Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!cs.utexas.edu!ut-emx!dak
From: dak@ut-emx.UUCP (Donald A Kassebaum)
Newsgroups: comp.sys.cbm
Subject: Re: Faster IEEE-488 devices (was Re: SEQ file access speedup)
Summary: Mc68488
Message-ID: <10553@ut-emx.UUCP>
Date: 16 Feb 89 13:59:15 GMT
References: <89Feb10.182100est.2732@godzilla.eecg.toronto.edu> <35528@tut.cis.ohio-state.edu>
Organization: The University of Texas at Austin, Austin, Texas
Lines: 16


	The older Pet and CBM computers used the old MC 488 buffers which
	handled 4 IEEE488 line, with and input and an output for each
	IEEE 488 signal.  The IEEE 488 data line input whent to half of
	a 6520, and the output line when to the other half of the 6520.
	The control lines which were used went to the 6522.  The newer
	IEEE488 buffers have a dirction pin associated with input/output.

	The mc68488 is indeed a nice chip, but it is a listener/talker.
	It is used in many Ieee488 instruments.  In order to make it a
	controler, addition hardware is required to handle ATN, SRQ, IFC,
	REN and EOI in certain cases.

	It is too bad that MC didn't see fit to add these features to the chip.

	Dak