Red flashes - Xenon 1.3.0-rc.1 - Assertion Error?

[ScruffR]

That makes more sense now

However, it is actually safer to write a delay loop slightly differently

  while (millis() - previousTime < period);

The rational for that is outlined in this post

Millis() and rollover tutorial

The millis() function is handy for timing things with the Particle Photon (and Electron, and Core). It executes very quickly and has a good resolution (milliseconds). From the manual: Returns the number of milliseconds since the device began running the current program. This number will overflow (go back to zero), after approximately 49 days. Note: The return value for millis is an unsigned long, errors may be generated if a programmer tries to do math with other datatypes such as ints. Now…