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Re: [cosmacelf] Re: 32 Bit 1802

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  • Jean Buchet
    ... Err... I meant a bicycle ;-) Sorry. I simply want to monitor my progress (distance, instant speed logging, average speed, altitude variations , etc). This
    Message 1 of 36 , Sep 4, 2004
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      Lee Hart a écrit :

      > Jean Buchet wrote:
      >
      >>Well, I'm thinking of building a small measure system for my bike...
      >
      >
      > This is the sort of application where the 1802 can still outperform more
      > modern chips. The battery is small, there is a lot of noise (ignition,
      > etc.), and there are temperature extremes.

      Err... I meant a bicycle ;-) Sorry.
      I simply want to monitor my progress (distance, instant speed logging,
      average speed, altitude variations , etc).

      This is a toy project for me. I'm sure I can find commercial packages,
      but this would be no fun.

      > Around 1980 I built an 1802-based datalogger. It could run for a week on
      > a 9v transistor radio battery, and 90% of that power was the A/D
      > converter. Now that we have lower-power A/D converters, you can do even
      > better.

      Are there any schematics for this ?

      kind regards,

      Jean

      --
      Jean Buchet
      jean.buchet59@...
      http://perso.libertysurf.fr/jbuchet
    • Peter de Vroomen
      ... The problem is that (CMOS Field Effect) transistors generate heat (which is nothing more than dissipating power) every time they switch from one state to
      Message 36 of 36 , Sep 6, 2004
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        > Anyway, back to earth. You don't see 32-bit ultra-low-power micros
        > because more bits means more power. To truly minimize power, you must
        > minimize clock speed and the number of transistors switching at that
        > speed. We've made another one of those monoculture decisions, and went
        > for MAXIMUM speed and MAXIMUM number of transistors.

        The problem is that (CMOS Field Effect) transistors generate heat (which is
        nothing more than dissipating power) every time they switch from one state
        to another. And more transistors means more switching going on, which means
        more power-usage.

        COSMAC stands for COmplementary MetAl-oxide Conductor (a bit of a forced
        name if you ask me :)), which was RCA's way of saying their processor was
        made with CMOD Field Effect Transistors (MOSFET's).

        If you use the bipolar transistors (instead of CMOS/NMOS Field Effect
        Transistors), you even have to keep the transistor 'in conduction' (this is
        how it's called in Dutch). If not, you won't be able to switch from one
        state to another fast enough. But a bipolar transistor in conduction also
        uses power when it's NOT switching. Which makes it even worse, although
        bipolar transistors are faster switches (if you keep them in conduction).

        Cray's used to be made of Ga-As (Gallium Arsenide) bipolar transistors. The
        computers were fast, but generated VAST amounts of heat and used as much
        power as a small town. A Cray-3 uses 88.000 watts. It ran at 500MHz, which
        is laughable these days :+). Today a P4 uses about 75 watts and runs at
        3.8GHz!

        PeterV
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