Path: utzoo!mnetor!uunet!lll-winken!lll-tis!ames!umd5!uvaarpa!mcnc!gatech!hubcap!ncrcae!sauron!wfs
From: wfs@sauron.Columbia.NCR.COM (wfs)
Newsgroups: comp.sys.amiga
Subject: 68020 to 68000 adapter
Message-ID: <1060@sauron.Columbia.NCR.COM>
Date: 22 Apr 88 12:28:59 GMT
Organization: Entry Level Systems Development, NCR Corp., Columbia, SC
Lines: 28



I recently borrowed a 68020 to 68000 adapter to try out in my 2000 but failed 
to get it to work.  The 2000 began its powerup sequence (3 flashing screens) 
but failed to proceed any further than that.  

The board is made by TORCH computers for CSA and plugs directly into the 
68000 slot.  On board are 68020 and 68881 sockets, 2 pals and 3 other chips 
( 1 piggyback ).  The clock speed remains at the system speed of 7.14 MHz.

I was wondering if anybody has had experience with this board or similar 
boards and what a person must do (i.e. system eprom modification???) to get
a 68020 adapter like this to work.  

My thoughts of the problems offhand are that a system instruction for the 
68000 is being executed and interpreted by the 68020 as garbage.  This, to 
me, would be a relatively simple fix.  My other thought is that after the 
three screens flash during startup, the DMA controllers begin to kick in and
are interfering with the 68020's instruction stream.  

Any thoughts on this subject would be much appreciated.  

BTW, I do have tools such as 68020 logic analyzer, scope, and NCR Towers at 
my disposal and am willing to get my hands dirty ( so to speak ).

        Bill Stonecypher
	NCR Corporation
	
	wfs@ncrcae.Columbia.NCR.COM