[sdiy] bizarre pic-midi issues

[Karl Ekdahl]

> Ask on the ucapps forums and see if
> they can tell you what bugs they ran into

Well i was actually in contact with Thorsten around that time, but since it's been so long (like 5-6 years?) i figured the chips i had had to be the new revision that works. Although maybe it was a 18f2455 i had that i got working... according to the erratas, any version after A3 should work if i'm not mistaken.

Karl

> 
> D.
> 
> On Sun, Apr 18, 2010 at 00:45, Karl Ekdahl <elektrodwarf at yahoo.se>
> wrote:
> > Ingo, Csaba;
> >
> > I tried changing the resistor to a 1K but the 6N136
> couldn't pull it all the way to ground, so i changed to a
> 2.2K which gives me the same results as before. However i
> did verify that the opto and everything works 'cause i
> connected it to a couple of gates to make a MIDI THROUGH and
> the synth at the end of that responded nicely.
> >
> > So yes, there is indeed a problem inside the PIC
> however i'm still inclined to believe that the clocking is
> correctly set because
> > a) it works with MIDI OUT, and
> > b) it gives me good data almost all the time while any
> setting higher or lower gives me framing errors all the
> time.
> >
> > But regardless i could of course be wrong, please
> prove that it's so! :) I am inclined to believe at this
> point however that i indeed am dealing with a silicon bug, i
> noticed that this chip is a revision A3 which does have
> silicon bugs in its EUSART *but* none of the bugs mentioned
> in the six erratas i have are pertaining to asynchronous
> reception in 8-bit mode. Nevertheless, i placed an order
> with Mouser in the hopes of getting a never revision chip.
> >
> > Karl
> >
> > --- Den lör 2010-04-17 skrev Csaba Zvekan <czvekan at gmail.com>:
> >
> >> Från: Csaba Zvekan <czvekan at gmail.com>
> >> Ämne: Re: [sdiy] bizarre pic-midi issues
> >> Till: Synth-diy at dropmix.xs4all.nl
> >> Datum: lördag 17 april 2010 22:18
> >> I use a 6n135 with a 1K pull-up and a
> >> 0.1µF capacitor to ground. It works like a charm
> . Ingo you
> >> have a valid point there . I still think his
> problem is
> >> clocking and settings.
> >>
> >>
> >> On Apr 17, 2010, at 10:02 PM, Ingo Debus wrote:
> >>
> >> >
> >> > Am 16.04.2010 um 20:19 schrieb Karl Ekdahl:
> >> >
> >> >> The hardware i'm using is a PIC18F4550
> connected
> >> with it's RX pin tied to pin 6 of a 6N136 via a
> 2.7K pull-up
> >> resistor,
> >> >
> >> > In the Fairchild datasheet of the 6N136
> propagation
> >> delay times are specified for a pull-up of 1.9k.
> Admitted,
> >> 2k7 isn't that much more, but maybe its worth a
> try using a
> >> smaller pull-up to speed up the optocoupler?
> >> >
> >> > Ingo
> >> >
> _______________________________________________
> >> > 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
> >>
> >
> >
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at dropmix.xs4all.nl
> > http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> >
>