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mytek

Overclocking the Stock 6502c: Is it Possible?

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Might be interesting to scope pin 34 and see if there is any output.

 

Yeah, I guess comparing pins 34 and 36 would be a good thing.  :)
 

So, I looked at the early CPU board schematic.   I see how the HALT works.  This won't be a problem implementing.  It's just a simple condition.

 

Edited by JimDrew
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On 6/30/2019 at 1:05 PM, CharlieChaplin said:

Bob's XL-7 was taking part in the Abbuc hardware contest 2008. Attached are the pics and other stuff which Abbuc got for the contest...

hw2008-65816cpu-speeder-bob-woolley.zip 10.98 MB · 9 downloads

 

Thanks for posting the info. Was there ever a schematic or the CPLD code released as part of this?

 

On 6/30/2019 at 1:13 PM, JimDrew said:

Yeah, I guess comparing pins 34 and 36 would be a good thing.  :)

If you look at the schematic I posted earlier, you'll see that I don't have any connection to pin 34, or even show it on the CPU component since I considered it a no-connect with anything on the die.

 

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Best Electronics has both the C014377 for $6.95. The C014806 is $8.00.

 

14377 = 6502B, 14806 = Sally.

 

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On 6/28/2019 at 9:22 AM, guus.assmann said:

Hello,

I have made a PCB, many years ago, that made it possible to use a 65C02 in the XL's or XE's.

And the XL7 is already in this forum, look at the attachments I put in.

Schematics and source code are there. Just needs some sorting out. There's "logic" in the file names.

 

BR/

Guus

 

For some reason I completely missed the schematics and the source code when you first posted this (my brain must have been stuck in a 'wait state'). Just now looking over what you uploaded, and it looks very thorough . Thanks for taking the time to upload all this great information 👍 .

 

LINK to that upload.

 

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So, I re-spun the 65xxT board to have a jumper option for pins 34 and 36 (R/W) and added pin 35 (/HLT).  So, next month I will start doing some testing with an Atari 400 or 800 to see if the halt line works correctly.

 

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22 minutes ago, JimDrew said:

So, I re-spun the 65xxT board to have a jumper option for pins 34 and 36 (R/W) and added pin 35 (/HLT).  So, next month I will start doing some testing with an Atari 400 or 800 to see if the halt line works correctly.

 

That's great news Jim 👍 . I think a lot of people will be very interested in getting something like this. Any ballpark on the cost?

 

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That project could work nicely with this:

 

 

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On 6/27/2019 at 9:55 AM, mytek said:

 

Not off topic as far as I'm concerned. Thanks for uploading 👍 .

 

I know this topic started out as an overclocking of the original Sally chip, but more and more that isn't looking to buy us much. So now it's morphed into changing processors to do acceleration, while still looking at an old school approach with the control logic, all the while attempting to keep the costs reasonable (not a lot of bells and whistles).

 

The information you provided appears to confirm what was talked about in the Atari Classics magazine article, where the 6502 is retained along with the addition of the 65816. Actually I'd just like to see a 65816 flying solo with a moderate speed up, and of course have the ability to downshift to 1.79 Mhz full time any time desired. Part of the plan would be to stick with 64K base RAM being shared, although that would be better served with higher speed static RAM. Since the 1088XEL and the soon to be released 1088XLD have fast SRAM already, that will be my initial target platform for any prototyping I'll be conducting. Please keep in mind that this is just a for fun exercise, so there might not be an end product coming out of this from my end, although the intention is to share methodology being applied in the experiments to follow.

 

 

I think it would be hilarious to use a 65816 upgrade on a disk drive... Then again, one could have a GUI load from there and use the SALLY in the Atari to still run all of the programs.

 

With all of the exotic GEOS Wheels upgrades over in C64 land, I'm surprised they haven't done that... run GEOS from an upgraded 1541/1571/1581.

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On 8/19/2019 at 12:00 AM, mytek said:

That's great news Jim 👍 . I think a lot of people will be very interested in getting something like this. Any ballpark on the cost?

 

I am thinking in the $69 range... depending on quantities, maybe less.

 

Edited by JimDrew
typo!
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On 8/18/2019 at 11:36 PM, JimDrew said:

So, I re-spun the 65xxT board to have a jumper option for pins 34 and 36 (R/W) and added pin 35 (/HLT).  So, next month I will start doing some testing with an Atari 400 or 800 to see if the halt line works correctly.

 

 

On 8/26/2019 at 3:27 PM, JimDrew said:

I am thinking in the $69 range... depending on quantities, maybe less.

 

 

Great news, Jim!!  Looking forward to the final product!!

 

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