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From: FILLMORE@EMRCAN.BITNET
Newsgroups: comp.sys.amiga
Subject: Re: RS-232 & MIDI Interface
Message-ID: <9009190233.AA23752@lilac.berkeley.edu>
Date: 19 Sep 90 03:35:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Lines: 32

Yes, it is possible to process MIDI data from AmigaBasic.  I did this a couple
of years ago when I first got my Amiga.  Of course you still need to buy a
MIDI interface to translate between the MIDI and RS-232 electrical signals.

The trick is to open the serial port at a legal baud rate and then switch
to the MIDI baud rate (31250), as follows:

  OPEN "com1:9600,n,8,1" AS 1
  adr1 = &HDFF
  adr2 = &H32
  adr = adr2+adr1*4096
  POKEW adr,(1000000!/(.2794*31250))

Then you can read and write using ordinary I/O statements, such as:

  IF LOC(1)<>0 THEN
    c$ = INPUT(1,1)
  END IF

The variable c$ will contain a byte of MIDI data if there is any present.
I wouldn't advise that you use this technique to play music because you
don't have any control over timing.  It works fine for dumping MIDI data
or for loading/dumping system exclusive data (I wrote a little patch
librarian in Basic).

Good luck!

________________________
Bob Fillmore, Systems Software & Communications     BITNET:  FILLMORE@EMRCAN
  Computer Services Centre,                         BIX:     bfillmore
  Energy, Mines, & Resources Canada                 Voice:   (613) 992-2832
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