Hi
I would like to code a LFO with different waveforms (sin, square, saw for example) in order to modulate a CC value.
It would be sync to the BPM received by the midi In.
It seems that Audiocommander did something to get the bpm with the clockbox.
Any other idea ?
Cheers
Hi julienvoirin,
to get the BMP is a relatively trivial task; if you’re working with a master, the current version of the clockBox is already implementing everything. I did some slave-extensions to the code as well.
To generate a square or saw waveform should be no prob: you just have to set up a timer (or use the relevant functions in the clockBox example) and change the form appropriately.
Generating a sinus wave in C - however sounds like trouble to me, because (as you surely know), there are no highLevel mathmatical functions on the PIC. So I guess you have to find some ASM-optimized code for this (MB SID? MB FM?).
Dunno if something helpful can be found in the lib; but I’m no friend of this lib anyway, because it blows up your code dramatically - and I’m not sure if it’s as efficient as it should be.
Hope this helps
best,
Michael
thnaks for a so fast reply
slave-extensions
the clockbox must be sync to the BPM. I 'll dig onto your code.
some ASM-optimized code for this (MB SID? MB FM?)
hardcore ! but good idea
can be found in the lib
what is this lib ? sdcc ?
thanks again
I would look to two places - MIOS code, and piclist.com
It’s better to generate the sine wave table-based
The analog toolbox has some code for this, you can easily create any periodic waveform (just have a look into lfo.c and map.c)
Best Regards, Thorsen.
Brilliant!
azz- I ought to think of lookup-tables in my first post…
Cheers,
Michael 