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Re: 40 MHz RCA COSMAC

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  • jdrose_8_bit
    Oh, I think I have to find one of those for my collection. Very cool. First I heard of it. Any idea what the RCA number was for it? +++ OT: Zilog is still
    Message 1 of 31 , May 26 12:08 PM
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      Oh, I think I have to find one of those for my collection. Very cool. First I heard of it. Any idea what the RCA number was for it?

      +++

      OT: Zilog is still around. And they have microcontroller comic books.
      Menace of the Motor Control Maggots:
      http://www.zilog.com/captain_zilog/

      --- In cosmacelf@yahoogroups.com, Lee Hart <leeahart@...> wrote:
      >
      >
      > I don't know if they were *mass* produced, but they certainly make a
      > significant number of them. I remember our RCA rep coming around with
      > one, and looking for applications/customers. The price was something
      > like $100 each, so we didn't buy any.
      >
      > So my guess is that they never found enough customers willing to pay the
      > higher price for the extra speed.
      > --
      > Don't worry about people stealing your ideas. If your ideas are any
      > good, you'll have to ram them down people's throats. -- Howard Aiken
      > --
      > Lee A. Hart, http://www.sunrise-ev.com/LeesEVs.htm
      >
    • Andrew Wasson
      Well I was fortunate enough to just be amazed and happy that I didn t fry my 1802 chips back in the day (late 70 s) because I tended to fry most of the other
      Message 31 of 31 , May 28 9:25 AM
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        Well I was fortunate enough to just be amazed and happy that I didn't fry my 1802 chips back in the day (late 70's) because I tended to fry most of the other chips I had as well as the FETs I was trying to use in amplifier circuits. Darn FET's… They were expensive and sensitive. I never managed to handle them without frying them; same with some of the early Op Amps. 741's were bulletproof but the RCA 3130's were pretty useless as soon as I got my clumsy, static charged hands on them.

        I think the 1802D was on the slower end of 1802's at 2.5MHz. The 1802ACE was 3.5MHz and then the 1802BCE was the fast one at 5MHz. I have a pair of BCE chips so I think I may build a little speed demon ELF with one. I'll bet someone here like Lee has info about over clocking 1802 chips although I think the value with them is going in the opposite direction and slowing the clock speed way down so that it can be run off a small battery or two. 

        I too have a bunch of chips from back in the day (circa 1979) including the radio shack 74150 that somehow survived my many hex keypad experiments. I have no idea how it survived but I pulled it out of retirement a few weeks ago and sure enough it's still going strong. I'll have to take inventory one of these days and catalogue all of my vintage electronic components. 

        Andrew 



        On 2013-05-28, at 2:50 AM, Mark Graybill <saundby@...> wrote:

         

        I was using 1802Ds. I did the experiments in late '77 to early '78 as I recall. I felt flush from a new job on top of my paper route and 7-Eleven income, so I bought a bunch of chips in fall '77. Then I fried a bunch during school breaks.

        I still have and use ICs from that buying spree, but unfortunately not 1802s, my current stock of those is much newer. And I have no interest in overclocking any more. ;)

        Here I have a drawer full of 8755s and no programmer that will handle them now. I should have bought one then, but back then I built up ad-hoc programming circuits on a bread board. Anyone know a current hobby-cost programmer that'll do it? Nowadays, the more time it takes to complete a project, the higher the chances something will shoulder it aside before completion.

        Mark, W8BIT

        On May 27, 2013 11:22 PM, "Andrew Wasson" <awasson@...> wrote:
         

        Mark, were you using the 1802ACE or the 1802BCE.


        As I understand it the ACE would run at 3.2MHz at 5 volts but the BCE would run at 5MHz. I'm not sure how high you can run the voltage with them but you would certainly do better with a BCE in your over clocking projects.

        Andrew 






        On 2013-05-27, at 10:03 PM, Mark Graybill <saundby@...> wrote:

         

        Then we just need to scour the surplus yards for ICBM warhead buses (sans warheads, hopefully), and take our handy Civil Defense radiation counter with us. :D


        I used to push ceramic 1802s pretty hard to see what I could do with them (did myself out of a _lot_ of chips that way, experimenting and continuing to think that I _almost_ had it last time when the chip went dead.) I remember running them up to 15 or 18V and at least momentarily getting speeds around 10-14MHz.

        I monkeyed around with Vcc, Vdd, and clock in various ways trying to find the "magic" combination. Then one day I realized how much I'd spent on all the chips I'd fried in those late-night marathons trying to create a speed demon...

        If I'd had more of a clue at the time, I might have been able to get one stable at about 10MHz, but I knew nothing about, for example, heat sinking DIP ICs (I got the idea with cans--transistors and op amps--but anything else, I had a blind spot.)

        Still, it was educational. If for no reason other than when I learned something later I was able to look back and say, "I wish I'd known that before I fried all those 1802s!"

        Mark Graybill---------------------------------------------------------------
        Electronics, Books, Video Games, etc.

        On May 27, 2013, at 2:54 PM, Lee Hart wrote:

         

        On 5/27/2013 3:52 PM, Kent Andersen wrote:
        > Thanks for the information Lee, do you happen to know what pieces of
        > equipment were built with the SOS 1802?

        Sorry; I have no idea. I don't know if RCA ever found *any* customers
        for the SOS 1802. But since it was fast, low power, naturally radiation
        resistant, and expensive, I would guess it would have been in some
        military or NASA equipment.

        --
        If you want to build a ship, don't drum up people to collect wood
        and don't assign them tasks and work. Rather, teach them to long
        for the endless immensity of the sea. -- Antoine de Saint-Exupery
        --
        Lee A. Hart, http://www.sunrise-ev.com/LeesEVs.htm







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