A long standing habit with me is to make sure that whenever possible, any processor for which do the system design blinks at least one LED under software control, and has at least one LED on at any given time. This isn't just whim -- when you've got a headless system, and it's sick, you can knock down the top two problems by looking at the lights: "is there a light on?" -- yes, you've got power, no, you don't; "do you have blinky?" -- yes, the processor is at least basically functional, no, the processor (or software) is dorked.
Now I've got a customer who has a system and who wants the lights to stay on steady. But I really like my little diagnostic (it's saved my hind end numerous time with manufacturing and service personnel).
So, is it too weird to blink the lights under software control at 50 or
100Hz? They'll appear to be steady to the naked eye, but if you wave the instrument in the air (it's hand-held) then a running processor will show you a train of dashes, while a dead one will show you a solid streak.I've got to blink the lights for certain error conditions anyway, so it's not like I'm adding a bunch of work to do this.