| Title: | * * Computer Music, MIDI, and Related Topics * * |
| Notice: | Conference has been write-locked. Use new version. |
| Moderator: | DYPSS1::SCHAFER |
| Created: | Thu Feb 20 1986 |
| Last Modified: | Mon Aug 29 1994 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 2852 |
| Total number of notes: | 33157 |
I've just started writing some MIDI software for my DX-7. I have
a problem which is probably well-known to anyone who has tried to
do so on any computer. When the DX-7 powers up, it sends an active
sensing message, followed (after the active sensing message 'times
out', I believe) by note off commands for all its notes, and then it
goes into a loop sending 'system exclusive, YAMAHA-manufacturer-ID'
bytes. Note that the sys-ex-YAMAHA bytes are not followed by a
EOX (end system exclusive) byte as per the V1.0 standard. John
Sauter told me that this was known to be a quirk of the DX-7 since
it was one of the first synths to implement MIDI and got it wrong.
I have two questions:
1) How can I tell the DX-7 that MIDI is alive and well, so please
be quiet?
2) I thought (maybe I'm wrong) that an active sensing message didn't
'time out' and cause a synth to do any kind of output, but instead
just caused the synthesizer to assume some manufacturer-defined
configuration and 'stand-by'. Am I wrong, or is this yet another
case where Yamaha misinterpreted the spec?
-jim
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 297.1 | My Contribution | DSSDEV::SAUTER | John Sauter | Tue Apr 08 1986 08:17 | 18 |
I am not as sure if my facts as .0 implies. I have only "seen"
a DX-7 through a Roland MPU-401, whereas Jim is looking directly
at the MIDI bus.
My DX-7 and its literature is out on loan, so I can't check the
documentation, but I think the device sends "active sensing" all
the time. If it receives "active sensing" it goes into a mode
in which if it stops receiving "active sensing" it shuts up.
This is to avoid having a note stuck on if the cable is pulled.
I think the ``sys-ex, Yamaha'' messages are another "keep-alive"
message used for the same purpose. I seem to recall a hack in
some of the intelligent interfaces to allow for this message,
since it doesn't terminate properly.
The note offs I find very strange. I hope somebody has some
experience in this area to share with Jim.
John Sauter
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