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From: miskinis@aisg.enet.dec.com (John Miskinis)
Newsgroups: comp.sys.atari.st.tech
Subject: MIDI (one problem solved!)
Message-ID: <3998@ryn.mro4.dec.com>
Date: 17 Feb 91 23:30:56 GMT
Sender: guest@ryn.mro4.dec.com
Organization: Digital Equipment Corporation
Lines: 21


Hi,

	It seems that the level 6 interrupt handler is at (hex) FC281C
accoring to a memory map I have.  (I loaned it out, but have called in
all documentation I own!).

	I have started writing the level 6 interrupt handler.  I currently
look FIRST in the MIDI ACIA, and then the KEYBOARD ACIA.  If I get a (hex)
61 (UNDO) I exit the program...  Otherwise I display the contents of my
MIDI byte count, MIDI overrun count, MIDI buffer empty count continuously.

	I tested it by attaching my TR505 drum machine to the ST, cranking
the tempo to full, and playing a pattern of several (simultaneous) drums on 
16th notes.  I HAVE NOT HAD AN OVERRUN YET!!!  And upon exiting, I simply
call the MFPINT with FC281C, and the original level 6 interrupt handler
is reinstalled.  Prior to this, the keyboard and mouse were inoperable
without a reboot every time I exited my program...

	But, until I write code to handle the mouse and keyboard such that
they behave correctly, I can't develop a nice user interface...