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

Sun Jul 14 18:54:27 CEST 2019

I see! This makes sense.

Christof

> Gesendet: Sonntag, 14. Juli 2019 um 18:15 Uhr
> Von: "Ingo" <ingo at miamiwave.com>
> An: "'Christof Ressi'" <christof.ressi at gmx.at>, 'Pd-List' <pd-list at lists.iem.at>
> Betreff: RE: RE: [PD] Question about transmission order to serial port [comport] with two independent streams
>
> This would work but require that I change tha way I send my display data.
> Right now I send the command for the line number and first column followed by
> the 20 characters for the entire line.
>
> Using a status byte for the display instead of MIDI would require sending all
> display characters before going back to MIDI or sending the line and column
> number anew for resuming with the display.
>
> Using a unused status byte like 253 (that is one of the 3 bytes that are not
> used at all for MIDI) for each MIDI byte let's me interrupt the display and
> return to it without any new display header information. Hence the MIDI timing
> will most likely be more precise.
> As I had mentioned - I don't want to wait with MIDI for the display to finish
> as MIDI is timing critical while the display isn't.
>
> Ingo
>
>
>
> > -----Original Message-----
> > From: Christof Ressi [mailto:christof.ressi at gmx.at]
> > Sent: Sunday, July 14, 2019 4:52 PM
> > To: Ingo; Pd-List
> > Subject: Aw: RE: [PD] Question about transmission order to serial port
> > [comport] with two independent streams
> >
> > > 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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> > > >
> > > >
> > > >
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