Not aclear idea yet, Pommie
Will the 3 pics communicate with each other? If so, how?
Not clear how but probably with two pins each (not I2C, I guess)
Are the LED's of one pic dependent on the inputs of another pic?
Not at all. Each micro its own inputs/LEDs.
How accurate does the RTC synchronization have to be?
The best possible within the second in case I want to compare each unit timings
How is this different from having 3 PCs logging data?
Not even a single PC involved here.
Timestamping just in case I want to read later a record. For the moment, LED synchronized properly are my priority.
The application is in a robot where I want to have a clear visual indication of what's going on.
LEDs off: "not running- Everything OK"
LEDs on: "running- everything OK"
LEDs flashing: "Something is not going OK"
So many flashes unsynchronized, besides annoying could be confusing.
Can not give more details because I couldn't work out a more detailed idea yet.
No secrets kept here
Thanks for replying.