castorca@EA.USL.EDU (Christian Castor) (06/30/90)
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.
-Chris
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-------------------------------------------------------------------------------mcmahan@netcom.UUCP (Dave Mc Mahan) (07/02/90)
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
grr@cbmvax.commodore.com (George Robbins) (07/02/90)
In article <00938EEE.F9719E80@EA.USL.EDU> 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. It is widely known that the bridgeboard doesn't work with a V20, at least in a plug-n-play mode. Many PC's will, so perhaps your friend was over- generalizing or guessing. V20's have different clock requirements, so that typically you need a faster V20 than the nominal 8088 speed,also the bridgeboard may be sufficiently 8088 dependent to frustrate all efforts - dual port ram designs can be fun... -- George Robbins - now working for, uucp: {uunet|pyramid|rutgers}!cbmvax!grr but no way officially representing: domain: grr@cbmvax.commodore.com Commodore, Engineering Department phone: 215-431-9349 (only by moonlite)
castorca@EA.USL.EDU (Christian Castor) (07/03/90)
In article <11428@netcom.UUCP>, mcmahan@netcom.UUCP (Dave Mc Mahan) writes: > > 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 The following is EMail I received from eddy@duteca.tudelft.nl (Eddy Olk): (Thank you, Eddy). ] I tried this too (seeking for more speed) and it didn't work for me ] either. My bridgeboard behaved different though, it found the first ] 256K of RAM (so it forgot about the second 256K) and the screen was filled ] with random characters at random places. I think my bridgeboard behaved ] differently because I used an 8 MHz V20. Anyway it (sadly) didn't work. ] The problem is caused by a timing bug (at least I think it is) in the ] Ferranti FE-2010 chip. The chip will function OK with 8088's but will ] fail for V20's due to the slightly different timing of the V20. ] However, the Ferranti FE-2010-A (watch the A!) used in newer bridgeboards ] has no problems with the V20. So replacing the FE-2010 by a FE-2010-A will ] make the V20 work in a bridgeboard. ] BTW there are ways to speed up the bridgeboard even more. A german ] company sells upgrade sets which allow the bridgeboard to run at 8 MHz (or ] since recently even 12 MHz) with a V20. Personally I'm not seeking more ] bridgeboard performance anymore since I'm increasingly using the Amiga side ] (which has multitasking and other goodies :-). Well, it seems I'll have to go for the Ferranti chip. I've heard that the V20 will increase the Norton index from 1.0 to 1.8. What advantage does that represents in reality? I got a 30 day money back guarantee, so if this stuff is not worth, I better return it ASAP (and stick with ol' Ami 8^). Thank you all for sharing your wisdom. -Chris ------------------------------------------------------------------------------- /// Christian Castor : (318) 232-2045 (VOICE) XXXXXXX No Postage /// Compuserve: 73030,2734 X X Required \\\/// PeopleLink: Chrisc X 25c X If Mailed In \\\/ INet: castorca@ea.usl.edu XXXXXXX The US -------------------------------------------------------------------------------
alexhagn@neabbs.UUCP (ALEXANDER HAGEN) (07/11/90)
castorca@EA.USL.EDU (Christian Castor) wrote: >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? Well, nobody knows why this happens. Even Commodore doesn't know, according to a Dutch Amiga magazine. The NEC V20 seems to detekt things that aren't there. For this reason Commodore advises Amiga users against using the NEC V20 on the Bridgeboard. To bad you didn't knew about this before :-(. On the other hand, there are Bridgeboard accelerators from Germany that use the NEC V20 (8 Mhz) and some additional hardware to speed things up. ----------------------------------------------------------------------- _ Alexander Hagen | PRIV MSGS IN DUTCH, GERMAN OR ENGLISH _/_\__ Newtonstraat 20 | ````-o--o- 4532 KH Terneuzen | UUCP alexhagn@neabbs.UUCP The Netherlands | Fido 2:285/403.2 ------THE-FIRST-AND-ONLY-UNREGISTERED-AMIGA-BRIDGEBOARD-DEVELOPER------
jma@beach.cis.ufl.edu (John 'Vlad' Adams) (07/11/90)
That's funny...the 10MHz NEC V-20 in my A2088D works just fine. (Whoops, I mean my old 2088, as I sold it and am getting an HST.) -- John M. Adams --**-- Professional Student on the six-year plan! /// Internet: jma@beach.cis.ufl.edu -or- vladimir@maple.circa.ufl.edu /// "We'll always be together, together in electric dreams" Tangerine Dream \\V// Cosysop of BBS:42; Amiga BBS FIDOnet 1:3612/42. 904-438-4803 (Florida) \X/