[sdiy] Techniques for Multiplying MIDI Clock frequency?

Roman Sowa modular at go2.pl
Fri Dec 17 11:46:36 CET 2021

Measure incoming clock period with a timer. Then divide that measured 
timer value by the number you want to multiply the frequency. If you say 
anything between 10 and 100 is fine, then dividing by 32 sounds like 
walk in a park. And that divided value (or simply shifted in case of 32) 
is then loaded as period for another timer that outputs a pulse on overflow.
This way after each incoming clock pulse you get immediate response of 
updated frequency multiplied by 64 (or whatever other value)


W dniu 2021-12-17 o 08:03, Spiros Makris via Synth-diy pisze:
> Hello List,
> I want to experiment with polymetric structures and create "non 
> standard" subdivisions within the standard ones supported by MIDI. I 
> have only worked with the 24ppq, using the timing messages to directly 
> drive the sequencers. I would like a way to multiply the clock frequency 
> in order to increase resolution, let's say by 10 or maybe 100 times, if 
> that's feasible (I think it is?).
> I think this is achieved by a PLL. I understand the basic concepts of it 
> and have used in the analog domain, but never did it in a digital only 
> format. Furthermore, I suppose having an array of hardware peripherals, 
> such as timers and interrupts, and a fairly fast processor (teensy 3.2) 
> could open up other approaches that don't follow the standard PLL 
> configuration.
> This has been on my mind for some time, but I don't really know where to 
> start. Any advice, or resources are greatly appreciated
> Regards,
> Spiros
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