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From: rgoodman@cit-vax.UUCP
Newsgroups: comp.sys.atari.st
Subject: Re: reading from the midi port
Message-ID: <2101@cit-vax.Caltech.Edu>
Date: Fri, 20-Mar-87 21:55:54 EST
Article-I.D.: cit-vax.2101
Posted: Fri Mar 20 21:55:54 1987
Date-Received: Sun, 22-Mar-87 22:27:05 EST
References: <14085@cca.CCA.COM> <1932@ihuxz.ATT.COM>
Reply-To: rgoodman@cit-vax.UUCP (Ron Carl Goodman)
Organization: California Institute of Technology
Lines: 31

In article <1932@ihuxz.ATT.COM> burris@ihuxz.ATT.COM (Burris) writes:
>In article <14085@cca.CCA.COM>, m204help@cca.CCA.COM (Keith Hedger) writes:
>> 
>> I am trying to read data from the midi in port on the 520 ST  and
>> am having a problem... 
>
>You do not have enough real time to be doing printf's and/or other screen
>output if the MIDI data is coming in at near the MIDI baud rate. 

I don't think you normally have to concern yourself with that since sequenced
MIDI data does not come in anywhere near the MIDI baud rate.  Each second,
MIDI theoretically can transmit almost 4K, but in reality, it transmits
less than a hundred bytes per second generally.  If you're having a problem
because your sequencer adds timing marks that increase the bytes/sec (still
nowhere near 4K/sec) then simply ignore those bytes.  I have displayed
MIDI data using C.  True, if you are displaying 100 numbers/sec you are
at about the limit, but that is not what caused Keith's original problem
of his program ending before the data was all sent.  That was caused by the
fact that his program thought he was out of data because he read it too fast.

Receiving MIDI data itself takes a small percentage of the processors time 
unless you are transmitting special data (e.g. with a sampling synthesizer you 
might transmit the waveform data).

Ron Goodman

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