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Re: 32 Bit 1802

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  • wa9hsl
    It wasn t my intent to discourage anyone who wants to design a new 32-bit CPU from doing it but there are some real and standardized choices already out there.
    Message 1 of 36 , Sep 1, 2004
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      It wasn't my intent to discourage anyone who wants to design a new
      32-bit CPU from doing it but there are some real and standardized
      choices already out there.

      I have thought about building a multi-processor system like Richard
      suggests for some time but haven't yet built up enough steam to put
      the ideas into a real project. RCA made several nice little cmos
      controller chips (besides the 1861) and one could build such a system
      easily using them.

      The RCA chips are a little difficult to find these days but other
      chips such as the 6845 can still be easily found. The 6845 could be
      driven by an 1802 using it's own memory space and communicating with
      the main processor via a parallel port as Richard also suggests.

      The same concept could be followed for other important major functions
      such as a floppy or IDE I/O controller and even bit level I/O for
      control functions all using thier own 1802s or other micros.

      By preserving the 65k memory space of the main CPU(s) one leaves a lot
      of possibilies open. Parallel processing anyone? It is easy to forget
      just how much one can do with 65k or less of memory and I for one have
      not yet written applications on 8-bit machines that have used it all up.

      It's an entirely different story when you start to talk about object
      oriented compilers and the like. It's not uncommon to see megabyte
      sized compiles to perform fairly simple functions. That's when the
      programming and hardware details get to be more work than fun.

      al
      ....

      >
      > But If your main concern, is the graphic ability.
      > I have a suggestion. Write Code To operate some graphics card.
      > with the assumtion that it would be connected to the 1802 using 2 I/O
      > ports, the High 8 bits would just be put in a buffer chip, and when
      > the low 8 bits was writen it would then write to a 16 bit card.
      > Most of the fancy graphics we see now days is not comeing from the
      > main processor, they are comeing from the graphics processor. You
      > would then have access to the graphics memory through the interface.
      > You would then start by writeing your own graphics bios.
      > emulation would then return to emulating real hardware.
      >
      > Higher memory could also be done with just I/0 ports, to switch banks.
      >
    • 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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