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From: higgin@cbmvax.UUCP (Paul Higginbottom SALES)
Newsgroups: comp.sys.amiga
Subject: Re: Amiga midi problems?
Message-ID: <2197@cbmvax.UUCP>
Date: Mon, 10-Aug-87 14:31:57 EDT
Article-I.D.: cbmvax.2197
Posted: Mon Aug 10 14:31:57 1987
Date-Received: Tue, 11-Aug-87 05:51:31 EDT
References: <1408@ico.UUCP> <18700010@silver>
Reply-To: higgin@cbmvax.UUCP (Paul Higginbottom SALES)
Organization: Commodore Technology, West Chester, PA
Lines: 30

In article <18700010@silver> sl122057@silver.bacs.indiana.edu writes:
$Can someone explain the details of the serial port and timers, then?

Certainly.

$1.  What is the exact relationship between the 8520's, Paula, and the port
$    on the back?  Section 8.6 in the hardware manual seems to imply that
$  you can use the port without messing with the 8520, but then Appendix
$  F seems to say that this is where the work is really done.  So is the
$  port connected to both chips, or is one just lower level than the other?

I don't have the appendixes close by, but I assure you, they're separate
but can be used together, if timing is necessary in conjunction with
serial i/o as is the case generally with midi.

I have written software which (bad boy I know) hacks directly with the
serial registers in the custom chips because I wanted complete control
over serial i/o without layers and layers of stuff in my way.  And I
assure you I didn't need to do anything to the 8520's.

$  2.  If you want to use the serial port, do you need to allocate the 8520A
$  timer A so no other task will grab it?

No.  You SHOULD use the resource allocation software to make sure you
take exclusive control of the port.

	Regards,
		Paul.

Disclaimer: I might be completely wrong!