Grumpy_Mike:
Or did I misunderstand, whereby, timing is strictly provided by an external clock?
Yes you did ... it is.
I went back and double checked.
I want to take an input square wave (say 1Hz), and have it output the same wave, but delayed by X amount of microseconds (where X is say 1-1,000,000).
His external clock is a 1Hz signal. He requires 1us resolution and repeatability. The external signal can't provide that. The provided crystal isn't accurate enough. And some don't even have a crystal. IMOHO, the crystals provided by CrossRoads should be seriously considered. After pondering it a second, with a 50ppm crystal, I'm pretty sure 2us repeatability is the best you can hope for without changing the crystal.