Path: utzoo!attcan!uunet!aplcen!uakari.primate.wisc.edu!zaphod.mps.ohio-state.edu!usc!cs.utexas.edu!sun-barr!newstop!sun!amdahl!netcom!mcmahan
From: mcmahan@netcom.UUCP (Dave Mc Mahan)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: NEC V20 chip
Message-ID: <11428@netcom.UUCP>
Date: 1 Jul 90 22:36:10 GMT
References: <00938EEE.F9719E80@EA.USL.EDU>
Organization: Dave McMahan @ NetCom Services
Lines: 28


 In a previous article, castorca@EA.USL.EDU (Christian Castor) writes:
>
>I have an A2088 bridgeboard. Someone told me that if I took
>out the Intel 8088 chip from the BB, and replace it with
>a NEC V20 chip (5 MHz), the board would increase its 
>speed a little bit. 
>   I got two V20 chips mail order, and neither worked. When
>I plug in the V20, the BB boots, but it reports that there
>is an error in a 64K RAM address. After that, the entire
>system freezes.  When I replaced the Intel 8088, everything
>ran OK.
>Anyone knows the cause of this problem?
>(My bridgeboard has the old (1988) Janus chips and software).
>Also, I noted that the chip number of my V20s is D70108D-5, 
>while the chip number on a catalog is D70108C-5. 
>Thanx in advance.

I have been told that this is because the V20 wants to see 50% duty-cycle
clock cycles.  The bridgeboard produces about 30% duty cycles.  I have no
idea if this is the true problem or not.  My experiences with V20 chips have
been that it does speed up the computer, but nothing noticable unless you
use a program like Norton Utilities to actually measure it.


>-Chris

   -dave