Visual Guide to 65xx CPU Timing | Hacker News Reader

Visual Guide to 65xx CPU Timing

laughtonelectronics.com

56 pointscmrdporcupine12 comments

ARM was able to beat the 386 using similar principles, I think the ARM CPU itself was designed with DRAM timing in mind: http://www.realworldtech.com/forum/?threadid=144991&curposti...

Yeah if you go back and compare an 8mhz ARMv2 in the Archimedes machines with equivalent code in an Atari ST or Amiga, the ARM wins handily. Of course the Amiga had the advantage with custom graphics hardware for certain workflows. But the 68k is not as cycle efficient as the ARM.

There's a bit about this in Sophie Wilson's Computer History Museum interview: http://www.computerhistory.org/collections/catalog/102746190

See p21, but it's interesting throughout.

Thanks this is a very inspiring interview.

The same person made an extended CPU based of of a 65xx that could linearly address 16MB of ram. Here's a great picture of the back of the CPU board; a beautiful example of wire-wrap:

http://laughtonelectronics.com/Arcana/KimKlone/KK%200800%20f...

NB: This is not a 65C816! It's a 6502 with a very unusual memory mapper. :)

Right -- not a 65c816. There's a summary and block diagram here: http://laughtonelectronics.com/Arcana/KimKlone/Kimklone_shor...

I'm the builder! :o)

-- Jeff

The KimKlone impresses me quite a bit; was it just a case of a thought like: "oh, if I did this and this, I could extend the address space..." and then a burning desire to see it work, or did something else motivate this?

I was in my twenties, I was hugely turned on by the electronics I was learning, and I was bursting with creativity! There's a little bit of Back Story explained here, especially the "my KIM" section at the bottom of the page. http://laughtonelectronics.com/Arcana/KimKlone/BrideOfSon%20...

Also I'm a Forth fan, and when when I realized the counter/timer of a 6522 could be tricked into serving as IP for a 9-cycle machine-code NEXT instruction, the idea amused me immoderately (LMFAO) and I had to build the darn thing! :oD Previous HN thread here: https://news.ycombinator.com/item?id=3070169

Have you ever considered making a PCB of the thing and making it available to others? Hell, I wonder if it'd even be possible to make an expansion model for old 6502 machines using this technique.

It's very clever. Thank you.

Thank you for posting. A PCB would be fun but I'd be inclined to do a shrink, moving away from all the jelly-bean logic. I'm pretty sure a KimKlone clone (!) could be done with just a 128 macrocell CPLD, a '574 and the 2 uCode EPROMs, plus the VIA, the CPU, and the stock memory complement (RAM/ROM).

Do you ever visit the forum at 6502.org? There's a smallish discussion about KK there... http://forum.6502.org/viewtopic.php?f=9&t=1487

I do visit, but hadn't seen this thread. Sorting through it.

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