[sdiy] New TOG board: $0.02 needed

[harrybissell at wowway.com]

If its a TOG, wouldn't it be followed by digital dividers in most cases...
making variable pulse width non-functional ?   The dividers would re-establish
50% duty cycle. There were some TOG that did not output a square wave... is
this to emulate those cases ???

H^) harry





On Wed, 07 Jan 2009 13:25:47 -0500, David Moylan wrote
> Perhaps if the serial data line could be made available and the code 
> implemented a PIC could be programmed later to handle a CV to serial 
> translation (I'd volunteer).  PWM would be great, but if it could 
> only support static width I'd still be quite happy with that.
> 
> Dave
> 
> Tim Ressel wrote:
> > --- On Tue, 1/6/09, David Moylan <dave at westphila.net> wrote:
> > 
> >> Any chance of varying the duty cycle dynamically?
> > 
> > Hmmm. There are 2 problems. The first is getting the data into the part.
Are we talking about varying all 13 note at the same time and by the same
amount? I assume we are. The second problem is more nasty. A variable PWM
would have to be a number that varies from 1 to the max count of the counter
minus 1. The problem is each note has a different max count. So if we try to
load a single PWM number and use it on all the note counters, we get different
PWMs for each note. The lowest note will get a full range while the highest
note will only make it to 50%. I deem this too much to be useful.
> > 
> > So we need to load a different value for each note. This is possible. I'm
note sure it will fit into the current CPLD family I am designing with. And
then the classic design question arises: Serial or parallel load? 13*8 bits =
104 bits to clock in serially. Parallel is quicker, but takes 8 data lines
plus 4 address lines plus one latch line equals 13 lines. That is a lot for a
small processor. Ah, the like of an engineer.
> > 
> > Bottom line: Cool idea, is feasable, it's gonna take some work.
> > 
> > --TimR
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at dropmix.xs4all.nl
> > http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> >
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy


Harry Bissell & Nora Abdullah 4eva