[sdiy] damnable digital interface.

cyborgzero at comcast.net cyborgzero at comcast.net
Sat Aug 3 07:21:36 CEST 2002

There is a standalone chip that will do it for about $10 usd..

Then, there is the flipflop with reset solution, which also seems to
work okay. I actually got that working long ago, and it tended to work
pretty well..

I hooked the outputs of the flop to a 4066 to close the switch, and it
worked really well.. Some fine tuning on the pulse widths coming from
the flop, and it worked very well.. Better than most micro based

There is a bobble state in the quadrature output that most don't
compensate for, and is easy to ignore in a uP based solution, but a
discrete solution will still work.


----- Original Message -----
From: "Batz Goodfortune" <batzman at all-electric.com>
To: "Tim Parkhurst" <tparkhurst at siliconbandwidth.com>; "'Steve Begin'"
<Steve.Begin at pwgsc.gc.ca>; "Synth (E-mail)"
<synth-diy at dropmix.xs4all.nl>
Sent: Friday, August 02, 2002 10:29 PM
Subject: RE: [sdiy] damnable digital interface.

> Y-ellow Steve, Tim and everyone. (except Jim who trashes my posts.
>          Dare I say it but probably the best way round the rotary
> problem would be a small micro to interpret it. Some would say this
> without saying but I say nay and say there's more to it than they.
> really got to stop reading Dr. Suese.)
> Apart from the lead/lag encoding these things spit out, you'll
> find that there's a timing issue with the Polly it self. Put simply,
> polly is a bit light-on for CPU power and probably couldn't read the
> switches as fast as the encoder can spit them out. I suspect the
> would be rather like a non-de-bounced switch. Somewhat hit or miss.
> under/over shoot in this case.
> I don't know how the debouncing is done in the Polly but knowing
korg it'd
> be half assed to make up for the lack of processing power. At the
> least you're going to miss pulses. At worst it could be the synth
> equivalent of a DoS attack. (Denial of Service) Where the synth
locks up
> under the weight of it's own interrupts.
> You could decode the rotary encoder with a little bit of logic but
with a
> micro as middle man, you gain some control and extra functionality
> would otherwise not be practical. Depending on the number of pulses
> spit from the encoder per rev, you could decided to either
accumulate those
> pulses and spit them out in an orderly fashion. OR. You could
decided that
> you are going to skip pulses that fall outside the timing range. Or
> some combination of both. Not only that but you could select which
> of buttons the encoder will control. Not just the up/down buttons
etc. Even
> getting way too smart for your own good and getting it to control
> sequences of key presses.
> Now one more little idea I'd had in the back of my mind along these
> for some time. (Hey it almost rhymes) IS, in a word. "Mouse Balls"
> There's a nice little optical encoder inside a mouse and the mouse
it self
> does all the interpreting for you. So I've been toying with the idea
of a
> bit of code in a micro somewhere that can read mouse droppings and
> determine their origins. It might be tricky but you could, if you
> mount the mouse wheels as knobs on the front panel, or even
better... Get
> one of those touch pad things and mount that to the front panel.
Would that
> be cool or what?
> A Polly 800 with a touch pad. Oooooo. Make a neck for the thing and
play it
> like a guitar even.
> I'm pretty sure there's mouse reading code out there for most small
> embeddeds if you needed to use it.
> Hope this helps.
> Be absolutely Icebox.
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