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Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!ginosko!usc!ucsd!nosc!cod!bmarsh
From: bmarsh@cod.NOSC.MIL (William C. Marsh)
Newsgroups: comp.sys.ibm.pc,comp.arch
Subject: Re: MIDI on the PC (was Re: programming the com port)
Message-ID: <1660@cod.NOSC.MIL>
Date: 5 Oct 89 20:06:19 GMT
References: <927@eutrc3.urc.tue.nl> <446@usage.csd.unsw.oz> <15046@netnews.upenn.edu> <6403@ficc.uu.net>
Reply-To: bmarsh@cod.nosc.mil.UUCP (William C. Marsh)
Organization: Naval Ocean Systems Center, San Diego
Lines: 39

In article <6403@ficc.uu.net> peter@ficc.uu.net (Peter da Silva) writes:
>In article <15046@netnews.upenn.edu>, silver@eniac.seas.upenn.edu (Andy Silverman) writes:
>> You should probably know that you can't use the 8250 to talk to MIDI easily.
>
>Yes, but.
>
>> MIDI is a current loop, not RS-232 so without hardware modification you
>
>There are many good reasons for buying a MIDI card, but electrical
>compatibility isn't one of them.
>
>The big problem with doing MIDI from a regular IBM serial port would
>seem to be CPU. The machine just doesn't have the guts for it. Maybe
>with a smart serial card. And for your $$$ a real MIDI card would be
>better.
>-- 

Actually, the main problem with doing MIDI on the PC seems to be a lack
of a 'good' timer, i.e., something with resolution better than 18.2 times
per second.  I have software which uses a really simple MIDI interface,
which has just a serial port *and* another timer chip, and it can do
quite reasonably, even on a non-turbo XT!

A major (for me) reason for buying a Roland interface is because everyone
and their brother writes software for that interface, and only one person
(you ;-) will write software for the inexpensive interface.

(BTW, I think there is a problem getting the baud rate correct for the MIDI
interface with normal PC serial ports, as it is NOT 38,400, but 31,250.)

Bill

--------

Bill Marsh, Naval Ocean Systems Center, San Diego, CA
{arpa,mil}net: bmarsh@cod.nosc.mil
uucp: {ihnp4,akgua,decvax,dcdwest,ucbvax}!sdcsvax!nosc!bmarsh

"If everything seems to be coming your way, you're probably in the wrong lane."