Synchronizing flashing LEDs and RTCs

[atferrari]

There are three independent 16F877 (eventually 16F628), (no clock sharing), monitoring three inputs each. Depending if set or clear plus other internal variables the respective LEDs will flash, stay permanently on or permanently off.

Additionally, each micro would be fitted with an RTC DS1307 for timestamping when the inputs go high.

Being the three micros in the same functional level (exactly the same software with no one being master/supervisor of the rest) and without any additional glue logic, how could I:

a - Have the required LEDs in the different modules, flashing at the same pace, even if a module (any one) is turned off?

b - Have the three RTC synchronized for a meaningful time stamping?

No one will be master of the rest and no data will be passed to anyone.

Thanks for any good idea.

 

[Pommie]

A few questions,
Will the 3 pics communicate with each other?
If so, how?
Are the LED's of one pic dependent on the inputs of another pic?
How accurate does the RTC synchronization have to be?
How is this different from having 3 PCs logging data?

A better explanation of the application may help.

Mike.

 

[atferrari]

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.

 

[Nigel Goodwin]

Sorry, but the idea sounds completely pointless?, and a LOT of work to try and do, for no practical purpose.

If you want a multi-PIC robot, I strongly suggest you have one as main controller, and the others as slaves!. Probably a good solution is a larger chip as master (16F877 or similar) with smaller PIC's as the slaves.