[sdiy] OOOOPS!!!! (Top octave CPLDs)

[Tim Ressel]

Hey other Tim (and all),

The TOG project consists of two chips, each one
handling half an octave. This is because of the way I
do the generation, and due to size constraints. I use
a comparator to create the output wave. This allows
duty cycles other that 50/50. The original MK50240
came in a 30/70 version; I wanted to keep that option.
In fact, mine can to any duty cycle. The down side is
the duty cycle is hard-coded in the chip. 

I will be offering the chip set for sale. Price for
the two chip set + sockets will be $20 + $5 S&H

--TR

As far as summing pulse trains to make saw waves, I'm
not sure how that would work. I've seen the Don
Lancaster method of making saw waves by summing 50/50
square waves with resistors, and I've seen the
Simonton design making narrow pulses by gating
together 50/50 square waves. Are you talking about one
of these? Is there a schematic I can look at?

--TR

--- Tim Parkhurst <tparkhurst at siliconbandwidth.com>
wrote:
> Hi Other Tim,
> 
> Would it be possible to with the gates you have to
> generate and sum pulse
> waves of different duty cycles to approximate a saw
> wave? You'd need some
> post chip filtering depending on how close to a real
> saw you wanted to get,
> but I think it would be more versatile to have one
> octave of saw (easily
> converted to pulse or even tri) than 3 octaves of
> square.
> 
> Also, are you going to offer your TOG for sale?
> Sounds like a fun chip.
> Might even make a few bucks. How about creating an
> adaptor socket to make it
> a drop in replacement for existing TOGs out there
> like the S50240?
> 
> Okay, maybe I'm getting carried away here. Just a
> thought though...
> 
> Tim Servo
> 
> **************************
> > -----Original Message-----
> > From: Tim Ressel [mailto:madhun2001 at yahoo.com]
> > Sent: Wednesday, October 30, 2002 10:31 AM
> > To: synth-diy at dropmix.xs4all.nl
> > Subject: [sdiy] OOOOPS!!!! (Top octave CPLDs)
> > 
> > Sorry about that folks!  Was editing a message and
> hit
> > the wrong button.
> > 
> > I was taking a look at my TOG CPLD design and
> noticed
> > I have a few cells left in each chip. This is
> enough
> > to provide 2 dividers for each output note, so the
> > TOGs would provide 3 octaves of notes. Does this
> sound
> > right? Or is there something else I should use the
> > extra space for?
> > 
> > --TR
> > 
> > 
> > __________________________________________________
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> 
> 
>
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