[sdiy] 566 Functional Replacement

Sun Mar 18 16:39:56 CET 2018

LPC800 Cortex M0. for a while these 32-bit ARM CPUs in DIP were praised as
the successor to the atmega by the maker crowd but it seems the lack of
industrial success made them disappear more or less...

On Mar 18, 2018 16:36, "Tom Wiltshire" <tom at electricdruid.net> wrote:

> That’s a powerful little chip. Does anyone know what processor that is?
> The documentation only describes it as "NXP 60 DMIPS”, which doesn’t help
> much.
>
> The NXP website doesn’t seem to let you do a parametric search on all
> their products at once. Instead you have to search each of many product
> families individually…sigh.
>
> Tom
>
> ==================
>        Electric Druid
> Synth & Stompbox DIY
> ==================
>
> > On 18 Mar 2018, at 15:09, Vladimir Pantelic <vladoman at gmail.com> wrote:
> >
> > but then 8 pins is enough for a whole "synth" ;)
> >
> > http://www.synthtopia.com/content/2014/04/23/the-dsp-g1-
> synthesizer-a-tribute-to-the-synths-of-the-70s-80s/
> >
> > On Mar 18, 2018 15:49, "Tom Wiltshire" <tom at electricdruid.net> wrote:
> > This is the 3340 again. It’s 16-pin not 14-pin, but its basically what
> you’ve just described.
> >
> > If you want a 8-pin VCO, perhaps a little PIC thing would work? You’d
> only get 0-5V output, and 0-5V CV input, but you could have whatever
> waveforms you wanted. Something like this, but for audio rates? -
> >
> > https://electricdruid.net/datasheets/STOMPLFODatasheet.pdf
> >
> > Tom
> >
> > > On 18 Mar 2018, at 08:26, rsdio at audiobanshee.com wrote:
> > >
> > > I say let go of the 8-pin restriction. Put all three waveforms on a
> 14-pin chip and you might not need any op-amps. No need for two variations
> of the same chip just to trade one waveform for another. Sure, 8-pin isn't
> "tiny" but a full-featured OSC that's the size of a quad op-amp would still
> be quite small.
> > >
> > > You might still need an external capacitor or two for the various wave
> shaping, so they could use some of the extra pins. Actually, you could add
> Sync, PWM or other shape modulation, Sawtooth, and perhaps Sinusoid. The
> latter might be difficult without more support, unless you don't care about
> purity. That all fits in 14 pins, it seems.
> > >
> > > Brian
> > >
> > >
> > > On Mar 17, 2018, at 11:59 PM, Tim Parkhurst <tim.parkhurst at gmail.com>
> wrote:
> > >> The only problem with removing the square wave output is that an
> external tri to saw shaper needs the square to flip precisely at the peaks
> of the triangle. This happens naturally in the internal comparator of a
> typical tri core oscillator, whereas it's tricky to get precisely right
> with an external comparator (if the tri amplitude changes even a little, it
> can throw the phase relationship off). There's other waveshaping tricks
> like tri suboctaves that you can make if you've got both the tri and square
> waves from the internal circuitry.
> > >>
> > >> Tim (Hip to be square wave) Servo
> > >>
> > >> On Sat, Mar 17, 2018 at 11:23 PM, Pete Hartman <
> pete.hartman at gmail.com> wrote:
> > >>> I'd ditch the square wave and use wave shaping for everything beyond
> the triangle....
> > >>>
> > >>> On Sun, Mar 18, 2018 at 1:19 AM, Tim Parkhurst <
> tim.parkhurst at gmail.com> wrote:
> > >>> Not sure if you'd need a GND pin for reference. Op amps don't, but
> then again, they're not charging and discharging caps. Okay, so if we need
> a ground pin, I'd say to ditch the Linear CV input.
> > >>>
> > >>> Tim (or we could make it a 9 pin chip) Servo
> > >>>
> > >>> On Sat, Mar 17, 2018 at 10:32 PM, Pete Hartman <
> pete.hartman at gmail.com> wrote:
> > >>>> Wouldn't you need a ground pin for reference?
> > >>>>
> > >>>> On Sat, Mar 17, 2018 at 10:07 PM, Tim Parkhurst <
> tim.parkhurst at gmail.com> wrote:
> > >>>>> What the world really needs is a minimalist 8-pin chip VCO (DIP
> and SOIC flavors, please). 7 or better octaves of 1v/o tracking (externally
> trimmed CV) would be a huge plus. In case any chip makers or millionaires
> are listening, I'd make the pins:
> > >>>>>
> > >>>>> +V (9 to 12V)
> > >>>>> -V (9 to 12V)
> > >>>>> Expo CV In (0 to -V so that you can use a single op amp as an
> inverting CV summer, temp compensation built into the on-chip expo)
> > >>>>> Linear CV In
> > >>>>> Cap pin 1
> > >>>>> Cap pin 2
> > >>>>> Tri out (+/-5V with +/-12V supplies)
> > >>>>> Square Out (+/-5V)
> > >>>>>
> > >>>>> Things like Sync, PWM, Saw out, Sine out could easily be done with
> external op amps, but only if needed. Maybe make a second version with Saw
> instead of Tri.
> > >>>>>
> > >>>>> On Sat, Mar 17, 2018 at 1:25 PM, Tim Ressel <timr at circuitabbey.com>
> wrote:
> > >>>>>> I hear ya, guess I miss having a tiny solution.
> > >>>>>>
> > >>>>>> --tr
> > >>>>>>
> > >>>>>> On 3/17/2018 12:00 PM, Dan Snazelle wrote:
> > >>>>>>> Honestly now that the Cem vco  is back in production , in prices
> lower than the 566 (especially in quantity ) I would think that chip would
> be a better bet.
> > >>>>>>>
> > >>>>>>> You basically want an OSC on a chip that has multiple waveforms
> right ?
> > >>>>>>>
> > >>>>>>> On Mar 17, 2018, at 1:27 PM, Tim Ressel <timr at circuitabbey.com>
> wrote:
> > >>>>>>>> A while ago I asked for circuit ideas to use my rare 566s in.
> The more I got into the suggestions the more I realized just how useful the
> 566 was. And the more sad I got that its gone.
> > >>>>>>>>
> > >>>>>>>> I am looking for a functional replacement for what the 566 used
> to do for us. A small, low part count vco design that covers more or less
> what the 566 did. I would prefer analog over digital because some uses,
> like noise modulation, may not work so well with a digital solution.
> > >>>>>>>>
> > >>>>>>>> I have looked at the 4046 design but it requires some
> components, especially if you want triangle output. There was a tri-core
> design I saw somewhere online that was real tight. I think it was a 13700
> based circuit. But I can't find it now. The is the KA331 but it is DIP only.
> > >>>>>>>>
> > >>>>>>>> Hmm .. maybe I am out of luck.
> > >>>>>>>>
> > >
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