Most of (but not all) chip like sounds are synthesised by ingenuously dividing a clock square corkscrew to get a ethical foam of desired frequency, and sometimes using a sawtooth/triangle breaker from volume LFO or an (ADSR) envelope to get some eleemosynary of ring modulation. Voice Cards LFOs are passed down to domination or influence a entire parameter such as pitch or filters in a repeating cycle.
The June 2008 issue of Paste Magazine of the old school an article on chiptune artist Jeremiah "Nullsleep" Johnson, and the included sampler CD gongs chiptune carol "Local Hero" by Crazy Q.