Reverse engineering the 6502 or some people have way too much time on heir hands

Discussion in 'Embedded Systems and Microcontrollers' started by spinnaker, Dec 27, 2017.

  1. spinnaker

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    I loved the 6502. It was the first chip I learned to program on a KIM. My next two computers were 6502 based. But not sure I would want to invest thoushands of hours to bring the thing back to life.

    Here is a really amazing video about doing just that. It is a bit long, could have been a whole lot shorter but still amazing. He started losing me at the simulation section. ;)

     
  2. GopherT

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    Talk about reinventing the wheel!
     
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  3. Raymond Genovese

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    I see what you are saying, but I have to admit that I think it is a pretty cool example of reverse engineer a chip. I actually listened to the whole talk.

    ...also a 6502 fan...and still have my KIM-1....keep meaning to sell it but can't get it together to part with it...here is the 6502 from it...

    Kale Chip.jpg

    37th week of 76...it celebrated its 41st birthday this year....nice piece of history I think.
     
  4. spinnaker

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    As I mentioned, I learned on a KIM. I would love to buy it but likely could not afford it. I have seen them go for thousands.
     
  5. Raymond Genovese

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    Yep, I saw your reference.

    As far as I can remember, I bought mine in 1978-1980 time frame. Got it for $75 from a friend's brother who had worked at MOS and was said to have paid $150 for it. I was amazed....imagine a machine that does exactly what you tell it to do and only what you tell it to do - and it's mine! Still have that old Osbourne 6502 book around somewhere with duct tape holding the spine together. In retrospect, the KIM-1 came with a large amount of documentation - more than I could understand at that time. - and what a great time it was!

    Mine is a Rev B - Here it is:
    KIM1 IMG_2668c.jpg

    About a year ago, I took it out and cleaned it up and took a bunch of photographs. Then, I verified that it was still working (punched in a couple of listings from the First Book of KIM) - ran like a charm. Didn't get to testing the cassette interface.

    So I did all that with the idea of sticking it up on the Bay - maybe get 1K....but the more I played, the more nostalgic I got and couldn't pull the trigger.

    Then I thought that maybe I could write an article for AAC about it - you know retro-computing / history of computing, that sort of thing.
    @Tim YB an editor at the time, while appreciative of the "circuit porn" said...."sorry, I don't think the readers would know what you are talking about" - Sadly, I think he was right!

    Still, it was a great time.
     
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  6. spinnaker

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    I have been wanting to build a KIM. I have a bunch of 6502 chips, VIA etc. But looking at all of those data and address lines reminded me of why I keep putting it off.

    What is the circuity on the lower right? If memory serves, that is the power supply?

    $75 what a deal! We had a bunch at school. It would not surprise me if they weren't all thrown out . :(
     
  7. Raymond Genovese

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    Power supply was completely external (as I remember) - it was the first power supply I built (from a schematic in the manual) and I would be too embarrassed to show a picture but I still have it. I upgraded to this one, which at the time, was pretty dang professional!

    KIM Power Supply IMG_2739.jpg

    BTW: There are some very nice designs for KIM-1 work-a-likes. Seems that the 6530s are the biggest problem to get around.

    Edited to add: I think you might be pointing to the cassette interface - a marvel at the time. You could load 1K in under 3 minutes! Frequency shift keyed phase locked loop. Another guy came around and managed to cut the duration of both frequencies and you had Hypertape! Now, why didn't I see that? :)
     
    Last edited: Dec 27, 2017
  8. bertus

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  9. spinnaker

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    Yes I am aware thanks. There seems to be a very active user group too.
     
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