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From: dickw@cnps.PHILIPS.nl (Dick Wiersma)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: MIDI
Message-ID: <1502@cnps.PHILIPS.nl>
Date: 15 Nov 90 07:47:49 GMT
References: <4840.tnews@basso.actrix.co.nz> <3341@bruce.cs.monash.OZ.AU> <1990Nov14.052315.988@vax5.cit.cornell.edu>
Distribution: comp
Organization: Philips C&P-LSS
Lines: 28

> In article <3341@bruce.cs.monash.OZ.AU>,
> herbie@bruce.cs.monash.OZ.AU (Andrew Herbert) writes:
> > Isn't there a problem getting an ibm serial port to spit out 31.25kbps
> > as required by midi?

> No... serial ports on most IBM compatibles can communicate at up to 115.2kbps,
> despite IBM's claims to the contrary.  Certain IBM PS/2's have buggy UART
> chips, limiting them to 57.6kbps.  In either case, they would be able to handle
> the 31.25kbps.
> -Sanjay Aiyagari(hd7x@vax5.cit.cornell.edu)

I can't remember how the IBM serial port gets its UART clock frequency but I
do remember that most UART have some built-in divider to obtain its internal
clock frequency from a crystal frequency. This divider (in most cases) is an
ordinary 2^x divider.
By choosing an appropriate crystal frequency they are able to let the UART
"talk" the standard Baud rates like 300, 600, 1200, 2400, 4800, 9600, 19200
and 38400.
When this is also the case in the IBM PC you can forget speeking 31250 which
would be needed for MIDI.

Any suggestions however are welcome.
Did any one try the "serus" serial driver for this? It appeared a week or so
ago in the binaries newsgroup.
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