Will any 6502 work in a Vic?
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Will any 6502 work in a Vic?
Hi. I just received a broken Vic and by swapping the chips I've determined that the 6502 CPU is dead.
Can somebody please tell me - would any (brand of) 6502 work in a Vic?
Thanks
Can somebody please tell me - would any (brand of) 6502 work in a Vic?
Thanks
- joshuadenmark
- Big Mover
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Ive bought one at ebay, was not original but worked fine ![Very Happy :D](./images/smilies/icon_biggrin.gif)
http://www.ebay.com/sch/sis.html?_kw=1+ ... 0584473522
Ebay search
![Very Happy :D](./images/smilies/icon_biggrin.gif)
http://www.ebay.com/sch/sis.html?_kw=1+ ... 0584473522
Ebay search
Kind regards, Peter.
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Thanks Joshua. I ordered a couple from eBay lastnight. One of the auctions listed that the clone chip was compatible with CBM PET and other 8bit micros so I figured it must be OK. I'll reply to my own posting with the details once I receive the chips. I just wasn't sure if the chips were made with different types of transistors etc (e.g. TTL vs CMOS). I believe the "MOS" name of the CBM 6502 is the company but it scares me into thinkin 'CMOS technology' etc.joshuadenmark wrote:Ive bought one at ebay, was not original but worked fine
http://www.ebay.com/sch/sis.html?_kw=1+ ... 0584473522
Ebay search
- joshuadenmark
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- eslapion
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My answer to your original question is no.
I suggest you visit the western design center for advice on compatibility with different versions and manufacturer's implementation of the 6502.
Some are CMOS, some are NMOS, some support DMA, most don't.
I suggest you visit the western design center for advice on compatibility with different versions and manufacturer's implementation of the 6502.
Some are CMOS, some are NMOS, some support DMA, most don't.
Be normal.
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- The Most Noble Order of Denial
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I have to contradict this. If no illegal codes are used, all 6502 variants should work. When using my hardware debugger, I often replace the original 6502 by a WDC 65SC02 ot be able to see what is going on when the 6502 writes data to the bus.eslapion wrote:My answer to your original question is no.
And FYI: you can even use a 65816 but then you have to do a bit of soldering: http://www.baltissen.org/newhtm/02to816.htm.
Code: Select all
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- eslapion
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If used as is, the W65C02S WILL cause a short circuit on pin1.ruud wrote:I have to contradict this. If no illegal codes are used, all 6502 variants should work.eslapion wrote:My answer to your original question is no.
This variant of the processor also supports external bus control and DMA. The original 6502 does not.
Last edited by eslapion on Tue Nov 15, 2011 9:29 pm, edited 1 time in total.
Be normal.
- Mike
- Herr VC
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The CMOS variant of the 6502 fixed some bugs in the arithmetic instructions, after an ADC or SBC in decimal mode the N and V flag were unusable on the NMOS 6502 (they reflected the binary result). Furthermore, the D flag is cleared after a reset, and several page-related ideosyncracies, like missing page increments in ZP-(indirect)-indexed and indirect JMP, were fixed.GreyGhost wrote:even some of the standard opcodes act differently on different 6502's, with the setting of flags.
Nothing special to be concerned of, though. You'd avoid these cases on a NMOS 6502. Only problem might be when you'd use the fixed versions on a 65C02, and then try them on a 6502 and then ran into these cases by accident - that might give you a longer debugging session.
![Wink :wink:](./images/smilies/icon_wink.gif)
Some time ago we had a similar discussion about the usefulness of the undocumented instructions, leading to the thread '65xx Opcode statistics, an example'.RJBowman wrote:I don't know how widely used these opcodes are.
Greetings,
Michael
- joshuadenmark
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- eslapion
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The W65C02S caused problems when loading and saving data to datasette and floppy drives.SparkyNZ wrote:Hi Everybody. Just to recap on my original post.. I received my new chips yesterday. They're CM630P chips. I plugged it in and the Vic is working great again. Ran a few demos and games OK so thats good enough for me!
If these worked fine with your chips then everything should be ok.
Be normal.