[comp.protocols.misc] MIDI

gmark@ihlpf.ATT.COM (Stewart) (07/07/89)

I'd like to eventually get together a MIDI interface for my PC, which
happens to be a 3B1.  So, first, I'd like to get a description of
the pinouts of those funny little MIDI connectors on my keyboard.
In other words, I'd like to get a hold of the electrical and
protocol specifications of the MIDI interface.  Anyone out there
care to share their knowledge or experience? Horror stories welcome.
If not of general interest, e-mail is preferred. Thanks in advance.


				- Mark

				G. Mark Stewart
				ATT_BTL, Naperville, Ill. ix1g266
				ihlpq!gms (312)979-0914
				(please include phone for response)

erict@flatline.UUCP (J. Eric Townsend) (07/08/89)

Out of curiosity, why is this on both u-p.g and c.o.os9?

In article <8928@ihlpf.ATT.COM> gmark@ihlpf.ATT.COM (Stewart) writes:
>I'd like to eventually get together a MIDI interface for my PC, which
>happens to be a 3B1.  So, first, I'd like to get a description of
>the pinouts of those funny little MIDI connectors on my keyboard.

MIDI is a serial protocol.  Only two of the wires are actually used.
(Ever build a unix-to-unix serial line with just two wires?  That's
they way MIDI works.)

A recent issue of Amiga Transactor had a do-it-yourself RS232 <-> MIDI
project that consisted of one correctly placed resistor.  Now you
just have to deal with the UNIX lack-of-precise-timing problems that 
are involved.  "Dr. Dobbs" has a book called (I think) _C Programming
for MIDI_.  It's wrapped around the PC, of course, but I think you
could easily munge many of the functions to unix.

Also, there is a package "glib" (pronounced as one syllable: "guhlib"),
that is a patch librarian/editor.  It runs on a variety of platforms,
and has code for several major synths (and instructions on how to write
it for your own system).
-- 
"Dope beats and lyrics -- no beepers needed."
J. Eric Townsend -- uunet!sugar!flatline!erict  || cosc5zz@george.uh.edu
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EastEnders Mailing list: eastender@flatline.UUCP

rjg@sialis.mn.org (Robert J. Granvin) (07/09/89)

>Out of curiosity, why is this on both u-p.g and c.o.os9?

Lotsa MIDI software/hardware available for os9?

>>I'd like to eventually get together a MIDI interface for my PC, which
>>happens to be a 3B1.  So, first, I'd like to get a description of
>>the pinouts of those funny little MIDI connectors on my keyboard.
 
>MIDI is a serial protocol.  Only two of the wires are actually used.
>(Ever build a unix-to-unix serial line with just two wires?  That's
>they way MIDI works.)
 
>A recent issue of Amiga Transactor had a do-it-yourself RS232 <-> MIDI
>project that consisted of one correctly placed resistor.  Now you
>just have to deal with the UNIX lack-of-precise-timing problems that 
>are involved.  "Dr. Dobbs" has a book called (I think) _C Programming
>for MIDI_.  It's wrapped around the PC, of course, but I think you
>could easily munge many of the functions to unix.

Correct me if I err here, but MIDI runs at (or about) 38.4K baud.
This is why it's so easy to make an RS232 <-> MIDI interface for the
Amiga, since the Amiga serial ports run at 56.4K, and why you can't do
this for most PC serial boards, since they only run a max of 19.2K.

This problem would still exist for the 3b1, the serial ports being
driven a maximum of 19.2K.  You'd have to devise some special hardware
modification to do the work.




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