Re: Vertical BLanking (VBL) for Apple II

Newsgroups	comp.sys.apple2
Date	2015-01-02 17:40 -0800
References	<mmphosis-1420157056@macgui.com>
Message-ID	<c4c09601-5fda-4f1b-bfb4-4c75a76dc5a9@googlegroups.com> (permalink)
Subject	Re: Vertical BLanking (VBL) for Apple II
From	David Schmenk <dschmenk@gmail.com>

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On Thursday, 1 January 2015 16:04:20 UTC-8, mmphosis  wrote:
> http://hoop-la.ca/apple2/2015/vbl/

This is basically the code the MouseCard uses to initialize the 6522 timer for VLB interrupts on an Apple ][ and ][+. Don't try enabling the VLB interrupts from code residing in the $2000 to $4000 range, like in a ProDOS system program. Ask me how I know :-)

Dave...

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Thread

Vertical BLanking (VBL) for Apple II mmphosis <mmphosis@macgui.com> - 2015-01-02 00:03 +0000
  Re: Vertical BLanking (VBL) for Apple II "Bill Buckels" <bbuckels@mts.net> - 2015-01-01 18:10 -0600
    Re: Vertical BLanking (VBL) for Apple II doug.dingus@gmail.com - 2015-01-01 18:32 -0800
      Re: Vertical BLanking (VBL) for Apple II Michael Black <et472@ncf.ca> - 2015-01-02 00:07 -0500
        Re: Vertical BLanking (VBL) for Apple II Michael J. Mahon <mjmahon@aol.com> - 2015-01-02 02:43 -0600
  Re: Vertical BLanking (VBL) for Apple II David Schmenk <dschmenk@gmail.com> - 2015-01-02 17:40 -0800
    Re: Vertical BLanking (VBL) for Apple II D Finnigan <dog_cow@macgui.com> - 2015-01-03 07:34 +0000
    Re: Vertical BLanking (VBL) for Apple II mmphosis <mmphosis@macgui.com> - 2015-02-01 18:56 +0000

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