"stop bits"; was: NEC uPD7201 misfeature

Nobody ever calls them DE9, either, always DB9. Doesn't make it correct. (Doesn't make it wrong, either, of course; just pointing out that popularity isn't that reliable a guide.) (a) There can be a more-or-less arbitrary clock phase shift between consecutive characters; (b) PLLs generally take a little while to synchronize - at least a few cycles - which means losing the first few bits; (c) if you know the clock frequency, a PLL is overkill (and still suffers from the foregoing), and, if you don't, it's impossible in general to get it from a single character (as I pointed out upthread with the 312.5 us pulse example). And you can't count on having more than one character to work with. At least, assuming we're still talking async, which I thought we were. Oh, and (d) PLLs are significantly more complex, and thus expensive, than a divided-down high-frequency clock, whereas the latter is good enough for almost all applications. (This admittedly loses some of its force for modern purposes, since either one is ridiculously cheap these days, at least when on the same die as a bunch of other stuff.) /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTML mouse at rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B