MIDI

Robert J. Granvin rjg at sialis.mn.org
Sun Jul 9 05:30:14 AEST 1989


>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 at sialis.mn.org
____National Computer Systems____          BITNET: rjg%sialis.mn.org at cs.umn.edu
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 "I'll just go bang my head on a wall & figure out why I abuse myself so much"



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