Hi Folks. Thanks a lot for the inputs! I'm still digesting how to use the code snip-its provided.
I also noticed the 2^32 calculation and sent the update (int32_t freq = frequency * 4294967296LL/125000000L;). My freq counter is limited to 10 Hz resolution , so perhaps I am just not able to measure the difference - the output is 9,999,96 Hz when set to 10 MHz output. I'll have to dig out another counter...
I see what you're saying pito, thanks.
I'm still trying to get the faster code to run, and also played with putting the sendfreq call in an encoder interrupt, and that did nothing?