[PD] Question about transmission order to serial port [comport] with two independent streams

[Christof Ressi]

> That is the lowest overhead you can probably get in terms of transmissin and
> fastest MIDI timing.

I don't know what your "display" data looks like, but as I wrote, MIDI is already a protocol, so you can simply take an unused status byte (e.g. 240 = Sysex start) for transmitting your non-MIDI data:

240, <numbytes>, <data0>, <data1>, <data2>, etc.

This would be quite efficient and also easy to parse.

Christof


> Gesendet: Sonntag, 14. Juli 2019 um 16:33 Uhr
> Von: "Ingo" <ingo at miamiwave.com>
> An: "'Christof Ressi'" <christof.ressi at gmx.at>, ingo at dynasample.com, 'Pd-List' <pd-list at lists.iem.at>
> Betreff: RE: [PD] Question about transmission order to serial port [comport] with two independent streams
>
> I actually only need one byte in front of each MIDI byte. After the actual
> value the Arduino resets itself.
> This insures that only MIDI needs one extra byte and nothing else.
> That is the lowest overhead you can probably get in terms of transmissin and
> fastest MIDI timing.
>
> > message passing in Pd is synchronous, so there's no way two messages can
> > interleave.
>
> This answers my question! Thanks, Christof!
> In this case it should work the way I have it in mind.
>
> Ingo
>
>
> > -----Original Message-----
> > From: Pd-list [mailto:pd-list-bounces at lists.iem.at] On Behalf Of Christof
> > Ressi
> > Sent: Sunday, July 14, 2019 4:24 PM
> > To: ingo at dynasample.com; Pd-List
> > Subject: Re: [PD] Question about transmission order to serial port [comport]
> > with two independent streams
> >
> > > The SLIP protocol has actually more overhead than what I'm thinking of.
> >
> > generally the overhead is one byte per message + escape bytes if the data
> > itself contains 192 or 219.
> >
> > > On top of it it is more prone to generate errors with MIDI since it
> > > uses Bytes
> >
> > if used correctly, the SLIP protocol can handle any kind of data (otherwise
> > it
> > would be not a very useful protocol).
> >
> > > Can a message going to comport be interrupted by another message that
> > > is being sent to [comport] almost at the same time or will one message
> > > or packed list always be processed completely before anything else
> > > will be sent to the same [comport] object.
> >
> > message passing in Pd is synchronous, so there's no way two messages can
> > interleave.
> >
> > still you need to think about how to reliably distinguish MIDI from other
> > data
> > in your Arduino, so the advice in my last mail might still apply.
> >
> > Christof
> >
> >
> > > Gesendet: Sonntag, 14. Juli 2019 um 15:58 Uhr
> > > Von: "Ingo Scherzinger" <eeemail at dynasample.com>
> > > An: "'Christof Ressi'" <christof.ressi at gmx.at>, 'Pd-List'
> > > <pd-list at lists.iem.at>
> > > Betreff: RE: [PD] Question about transmission order to serial port
> > > [comport] with two independent streams
> > >
> > > Thanks, Christof!
> > >
> > > The SLIP protocol has actually more overhead than what I'm thinking of.
> > > On top of it it is more prone to generate errors with MIDI since it
> > > uses Bytes that are also used as MIDI Status Bytes.
> > >
> > > My question is actually very simple:
> > >
> > > Can a message going to comport be interrupted by another message that
> > > is being sent to [comport] almost at the same time or will one message
> > > or packed list always be processed completely before anything else
> > > will be sent to the same [comport] object.
> > >
> > > Ingo
> > >
> > >
> > > > -----Original Message-----
> > > > From: Christof Ressi [mailto:christof.ressi at gmx.at]
> > > > Sent: Sunday, July 14, 2019 3:32 PM
> > > > To: Ingo; Pd-List
> > > > Subject: Aw: [PD] Question about transmission order to serial port
> > > > [comport] with two independent streams
> > > >
> > > > When sending data over a serial connection, it's good to have some
> > > > sort of protocol to distinguish messages. A very common protocol is
> > > > SLIP https://en.wikipedia.org/wiki/Serial_Line_Internet_Protocol
> > > > It's often used for streaming OSC messages (e.g. TCP or serial). You
> > > > can encode in Pd with [mrpeach/slipenc] and decode on the Arduino
> > > > with https://github.com/CNMAT/OSC/blob/master/SLIPEncodedSerial.h
> > > >
> > > > On the other hand, MIDI is already a protocol (messages are
> > > > delimited by status bytes) and you could send your display data on
> > > > an unused MIDI channel or even as Sysex messages.
> > > >
> > > > Christof
> > > >
> > > > > Gesendet: Sonntag, 14. Juli 2019 um 14:59 Uhr
> > > > > Von: "Ingo" <ingo at miamiwave.com>
> > > > > An: 'pd-list' <pd-list at iem.at>
> > > > > Betreff: [PD] Question about transmission order to serial port
> > > > > [comport] with two independent streams
> > > > >
> > > > > Hi there,
> > > > >
> > > > > I need to send both display data and MIDI out data to the same
> > > > > serial port via USB using [comport] going to an Arduino Micro.
> > > > > The MIDI goes on to the serial transmit pin and the display goes
> > > > > to the I2C pins.
> > > > > Unfortunately neither the display nor the MIDI data is very
> > > > > predictable concerning timing.
> > > > >
> > > > > The display uses drip to send one character after the other and
> > > > > MIDI is sending out manipulated data from the MIDI input whenever
> > > > > MIDI
> > > > comes in.
> > > > > Both senders are on different sections of the software and are not
> > > > > synchronized in any way.
> > > > >
> > > > > Since I need to find a way to split up each stream inside of the
> > > > > Arduino without meshing them up and causing errors my question is:
> > > > >
> > > > > Does Pd send one message (or packed numbers) with two or more
> > > > > values without interruption?
> > > > > If yes I could simply prepend an unused number (like e.g. 253 or
> > > > > 254) as a header in front of each MIDI Byte.
> > > > > If needed another one for the display data.
> > > > > (The latter is probably not necessary since I can reset after each
> > > > > MIDI Byte inside of the Arduino to keep sending again to the
> > > > > display.)
> > > > >
> > > > > Meshing up MIDI and display data would be absolutely chaotic!
> > > > > If I can't guarantee that each Byte goes to the correct
> > > > > destination I will have to use two separate arduinos.
> > > > >
> > > > > Thanks!
> > > > > Ingo
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
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