Path: utzoo!attcan!uunet!mcvax!unido!fauern!faui44!faui45!mlelstv
From: mlelstv@faui45.informatik.uni-erlangen.de (Michael van Elst )
Newsgroups: comp.sys.amiga
Subject: Re: Lucas Accelerator
Message-ID: <819@faui10.informatik.uni-erlangen.de>
Date: 23 Jan 89 16:24:28 GMT
References: <6731@louie.udel.EDU>
Organization: IMMD IV, University of Erlangen, W-Germany
Lines: 21

451061%UOTTAWA.BITNET@CORNELLC.CIT.CORNELL.EDU (Valentin Pepelea) writes:

>Now, the real subject of this message. I have built the Lucas 68020 board for
>my Amiga 1000, and are successful in loading up KS 1.1 and WB 1.1 but if I load
>instead KS 1.2 or 1.3, then the Amiga hangs up on me before showing the WB
>screen.

You don't have an 68881 ?
Since Kick1.2 the OS checks if the coprocessor is there to do additional
stuff when task switching.
This is done with a Coprocessor instruction. This instruction will never
terminate if the Coprocessor cycle isn't terminated with a DTACK.

The solution is to connect the ChipSelect with DSACK1 on the 68881.

The cycle will terminate and result in an exeception that tells
the OS that no REAL 68881 is there.

				Michael van Elst

E-mail: UUCP: ...uunet!unido!fauern!faui45!mlelstv