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Author Topic: Possible to create a series/parallel shift register based sequencer?  (Read 2501 times)

Synthetech

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Here's an example of what I'm thinking of,


vimeo.com/35987839


this is also similar to the Klee Sequencer-

www.birthofasynth.com/Scott_Stites/Pages/Klee_Birth.html





The shift registers I was thinking of  doing a combination of parallel to series back to parallel output.

So say we have 8 switches to create a pattern that loops.  That 8 bit/byte pattern will hold into a buffer that gets cleared/set upon a determined clock signal...

The 8 bit pattern will be fed out in parallel fashion to select bit inputs of 8 more shift registers.

So say bit0 gets injected into serial shift reg. 1 at bit 0.
... bit 1 gets injected into serial shift reg. 2 at it's bit 4
... bit 2 gets injected into serial shift reg. 3 at it's bit 7..

the idea is to break up the initial pattern and feed it into the 8 extra shift registers running in serial mode forward.. the timing of the bits going down the stream will be broken up so they are not output at the same time.


To make things more interesting, make it so the pattern buffer can shift right/loop, left/loop or fwd/back/fwd loop.
Also make these features available to the other shift registers.. that way additional patterns can be created.
Give different ways to clock the registers with each other as well.


I'm finding it fairly easy to mix up the patterns, but what I was thinking of doing was to synch into the keyboard's select matrix..  perhaps have it so the select line will trigger a section of the sequence.. a snapshot of the final pattern at any moment of the sequence created by the mixed shift registers.

So the hard part for me is a matter of figuring out how to get the patterns into a keyboard matrix.. like say on a Yamaha PSR-12' s keyboard matrix.
How to go about getting a snapshot of the pattern created by the shift registers slipped into the matrix output so that the select line for a particular group of keys is synched as you need it to be with your pattern outputs.

I would think there's a way to come up with some cool patterns.. maybe even a simple arpeggiator??


« Last Edit: December 05, 2012, 11:08:17 PM by Synthetech »
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Gordonjcp

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Re: Possible to create a series/parallel shift register based sequencer?
« Reply #1 on: December 11, 2012, 01:10:54 PM »

I believe what you have described there is a Linear Feedback Shift Register, commonly used to generate pseudorandom sequences.
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Synthetech

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Re: Possible to create a series/parallel shift register based sequencer?
« Reply #2 on: December 20, 2012, 12:04:45 AM »

I believe what you have described there is a Linear Feedback Shift Register, commonly used to generate pseudorandom sequences.


in part... but more 3 dimensional in design..

So we'd have a parent LFSR shifts fwd or backwards.. that branches out to 8 child LFSR's that can independently shift fwd/bkwd..  they in turn feed a buffer or another LFSR that can also go fwd/bkwd.
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