WDC 65C02
Jack Tseng
Atari 8bit family and Apple II family...
Jack
Lyrical Nanoha
Yes.
-uso.
Bill Garber
"Lyrical Nanoha" <Lyrica...@dosius.ath.cx> wrote in message
news:Pine.LNX.4.62.06...@static-141-149-129-16.buff.east.verizon.net...
Yes, it is compatible electrically, and no,
the WDC is in a PLCC package.
Bill Garber
Vince Briel
> the WDC is in a PLCC package.
>
> Bill Garber
Huh? I have 40 pin DIP WDC chips. I've bought 40 pin DIP directly from WDC.
I haven't directly tested the WDC 65C02 in all II's but in a IIe it should
work just fine. I had problems getting some 65C02's to work in the IIplus. I
seem to remember RAM not liking it.
Vince
Making computers fun again
See the new AltairPC
http://www.brielcomputers.com
heuser...@freenet.de
> The WDC can fit with Atari 8bit family and Apple II family...
Apple II -> yes
Atari 8 bit -> no! (at least not as a simple replacement)
The Ataris use a modified 6502 - called 6502B. It differs in only one
feature from the normal 6502: It has a special interrupt line which the
graphics processor ("ANTIC") uses to stop the 6502 and gain DMA access
to the RAM.
The 6502B is therefore not pin-compatible. You 'd have to build extra
circuitry to add this interrupt line to a "standard" CPU like the 6502
or 65C02. And if you have to do that you may use a powerful CPU like
the 65816. (Then a plethora of other problems will arise - like system
timing. But that's another story .)
C64 -> no! (I know you didn't ask ;-)
The C64 uses a 6510 which is a 6502 with two additional registers (at
addresses $0000 and $0001) to control the memory management (disabling
the system ROMs, for example).
So its even more complicated than with the Ataris - which didn't stop
people to build accelerators, though...
bye
Marcus
Rick Cortese
>>Can MOS 6502 be replaced with WDC65C02 Microprocessor?
>>The WDC can fit with Atari 8bit family and Apple II family...
>
>
> Apple II -> yes
>
> Atari 8 bit -> no! (at least not as a simple replacement)
> The Ataris use a modified 6502 - called 6502B. It differs in only one
> feature from the normal 6502: It has a special interrupt line which the
> graphics processor ("ANTIC") uses to stop the 6502 and gain DMA access
> to the RAM.
> The 6502B is therefore not pin-compatible. You 'd have to build extra
> circuitry to add this interrupt line to a "standard" CPU like the 6502
> or 65C02. And if you have to do that you may use a powerful CPU like
> the 65816. (Then a plethora of other problems will arise - like system
> timing. But that's another story .)
Mostly right. The early Atari 800 used 6502B and the later 800s through
the XEs used a 6502C. Only the processor board for the early 6502B has
the extra circuitry you need to use a 65C02.
I have a 65C02 in one of my 800s. In my experience it does nothing but a
little power saving unless you write your own code in assembler. I seem
to recall my code was ~5% shorter using the extended instruction set.
I've got in debates with people about the value of 5% tighter code. I
think the ~5% speed gain you get is not significant but freeing up 500
bytes in the OS ROMs would allow you to add some nice features.
There was also the 65808 that is supposed to work in early 800s. This is
a 16 bit internal/65816 pin compatible with the 6502B. I tried for a
year to find one of these in every surplus shop in Silly Con Valley w/o
sucess.Maybe we could scrape together a million bucks and get WDC to
make another run.<grin>
Just a general comment to the group. Most people don't want to learn a
new language like Action! or assembler. People that don't solder don't
want to learn at this stage of their lives. What people seem to really
want is a new power supply that will let their Atari run like a gigaHz P4.
Bill Garber
"Vince Briel" <vbr...@removethisspamcamcast.net> wrote in message
news:f62dncCAOPPu9b7Z...@comcast.com...
>> Yes, it is compatible electrically, and no,
>> the WDC is in a PLCC package.
>>
>> Bill Garber
>
> Huh? I have 40 pin DIP WDC chips. I've bought 40 pin DIP directly from
> WDC.
Yeah, sorry. I don't know what I was thinking.
> I haven't directly tested the WDC 65C02 in all II's but in a IIe it should
> work just fine. I had problems getting some 65C02's to work in the IIplus.
> I seem to remember RAM not liking it.
True some work in the II+, some don't. :o)
Bill Garber
BLuRry
you wanted to upgrade the ram chips to faster ram, would that work?
Would the same go for a //e as well?
Vince Briel
> you wanted to upgrade the ram chips to faster ram, would that work?
> Would the same go for a //e as well?
>
Not sure, I never had to go any farther since Rich Dreher made the CFFA work
on a IIplus. If I remember correctly, the RAM chips actually got hot with
the C02 installed! It is entirely possible faster RAM would do the trick but
it would just be easier to find an accelerator on eBay. Why risk frying a
board.
Vince
--
Bill Garber
>> This was because of the older ram chips' response time, correct? If
>> you wanted to upgrade the ram chips to faster ram, would that work?
>> Would the same go for a //e as well?
>>
>
> Not sure, I never had to go any farther since Rich Dreher made the CFFA
> work on a IIplus. If I remember correctly, the RAM chips actually got hot
> with the C02 installed! It is entirely possible faster RAM would do the
> trick but it would just be easier to find an accelerator on eBay. Why risk
> frying a board.
Yeah, the accelerator does the trick.
I actually use my SpeedDemon in my IIe for a little
added speed. :o)
Bill Garber
Linards Ticmanis
> Can MOS 6502 be replaced with WDC65C02 Microprocessor? The WDC can fit with
> Atari 8bit family and Apple II family...
Yes and no.
You will lose compatibility with programs that use the 6502's "illegal"
opcodes. That's less of a problem with Apples since the company switched
to 65C02 by itself before too many programs with the illegal opcodes
were on the market.
For other system architectures that stayed with the NMOS 6502's longer
and/or used lots of cycle-counted raster beam racing code, the problem
gets bigger. Examples would be the Commodore and Atari computers and
consoles.
And of course there is the problem that other people mentioned already:
Those systems that use NMOS 6502 *derivatives* (such as 6502B, 6507,
6510 etc.) can't use the 65C02 chips without some extra circuitry.
--
Linards Ticmanis
PZ
65c802. You just didn't have the 16MB addressing range, but everything
else was there.
- Paul
Michael J. Mahon
>>This was because of the older ram chips' response time, correct? If
>>you wanted to upgrade the ram chips to faster ram, would that work?
>>Would the same go for a //e as well?
>>
>
>
> Not sure, I never had to go any farther since Rich Dreher made the CFFA work
> on a IIplus. If I remember correctly, the RAM chips actually got hot with
> the C02 installed! It is entirely possible faster RAM would do the trick but
> it would just be easier to find an accelerator on eBay. Why risk frying a
> board.
Of course, replacing an Apple II's processor with a faster processor
won't do anything to accelerate it.
The problem with using a 65C02 in an Apple ][+ has to do with setup and
hold time differences, and some liberties taken in the Apple II design.
-michael
Music synthesis for 8-bit Apple II's!
Home page: http://members.aol.com/MJMahon/
"The wastebasket is our most important design
tool--and it is seriously underused."
Vince Briel
II is going to speed it up. Most people don't realize the clock works
externally.