing to try things though but it has to be well spelled out.
