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6502 Relaunched... Can it be used in our 8-bits?


bbking67

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http://www.h-online....or-1422007.html

 

Can the new 14MHz 6502 be used in an Atari? Would it work? What would be needed to make it work?

 

Sounds pretty cool to me.

 

If clocked at 1.79Mhz and fed the correct voltage as it is apt to be a CMOS part, it would probably work for the most part. There are programs out there that make use of undocumented opcodes. Those may not be present or have different effects with these parts.

 

If clocked higher then some additional hardware would be required. It would have to be clocked at an even multiple of 1.79Mhz and to get any real acceleration out of it all, the RAM would have to be replaced with parts that can handle the speed. 1.79Mhz x 7 gives a clock of 12.53 Mhz which is the highest clock you can get without exceeding 14Mhz. There'd have to be some extra logic so that the support chips are only accessed 1 out of 7 clocks. DMA from ANTIC to RAM would have to likewise be divided. There would also have to be a modded OS since it no doubt has routines that are timing sensitive. Of course, a switch to make everything operate at the 1.79Mhz rate is going to be needed as well.

 

The idea of hotrodding the A8 with a fast CPU gives me a nerdgasm but it really would be a lot of work and there isn't much software that is going to run remotely correctly at such speeds. Though a slightly tweaked Blaster could be cool.

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Actually, you could take the Zip Chip approach. The Zip Chip used on board cache and ran at full speed for any cached memory location but slowed to standard speed when something wasn't in cache or to write.

8 times normal clock speed is barely over 14MHz so I'll bet it would work. You might be able to go higher if you put a heat sink on the CPU.

A lot of existing software would definitely have problems with the higher speed though.

The Apple version of the Zip Chip did have software selectable speed so new software wouldn't necessarily require the OS be rewritten.

Edited by JamesD
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Very little software has a problem when you run at 14MHZ, I assume because most timing is done with VBI (which does not change). The OS works normally with no alterations. If you leave the OS in ROM (to run at 1.79MHZ), the system seems normal as far as GR.0 screen activity is concerned.

 

The W65C02 has been around for quite a while and is not pin-compatible with the 65C02.

 

Better to use a 65C816 at 14MHZ... And, yes, you can.

 

Bob

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relaunched eh? I didn`t realize it was ever out of production.

 

In this day and age, someone could manufacture 100 6502s at 100MHz, with 64KB of RAM each, on one chip. I often wonder about this when reading about the latest GPU that has 400+ shaders and 1 billion+ transistors on the die. 6502 doesn`t have floating point or even multiplication but surely there is something cool that could be done with a billion transistors worth of them running in parallel?

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Add me to the list of nice but no thanks..

 

I use my Atari for games and very little else (some minor coding & hacking), I love it as it is, yes things like SIO2PC are wonderful add ons but the 'rush' if you like for me is booting up those old games and enjoying them as they were.

 

If I want pretty pretty I have my numerous other emulators and my Xbox360......

 

My Atari can stay as it is...

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I gaurantee that the guys who love to hack hardware still have a couple stock Atari 8-bit computers around. :) Their hobby is seeing what interesting hacks can be made. I'm all for it personally. I have many stock machines, and I have a few with various upgrades such as extra RAM and VBXE, internal MyIDE, etc... In the end, a system with a VBXE in it, is still an Atari under the covers. Same software will run, same development tools used, same 6502 code... just some extra registers to poke. ;)

 

I'd love to have a 14-Mhz atari system, just for fun.

Edited by Shawn Jefferson
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I agree... Keep it stock.

 

I don't want to change the 'feel' of the system. I want DOS 2.0 to work with no changes. I want BASIC to run out of the box.

 

When I want to address an envelope, I reach for my Atari.

 

However:

 

The envelope prints on a laser printer.

 

The BASIC program that I run boots from a CF card.

 

The CPU can run at 14MHZ and address 1MB of memory.

 

All this does not change the feel of the machine - it just extends it. If you are actually going to use your Atari as a computer, some projects become much more practical when you have extensions.

 

If you want to browse thru all the BellCom disks, for example, you can either make up the 800+ disks in the set and load them on your 1050, or mount them one-at-a-time on APE and boot each disk, or batch load them onto your CF card and boot them from there. Then there are the Atari club DOMs and ANTIC, ANALOG, and such.

 

I can play things like Wishbringer from my CF card because I can swap disks from within the Wishbringer program. All this really saves me is loading time and a minimal amount of play delay. But, it also saves my original disks and wear and tear on both them and my 1050s.

 

So, do I want a bunch of wires and soldering and such?

 

Nope.

 

Any upgrades should plug in without making a mess out of your motherboard.

 

Keep it stock.

 

Bob

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Also agree, keep it stock, the hardware we have is precious; however there is nothing saying you can't make a SBC around that new processor, making a basically whole new machine or tweaking a more common industrial something that already has it in it. Example: A Cisco 2600 series router has a 68K processor, and I wanted to make it run GEM from the ST computers. A Cisco router I don't think would ever be valuable, especially one that isn't very usable these days on the internet as it is now.

 

So get a rig that does run the new chip, mod the hell out of it and drop it in a waiting Atari shaped case, add led's, stereo sound, HDMI, hell incorporate it into a RaspberryPi, make that sucker even more interesting.

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I'd be more interested in grabbing a 6502 and strapping it to an FPGA to see what I can do regarding an 8-bit machine design of my own and investigating how that would work. For better or worse my Atari is exactly what it is and if it wasn't imperfect and limited it wouldn't hold my interest to be honest. I'd want to keep it as-is

Edited by sack-c0s
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