[sdiy] Hardware/software LFO Designs

[MTG]

OK, so I'm thinking of adding an LFO to a microcontroller based project, but 
I'm a total newbie at it. What I'm thinking to start with, is using an 
internal CPU hardware timer (one of those standard 16-bit compare/capture 
thingies) at "X" times the LFO rate to lookup into a table for sine, 
triangle, ramp, etc... then fed to a DAC.  The DAC itself is 12-bit, but I 
don't need or want to consume my whole CPU space with lookup tables. The CPU 
has other things to do too. ;-)

The LFO would be sub 1 Hz to maybe 100+ Hz if I can squeeze that out of the 
micro. I suppose for some waveforms it might be easier to calculate the LFO 
value on the fly. Anyone got a feel for how many bits you need to make a 
decent wave without nasty (unintended) distortion? This isn't meant to be 
ultra-hi-fi, at least not as a first pass, but I don't want it to be crap 
either.  I could easily fit a few 4-bit, 6-bit, 7-bit or 8-bit lookup tables 
in.

Any project sites you can think of to get my juices going? This one was kind 
of interesting:

    Voltage Controlled LFO (VCLFO 9D):
    http://www.electricdruid.com/index.php?page=projects.lfo9

GB