This post (and the FB post), and the associated comments started ye olde neurons firing, and I was wondering: how difficult would it be to set up 3 RPi/Beaglebone devices which are accurate to within 100ns of each other?
Agreeing with each other to within 100ns, should be possible when they're physically close to each other and share a PPS signal. Being accurate to within 100ns would be considerably more challenging I'd think.
That alone won't do, I'm afraid. 100ns is a tough target for Linux on a RPi. I'd think in addition to the PPS a 10MHz reference would be needed. I don't see how the Pi can count those in hardware (perhaps its worth to you to use one core for that in rt-linux?). The Beagle Bone {Black, Green, Blue ...} with its PRU is probably the more promising platform for such.
