The 100 MHz 6502

&gt; The idea of implementing a CPU core inside an FPGA is not new, of course.<p>Indeed. I took a computer engineering class in undergrad. The capstone project was implementing from scratch a multi-pipeline RISC CPU (including the ALU and a very basic L1 cache) in Verilog that we flashed to FPGAs that we then programmed to play checkers using hand-compiled C. The FPGA was easier to flash and debug than the Spartan-6 mentioned in TFA but was significantly more expensive as well.<p>It was a brutal class, but it totally demystified computers and the whole industry in a way that made me feel like I really could understand the &quot;whole&quot; stack. Nothing scares me any more, and I no longer fear &quot;magic&quot; in software or hardware.

Leonard Tramiel once told me that the &quot;world&#x27;s record&quot; for a production 6502 was around 25Mhz before the smoke came out. This was in a lab at Commodore, and beer was probably involved (and may have been used to cool the chip).

At the Vintage Computer Fest last week Bill Mensch mentioned to the audience that no one ever hears about the 65C02 and 65C816’s use in defibrillators and pacemakers - life critical applications - unless he tells them!<p>Does anyone know of good write ups or explanations of what makes the 6502 so reliable and what competition it had in being chosen for medical applications?

Similar for the Z80...<p>There&#x27;s an FPGA soft core called nextz80 that&#x27;s supposed to do 4x more per clock cycle than a normal z80.<p><i>&quot;Works at up to 40MHZ on Spartan XC3S700AN speed grade -4) - performances similar or better than a real Z80 running at 160Mhz.&quot;</i><p><a href="https:&#x2F;&#x2F;opencores.org&#x2F;projects&#x2F;nextz80" rel="nofollow">https:&#x2F;&#x2F;opencores.org&#x2F;projects&#x2F;nextz80</a>

That idea to treat some memory regions (e.g. memory mapped IO areas) as &quot;external memory&quot; which cause the CPU to run at the system clock speed (instead of the much faster &quot;internal clock&quot;) sounds like it could also work well for (software) emulators.<p>However for &quot;highly integrated&quot; home computers like the Atari 8-bitters and C64 I guess this wouldn&#x27;t be of much use, because most games and demos depend on proper CPU timing, even when not accessing memory mapped IO regions (for instance in wait-loops to get to the right raster position before reprogramming the video output).

I have a 16Mhz Apple 8 bit computer.<p>What struck me is how lean early tools and applications really are. Many are just usable at 1 Mhz.<p>At 16, things are generally luxurious. Doing graphics, or writing, even running programs in BASIC all make sense and perform.<p>100Mhz is crazy! Frankly, one could add to the software and take advantage of the fast electronic storage available today and get real things done.<p>I wonder just what people will wnd up doing on a BBC Micro, or Apple 8 bit machine fitted with one of these.<p>I want one! Fun project.

&quot;The 65.02 MHz 6502&quot; would be a much better headline

Way back when, in the early 90s, I ported a unix 6502 C64 emulator to Macintosh (Classic of course). I used it to play ripped Rob Hubbard tunes when the printer ran out of paper.<p>It surprised the end users who’d been ignoring the original SysBeep(1) sounds the application previously used.

This is somehow super retro cool. I remember the 8032 being the most serious computer I&#x27;d seen to date. Wordpro 4+ and something called &quot;The Manager&quot; in use at my high school, plus the rebadged daisywheel printer Commodore had at the time (CBM 6400?) just had &quot;serious computer&quot; written all over them, right before the IBM PC steamrollered all of that into oblivion.<p>100MHz. The software you could run! Add a megabyte or so of full speed, pageable RAM expansion. Every computer language right up to C++ (if it works on the 8-bit Arduino it could be shoehorned into a fast 6502 - limited stack? Who cares, just do the big stack in software. Special zero page? Just use it as glorified CPU registers).<p>What&#x27;s the point really? But awesome all the same.

I was wondering how quick an emulated 6502 could go. This project claims 10GHz+ using JIT emulation: <a href="https:&#x2F;&#x2F;github.com&#x2F;scarybeasts&#x2F;beebjit" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;scarybeasts&#x2F;beebjit</a>

This got me thinking about the CPU accelerators that were available for the Apple ][ line, including the GS&#x27;s 658C16. I googled and little did I know that there&#x27;s an enthusiast community still developing for it, that&#x27;s gotten the GS is up 18 Mhz:<p><a href="https:&#x2F;&#x2F;wiki.reactivemicro.com&#x2F;TransWarp_GS" rel="nofollow">https:&#x2F;&#x2F;wiki.reactivemicro.com&#x2F;TransWarp_GS</a>

Looks like a fun project. I should get back in to FPGA tinkering. Last time I played with one was about 20 years ago. I wonder if the development environment has improved since then?

Wow... Really really well done.<p>I love people that throw themselves at a problem that has no real use but just want to master technology. Kudos!!<p>The board design is a masterpiece too. Really clean.

This is not far in concept from modern CPUs where only the core and cache run at full speed, although it might be the first 6502 implemented this way. It reminds me of the upgrade processors for 386 and 486 PCs that had a Pentium and cache in a socket-compatible format.

If that&#x27;s not enough, you could check out &quot;Clocking a 6502 simulator to 15GHz&quot; <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=22859706" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=22859706</a>

Imagine a beowulf cluster of these.

I wonder if this would be possible to run on the Xilinx Kintex-7 FPGA employed in the currently-in-dev SoM board for MNT Reform laptop[0]? I know very little about FPGAs so I don&#x27;t know if it&#x27;s easily applicable to other boards or what. I mean, I&#x27;m not saying it would be _practical_, but it would be pretty cool! haha :)<p>[0] <a href="https:&#x2F;&#x2F;www.crowdsupply.com&#x2F;mnt&#x2F;reform&#x2F;updates&#x2F;post-campaign-orders" rel="nofollow">https:&#x2F;&#x2F;www.crowdsupply.com&#x2F;mnt&#x2F;reform&#x2F;updates&#x2F;post-campaign...</a>

Finally, C64 GEOS running at acceptable speeds? That might be an interesting thing to try...

I often ponder all the work put in to make electronics execute series of instructions one by one but where it is undesirable we often lack abstraction for parallel computing. The funny part is how parallel is so &quot;easy&quot; in electronics. My gut says there has to be some simple approach we&#x27;ve all overlooked.

When diamond semiconductors get to sufficient transistor counts, I wish for an 80GHz 6502 demonstration device.

Way back in 2003 or so, we at my old company InformAsic designed a single chip transparent VPN solution for serial communication (RS-232, RS-422).<p>The control and protocol handling part of the was a modified 6502 core with a sort of MMU and single cycle zero page registers. The whole thing was clocked at 33 MHz, probably making it the fastest 6502 in production at that time. Not that we sold that many of the devices...<p>As an old c64 scener, I really enjoyed being able to code the application SW using my favorite ASM tools. Though most of the code we actually compiled from C using cc65 and then hand tuned to fit the mem constraints.<p>Today a simple Cortex M0+ MCU (with internal AES core) would be able to do what we did, and probably be smaller and require less power.

Off topic but the eZ80 supported up to 50Mhz <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Zilog_eZ80" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Zilog_eZ80</a><p>Datasheet: <a href="https:&#x2F;&#x2F;www.mouser.com&#x2F;datasheet&#x2F;2&#x2F;240&#x2F;ps0066-2584677.pdf" rel="nofollow">https:&#x2F;&#x2F;www.mouser.com&#x2F;datasheet&#x2F;2&#x2F;240&#x2F;ps0066-2584677.pdf</a><p>You can buy them still:<p><a href="https:&#x2F;&#x2F;www.mouser.com&#x2F;Semiconductors&#x2F;Embedded-Processors-Controllers&#x2F;Microprocessors-MPU&#x2F;_&#x2F;N-6hpeh?Keyword=z80&amp;FS=True" rel="nofollow">https:&#x2F;&#x2F;www.mouser.com&#x2F;Semiconductors&#x2F;Embedded-Processors-Co...</a>

&gt; same footprint and pinout as the original 6502<p>I like this idea. This may bring a new level of repairability for devices whose chips will, one day, no longer be manufactured.

The MCL65+ is also a drop-in replacement for the 6502 which uses an 800Mhz microcontroller to emulate the CPU, so it can run in cycle accurate and accelerated modes. <a href="https:&#x2F;&#x2F;microcorelabs.wordpress.com" rel="nofollow">https:&#x2F;&#x2F;microcorelabs.wordpress.com</a>

This is pretty awesome, and while it &quot;caches&quot; all of memory, it is conceivable you could just run memory cycles the old fashioned way. And while that doesn&#x27;t give you a speed bump it does give you the worlds most amazing in-circuit-emulator pod for 6502 designs.

One problem with the Atari 400&#x2F;800 computers is that they have the ability to use any part of the 64k address space as frame buffer. You might ran zero page on the FPGA and any ROM from a cartridge to get some performance boost though.

Nice. This would be fun to add to an Acorn BBC or BBC Master via its Tube interface.<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Tube_(BBC_Micro)" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Tube_(BBC_Micro)</a>

One thing is whether this can support single step. Strange but that is what we try when hacking the 6502 and some chips are specially designed to allow single stepping.

One day we&#x27;ll have these kinds of projects for the M1.

You’re pretty close to the 2A03 used in the NES, wonder if you could get that to work? I doubt the pin out is the same as the 6502 though.

If the author reads this: can you add HTTPS support for your site? :)