Xref: utzoo unix-pc.general:3251 comp.os.os9:536 comp.protocols.misc:615
Path: utzoo!attcan!uunet!cs.utexas.edu!csd4.milw.wisc.edu!srcsip!tcnet!nis!sialis!rjg
From: rjg@sialis.mn.org (Robert J. Granvin)
Newsgroups: unix-pc.general,comp.os.os9,comp.protocols.misc
Subject: Re: MIDI
Keywords: unix-pc, electrical and protocol
Message-ID: <1650@sialis.mn.org>
Date: 8 Jul 89 19:30:14 GMT
References: <8928@ihlpf.ATT.COM> <813@flatline.UUCP>
Reply-To: rjg@sialis.mn.org (Robert J. Granvin)
Followup-To: unix-pc.general
Distribution: unix-pc
Organization: Dr. Ho Laboratory and Day Care Center
Lines: 36

>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.




-- 
________Robert J. Granvin________        INTERNET: rjg@sialis.mn.org
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 "I'll just go bang my head on a wall & figure out why I abuse myself so much"