I'm not familiar with the USB spec. It happened I did tear-downs of flashdrives to find-out which ucontroller there is and try to dump stuff, etc... (For anyone

I'm not familiar with the USB spec. It happened I did tear-downs of flashdrives to find-out which ucontroller there is and try to dump stuff, etc... (For anyone interested, look up VID:PID and Google some microcontroller chip. It's a fascinating world where Russians are very present). Your second comment about a lot of hw initialization being based on polling gives place to an "a fortiori": Why cascade this necessary evil to software. It's true, in the beginning, writing code for microcontrollers, you avoid working with interrupts. You work with assembly language, and get a bit lazy and hard-code delays (and even then, I'd choose a longer delay than the one specified as "max" in the datasheet : it's not like a chip not performing as well as is written in a datasheet never happened, so I take my precautions). But then battery life reminds you of bad code practice: This continuous polling is draining. (And you put the uc to sleep :) ) Even more, if the application's involving sensors there's no way around using interrupts. Unless the thing is powered by a wall-socket, but even then, you get your consciousness preventing you from sleeping at night thinking about that horrible, barbarian code you put in there. But then again, I don't know the USB spec and this may change so it's cool. And they have come a long way.