Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!mit-eddie!bu.edu!dartvax!eleazar.dartmouth.edu
From: squibby@eleazar.dartmouth.edu (Clark L. Breyman)
Newsgroups: comp.sys.atari.st
Subject: Re: 500KHz Midi; Author please reply
Message-ID: <20049@dartvax.Dartmouth.EDU>
Date: 6 Mar 90 19:08:06 GMT
Sender: news@dartvax.Dartmouth.EDU
Distribution: usa
Organization: Dartmouth College, Hanover, NH
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	Someone( I lost that article) posted a question on changing the 
	ACIA clock divide for the MIDI port and winding up with 500KHz.
	I hope this is possible, as it would (with Fred Brooks's MIDINET)
	provide a wonderfull built in networking facility. Unfortunately,
	MIDI was designed for musical applications where noise free operation
	was optimized over bandwidth. This means that, in order to avoid 
	ground loops and the hum that comes with them, all MIDI is opto-isolated
	Current leaves one machine. goes through an LED on the slave and returns	to the master. The two devices are electrically independant. An 500KHz
	sounds to me a lot faster that most opto-isolators can handle. Anyone
	got specs on the OI's in the ST? 

	Along this line, it seems like this could be exploited by Atari the
	way appletalk was exploited by Apple. I assume Senor Small's in-progress
	board uses the serial port or the printer port. Perhaps a hardware
	bypass of the MIDI OI might be in order?

	----------
	Clark