[FightCube] wrote in recommending a very helpful piece of circuit simulation software for those of you still constructing entries for the 555 design contest. LTSpiceIV, available from Linear ...

[kodera2t] built this circuit after reaching for a 555 timer a few too many times. It’s a one-chip solution with an ARM core that’s able to generate square waves with 1Hz resolution up to 65536Hz.