It's convenient to use this one clock frequency, no doubt about it. However, it's possible to provide a standard baud rate without it, if it's really important to do so. However, so many app's use this frequency, and I see plenty of them in ad's and technical papers that cross my desk all the time, that don't even use the serial port, though they all seem to provide one. It simply troubles me that so many people are willing to slave their system timebase to a frequency that is non-essential to their application.

Marketing literature frequently trumpets the "high-performance" of their MCU, yet when the evaluation board is published, it has that 11.05 MHz (or a harmonic of it) crystal. The MCU can operate at 24 MHz, but it comes with a 22.1 MHz crystal. It's not even a 10% difference, but you'd think they'd want to demonstrate their product at the extreme. I've seen 805x-core MCU's that operate "under the hood" in automobiles that don't even need to adhere to that frequency "standard" yet they have that crystal on board. Today's cars use a handful of this sort of device working in concert, but, when I looked into an 805x-core MCU for that market, clearly designed for 4-cylinder auto applications, its EV-board was equipped with that 11 MHz crystal even though the accompanying app documents didn't even use the serial port. It just strikes me as totally limiting. I'd have thought the "community" would, collectively, have shown more imagination than this suggests.

RE