installing espruino on stm32F100 based diy project

maybe try some different places, but as a start:

• Stick one at the beginning of jshIdle (https://github.com/espruino/Espruino/blob/master/targets/stm32/jshardware.c#L1349) and another at the end that sets to 0.
  
• Try one around jshDoSysTick (https://github.com/espruino/Espruino/blob/master/targets/stm32/jshardware.c#L745) - ideally on a different pin but if not take turns.
  
  

Ideally they should both end up getting called and flashing the LED.

You could also try this at the end of jsiSoftInit (https://github.com/espruino/Espruino/blob/master/src/jsinteractive.c#L438)

jsvUnLock(jspEvaluate("setInterval('LED.toggle()',500)", true));

In fact maybe just try doing that last one on its own - if the LED flashes then Espruino is working, it's just the serial that's not set up right.