Curious about the //C

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Posts: 161

Just out of curiousity.
Is it possible with //c to have
a 6502 processor rather than the 65C02?

Is it as simple as changing it over or
are there other things to consider. (or not even possible)

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tokabln's picture
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Re: Curious about the //C

Hi,

I'm not sure what you like to achieve... but changing from a CMOS 65C02 to the older NMOS 6502 seems to make no sense to me?
The 65C02 do have a couple of improvements and fixes the 6502 doesn't.

So the question is... why doing a change to a predecessor CPU ?

Wikipedia 6502 - 6502
Wikipedia 65C02 - 65C02

So what's your goal?

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gsmcten's picture
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Re: Curious about the //C

Wish,

I imagine that since the ROM for the IIc is set up to see a 65C02
that there might be some problems.
The instruction sets between the two might affect how the computer operates.

Steven Smile

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PINKBOY1006's picture
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Re: Curious about the //C

tokabln wrote:

Hi,

I'm not sure what you like to achieve... but changing from a CMOS 65C02 to the older NMOS 6502 seems to make no sense to me?
The 65C02 do have a couple of improvements and fixes the 6502 doesn't.

So the question is... why doing a change to a predecessor CPU ?

Wikipedia 6502 - 6502
Wikipedia 65C02 - 65C02

So what's your goal?

The 6502 was sometimes exploited by programmers, and therefore some programs that used these exploits don't work on the //c. It is a valid question though.

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Posts: 937
Re: Curious about the //C

Never thought about it in a //c. And I don't know the electrical specs of the socket in the //c. Will it handle the increased heat? In the //e the 6502 -=> 65C02 was a drop in replacement with firmware. The enhancement kit we all know and love.

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CWJ_Wilko's picture
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Re: Curious about the //C

Next time I have my //c cracked open, I might try this just to see what happens. It does have practical applications - if all you have around is a spare 6502, it would be nice to know whether it could replace a potentially defective 65C02.

For posterity, you can definitely replace a 6502 with a 65C02.

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Re: Curious about the //C

I once got a //e motherboard from a Chinese seller.

The chips were a mix of the old and enhanced chips.

The chip I know for sure that was missing was the 65C02.

The computer ran fine except when trying to run the latest version of PRODos 8 which requires a fully enhanced //e.

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Re: Curious about the //C

PinkBoy1006
That was another reason for why I did the post.

Steven
Yes. I thought about the ROMS for the enhanced //e and //c
and the reason for the 65C02. With Moustext included.

There goes another question. From what I know you cannot
run an Apple Mouse in a ][ or ][+ ? (Feel free to comment or correct)

Now this leads me into the who ProDOS situation. Up to version 2.0
can run on unehanced (native 6502) but not from there on.
I only used ProDOS in the earlier days as most of who I was with came
from DOS 3.3 and knew it well and could do alot with it. By the time
ProDOS came around the numbers of II community lessened so there
wasn't alot who kept with Apples. I know it was supposed to be
a better OS but having been so acquainted with DOS I didn't really
see the need to change (and learning a operating system).

Now that I am going back to programming (more particular in
using the //e to it's fullest in double hi-res graphics) I will
have to take this route. What's different now in ProDOS.

Well John Brooks is beta testing ProDOS 2.4 which will run
on all Apple ][ systems in native 6502. (Kind of makes me wonder
why 2.0 and onwards runs in 65C02)

Theories, comments or thoughts?

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Re: Curious about the //C

A new PRODOS? Ohh how cool..

As to why the later versions of PRODOS needed the cmos chip? I'd guess more functionality was being created and they made use of the expanded instruction set to help out?? Or maybe it was to help insure that the latest roms were in use?

Be interesting to find the true answer.

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Re: Curious about the //C

wish,

Quote:

Well John Brooks is beta testing ProDOS 2.4 which will run
on all Apple ][ systems in native 6502. (Kind of makes me wonder
why 2.0 and onwards runs in 65C02)

First I've heard of this.

Has he had any problems with the conversion?

This could be a plus for the folks using ADTPro too.

Steven Smile

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Re: Curious about the //C

How so?

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Re: Curious about the //C

I may be wrong, but I thought that
you couldn't use ProDOS on a II.

If I'm wrong let me know.

Steven Smile

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Steven (gsmcten)

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Re: Curious about the //C

John Brooks 17 Aug

Other recipients:
I built ProDOS 2.4 RC1 today and sent it to volunteers for testing. Notes on new features (1-6 are same as Beta1): 1) All ProDOS functions are now 6502 code except /RAM, 80 col quit, GS clock, & GSOS quit 2) Apple ][, ][+, and un-enhanced //e
I built ProDOS 2.4 RC1 today and sent it to volunteers for testing.

Notes on new features (1-6 are same as Beta1):
1) All ProDOS functions are now 6502 code except /RAM, 80 col quit, GS clock, & GSOS quit
2) Apple ][, ][+, and un-enhanced //e compatible
3) Fixed aux-mem test at 01/0400 which caused a flashing period on ][ & ][+
4) Greeting text and LC error text converts from lower to upper case if CPU==6502
5) Tested on emulators to run on ][+ and IIGS
6) Can be copied to system folder and renamed to P8 to use with GSOS
7) SystemDeath message system added at LC bank 2, $D001-$D04F
Cool Minor size and space optimizations to fit SysDeath + 6502 without increasing the file size

Known issues:
-none-

-JB
Twitter: @JBrooksBSI

here's the link

https://groups.google.com/forum/#!topic/comp.sys.apple2.programmer/jrrb-F2prYI