Espruino on ESP8266

It would be easy to create a timer interrupt, but that will run on some random FreeRTOS thread and it won't be able to safely perform any network I/O.

That's perfect - if it was accurate (ish - 0.01ms?). this code expects to set up a call to jstUtilTimerInterruptHandler after a set time period. The IRQ works off its own circular buffer, so shouldn't interfere with much and definitely doesn't call into any OS functions (apart from GPIO or analog IO).

It's for digitalPulse, waveforms, and Espruino's software PWM