Replacing a 6502 with a 65C02

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Replacing a 6502 with a 65C02

Can I swap a dead 6502 with a 65c02?

Apparently, you can on a VIC-20 by disconnecting ONE pin?

Any comments on Apple ][ and clones?

 

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Apple did just that in //e. 

Apple did just that in //e.  They changed out the ROMs with the Enhancement kit also, but the 65C02 works fine with the original ROMs.  It should work fine in a ][+ also.  I've done it before.  There are a few applications that won't work on a 65C02.  Of course there are also a few that require a 65C02.

 

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softwarejanitor wrote:  It

softwarejanitor wrote:

  It should work fine in a ][+ also. 

Don't count on it.

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All I can tell you is that it

All I can tell you is that it worked when I tried a 65C02 that had come out of a //e mobo in a ][+ mobo.  Maybe not every version of 65C02 will work, but if it works in a //e there isn't a whole lot of reason to think it won't in a ][+.

 

 

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I have done it and it DOES work, BUT

Not with all Binary programs.  You will find programs that lock up or simply not work, but Applesoft works fine from my experience.

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Sure, I said that in my first

Sure, I said that in my first reply.  "There are a few applications that won't work on a 65C02".  Anything that relies on the undocumented instructions (or bugs) in the origirnal 6502 won't work on a 65C02.  That really isn't that many programs.  Most of those won't work on an Enhanced //e either.

 

 

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That one pin business seems

That one pin business seems to relate to a W65C02S, where Pin 1 is "VPB" (Vector Pull Bus) -  on a 6502 and 65C02 pin 1 is one of two pins assigned to Vss (or Ground).  

 

So at the very least, if you drop a W65C02S into a socket made for a 6502 or 65C02, pin one will be grounded and if the processor attempts to set that pin HIGH some magic smoke may escape.

 

(As a side note  -kick in the [censored] for whoever thought adding an S was suffcient to differentiate between the two.)

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softwarejanitor wrote:All I

softwarejanitor wrote:

All I can tell you is that it worked when I tried a 65C02 that had come out of a //e mobo in a ][+ mobo.  Maybe not every version of 65C02 will work, but if it works in a //e there isn't a whole lot of reason to think it won't in a ][+

I won't contradict your personal experience, but I will say that the II and II Plus were not designed to use the 65C02. Later revisions of the motherboard are more likely to work, but earlier revision II and II Plus motherboards are not guaranteed to be compatible with the 65C02.

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The mobo I tried it in was an

The mobo I tried it in was an RFI model, circa mid 1982 if I remember right, so that's a fairly late one.  The early //e wasn't designed for the 65C02 either, most of them were retrofitted.  I think probably the biggest thing would be some versions of the 65C02, depending on who fabbed them may be more likely to work than others.  The one I used was as I recall, actually either pulled from a //e mobo or  came out of an "Enhancement Kit".  It was either a GTE or NCR made chip, I don't remember right.  It's been 30+ years...  As someone else mentioned earlier in this thread some of the later WDC produced chips may not be as compatible, but I'd heard back in the day that the Rockwell 65C02 worked for some people in a ][+. Guaranteed to work?  Maybe not...  But I think more than likely most vintage 65C02 chips will work in most ][+.

 

 

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When I tried it, the only

When I tried it, the only 65C02 I had that worked were the GTE and Rockwell. I've heard that the 65C802 worked but can't verify that.

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