so, judging by this diagram ( http://www.arduino.cc/en/Hacking/Atmega168Hardware )of the pin-mappings for an atmega168, you should be able to remove the chip after burning it with the bootloader and a sketch for standalone operation, right? Simply connect inputs to corresponding pins on the chip, etc.?
You'd have to power it with a battery or some other power source (and I assume, regulate that power source to provide the correct voltage), and I suppose add resistors to compensate for the lack of the arduino's internal pull-up resistors, but it would work correctly otherwise, right?
Has anybody tried this? Maybe it's an obvious question.
It should work fine. One thing, though. You'll also need a 16 MHz oscillator and supporting capacitors, unless you change the fuses on the chip (using a hardware programmer) to work on the internal oscillator.
Yep. You can also continue to run the ATmega from its internal clock when it's on the Arduino board, if you don't want to have to change the fuses every time.
It should be fine. The LilyPad also runs at 8 MHz, so I've adjusted most of the core to work at either speed. The PWM frequency will be different, but everything should work (and the delays should be correct).
I'm also in process of breadboarding around a pre-burned ATmega168.
Picked up a handful of 16 mHz resonators at Digi-Key earlier this week. As I understand it, a couple of filter caps, a regulated supply, and the resonator is most of what I need to get a "naked" Arduino running.
(I'm tinkering on a project where I just don't have space for the full diecimila and shield).
add resistors to compensate for the lack of the arduino's internal pull-up resistors
Unless I misunderstand you, what you refer to as "Arduino's internal pull-up resistors" are actually the "atmega168's internal pull-up resistors" so they are internal to chip and so "come along for the ride" when you make it stand-alone.