3 ms·

i had a similar experience, read the Popular Electronics 8080 article but couldn't understand it. Got my hands on TI 7400 and Intel 8080 databooks and just kept

i had a similar experience, read the Popular Electronics 8080 article but couldn't understand it. Got my hands on TI 7400 and Intel 8080 databooks and just kept reading them front to back, over and over, till all the little fragments I could glean started to make sense together. Then I wire wrapped an 8080 board of my own design. (well, two of them, the first was a wiring nightmare, didn't work, so I had to start over, but I was much more skilled at that point, and my wiring was clean, and it worked right off the bat) I was most proud of noticing that on the 8080 there is some sort of halt signal pin, and a separate pause signal pin (might not have those names right, maybe it was memory ready?). Anyway, one of them detected the leading edge and the other detected the trailing edge of the clock, so I was able to rig up a pushbutton for single stepping the processor without having to figure out how to make a pushbutton debouncer circuit which I was having a lot of trouble with... good times

jacquesm 3y ago
That was quite the achievement, and - alas - one that you probably couldn't replicate today. How old were you if I may ask?
- fsckboy 3y ago
  I was 15 almost 16 when the Altair 8800 article came out in Popular Electronics, and I knew how to build little circuits using a couple transistors or a 741 op amp or 555 timer. Like I said, I could not understand the 8080 construction article, or what programming it "meant", but I knew FORTRAN and I knew programmable calculators so I guess I was coming at it from both sides. My biggest obstacle was not having any clue where to get the information I was looking for, so it would be by chance that I found out I could get databooks from chip makers. Took me a couple years all-in to build my own, but most of that time was spent reading and rereading technical manuals that I didn't quite understand. In a certain sense I was coming at it like an archeologist :) Just a few months when I got to wire wrapping. I was somewhat astonished when it worked, I thought I'd have more problems, but I did check and recheck all my work as I went because I was fearful. I had an older relative who had a job testing components (beyond plugging them in and looking at the lights he didn't know much about them) and he showed me around the lab where he worked (they were doing components for the Fidelity chess challenger) and gave me a bunch of drop-out chips that had failed the tests, including 2114(?) static ram chips and a couple of 8080s. I don't know what tests they failed, but they worked for me.
  - jacquesm 3y ago
    Wow, super cool! Thank you for the backstory, always interesting to see how people landed in this field and what made it possible. If not for a few such chance encounters my own life would have turned out entirely different.

jacquesm 3y ago

That was quite the achievement, and - alas - one that you probably couldn't replicate today. How old were you if I may ask?

fsckboy 3y ago
I was 15 almost 16 when the Altair 8800 article came out in Popular Electronics, and I knew how to build little circuits using a couple transistors or a 741 op amp or 555 timer. Like I said, I could not understand the 8080 construction article, or what programming it "meant", but I knew FORTRAN and I knew programmable calculators so I guess I was coming at it from both sides. My biggest obstacle was not having any clue where to get the information I was looking for, so it would be by chance that I found out I could get databooks from chip makers. Took me a couple years all-in to build my own, but most of that time was spent reading and rereading technical manuals that I didn't quite understand. In a certain sense I was coming at it like an archeologist :) Just a few months when I got to wire wrapping. I was somewhat astonished when it worked, I thought I'd have more problems, but I did check and recheck all my work as I went because I was fearful. I had an older relative who had a job testing components (beyond plugging them in and looking at the lights he didn't know much about them) and he showed me around the lab where he worked (they were doing components for the Fidelity chess challenger) and gave me a bunch of drop-out chips that had failed the tests, including 2114(?) static ram chips and a couple of 8080s. I don't know what tests they failed, but they worked for me.
- jacquesm 3y ago
  Wow, super cool! Thank you for the backstory, always interesting to see how people landed in this field and what made it possible. If not for a few such chance encounters my own life would have turned out entirely different.