I'm looking to use the PWM outputs from my IC to produce an analogue value
using an RC network. Unfortunately everywhere I've found in searching only
gives calculations for if i want analogue waveforms, not flat constant (as
possible) outputs. Is this going to be a trial and error thing where RC
sizes are systematically swapped or is there a known method of
approximating? I can alter my PWM frequency (and obviously duty) as needed.

Cheers
J