FlexIO is the closest thing on the Teensy to PIO, but it's not quite as "hands-off". Although if you just want to output PWM signals, there's other dedicated modules for that.
Sounds like analogWriteFrequency(pin, freq) and analogWrite(pin, duty) is enough. This will allow you to create (almost) any frequency. The PWM hardware does all the work, so the waveform doesn't depend on software interrupts. Details here...
Also be aware analogWriteFrequency() can accept a floating point number for the frequency, so you're not limited to integer precision. It will automatically make the closest frequency the hardware can create. All the timers have 16 bit...
Thanks! If guess what I really need is a very stable PWM wave that doesn't react to anything that's going on, except the frequency gets updated. It's just a synth, after all, there's not much going on in relation to MHzs of clock, even if I...
Dear PJRC people, there's this great Juno DCO project by Jan Knippers, https://github.com/polykit/pico-dco. It relies on PIO (which seems to be a Raspberry-exclusive thing) to deliver a stable "reset" frequency via PWM to a Juno 106 like sawtooth...