> Secondly, the Jackson Labs advises that since the Fury uses the > external oscillator as its clock, that the oscillator should be > powered up before the Fury itself. I was hoping that I would be able > to use a single power switch to power both the oscillator and the Fury > simultaneously, but now I'm not so sure. Give it a try and see what happens. Or wait and see what Said says. Getting started is one of the messy areas of "digital" design. The general idea is that you have to hold the CPU reset until power is stable and the oscillator is generating a clean signal. To see if a design will work cleanly, you have to find that part of the CPU data sheet, the startup specs for your oscillator, and the specs for the power-up reset logic. If you are lucky, the power-up reset logic is a tiny magic chip that has clean specs. The reset logic is built-in to many of the smaller micros (cost savings), but they sometimes requires some power ramp-up specs. (aka they don't work cleanly in brownouts.) I can't find any startup specs on my copy of the data sheet for the Isotemp OCXO134-10. (Maybe I missed it.) I'm not looking for the stability type warmup time of several minutes. I'm looking for something like a few ms, the time it takes the crystal to get past the startup transient and put out a clean signal even if the frequency isn't right yet. -- These are my opinions, not necessarily my employer's. I hate spam.