Re: [LAD] basic MIDI note-on/note-off questions

On Fri, 2010-06-25 at 15:36 +0200, Ralf Mardorf wrote:
> On Fri, 2010-06-25 at 14:38 +0200, Ralf Mardorf wrote:
> > On Fri, 2010-06-25 at 08:29 -0400, Paul Davis wrote:
> > > On Fri, Jun 25, 2010 at 6:55 AM, James Morris <james@email-addr-hidden-art.net> wrote:
> > > > Hi,
> > > >
> > > > I keep getting surprised at some of the most basic problems I run
> > > > into... This time, processing order.
> > >
> > > just remember that in "real" MIDI, nothing can be simultaneous. its a
> > > serial protocol without timestamps. with traditional serial MIDI, the
> > > time interval between bits and bytes is also fixed, creating a fixed
> > > minimal interval between any two note on/off messages.
> >
> > In addition, the UART gives information about being ready to send. It's
> > not fixed to e.g. 1ms. There's a register giving this information.
>
> Note, there's nothing fixed, the limitation is just for the max Baud
> MIDI is able to do. Regarding to the term 'fixed' UART is for 'Universal
> Asynchronous Receiver Transmitter', the important word is
> 'Asynchronous'. We are talking about microseconds, taking care about the
> CTS and RTS registers. Regarding to all that MIDI jitter, I wonder if
> ALSA seq, might has to do with it. I don't know, perhaps there are
> issues for USB specifications, but maybe there's something bad for this
> 'timestamp' routs.
>
> *?*
>
> I programmed on Assembler directly using the UART and there never was
> jitter.
>
> Could this be a reason for MIDI jitter using Linux or has it nothing to
> do with it? Because, at the other hand there's no jitter internal the
> studio in the box.
>
> *?*
>
> Ralf

I can't remember, perhaps CTS and RTS are flags in one register and
maybe they have other acronyms ;), anyway, this is the important stuff.
Pedro Lopez-Cabanillas did post the technical specifications.

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Received on Fri Jun 25 20:15:02 2010