@ScruffR - thanks for this response. I am certainly NOT looking for ultimate precision, and I DO fully understand the limitation of timing in c# ;-)). All I want is a relative millisecond tick, and thats precisely what c# .fff provides.
If I wanted really accurate time - I would as you suggest use GPS or even an old atomic clock receiver would do the job ;-)).
I am simply trying to indicate lapsed time between a command going out, and the response coming back. Its WAY easier to use time and include milliseconds, but if that’s not possible on this CPU then so be it :-((. I DO use this on PIC’s however with much success…but then I have full control over ALL the code.
I am currently using (int)(millis() % 1000l) after displaying the time but the ‘offset’ from zero is ‘annoying’ - thats all ;-)). HH:MM:SS (fff) in my logging.
I fully understand that the clock will ‘drift’, but over a few seconds its pretty damn accurate ;-)).
NB It ‘could’ easily be done with a clock interrupt - which simply resets a (local) millisec counter ‘on the second’ (or even minute/hour), thus ‘syncing’ the two sources - then Time could indeed easily include an fff feature.
Thanks for clarifying though…