Cosmac

From: Loboyko Steve <sloboyko_at_yahoo.com>
Date: Mon Jun 17 21:34:48 2002

I think the COSMAC was one of the first micro's to be
rad-hardened, and it was thoroughly proven out
logically - that is, all of the states were provable
mathematically. I don't think that there is enough
energy in the universe to power a Pentium IV long
enough to go through every single distinct logic
state.

Interestingly, that little mars rover that was so
successful and popular with the public - I think it
used a ceramic 80C85. Obsolete, but simple and proven.



--- Ethan Dicks <erd_6502_at_yahoo.com> wrote:
>
> --- Philip Pemberton <philpem_at_dsl.pipex.com> wrote:
> > Do any of your docs say what "COSMAC" actually
> means? I was thinking
> > along the lines of "Chip On Sapphire MAChine" or
> something like that...
>
> Never thought of the origins, but that's an astute
> guess. I just
> figured it was a catchy name invented by marketing.
>
> > IIRC NASA used 1802s on some deep-space probes).
>
> Voyager I and II, and Galileo (a recycled Voyager
> spare).
>
> In addition to radiation resistance, the 1802 works
> down to 0 Hz - it
> can be statically clocked - a buddy of mine built an
> Elf in high-school
> and didn't own an oscilloscope - for debugging it,
> he used a debounced
> switch and an analog VOM. He followed along the
> timing diagram in the
> RCA docs and manually toggled it through the states
> (8 clocks per cycle,
> 2 or 3 cycles per instruction).
>
> Unlike lots of modern processors, you can have an
> arbitrary amount
> of time between clock ticks, providing for serious
> power savings
> when a spacecraft is in
> cruise-along-and-ignore-things-for-weeks
> mode. Just set an "alarm" to speed up the clock
> when an event comes
> in, or every so often, then conserve for the rest of
> the trip (the
> Voyager frame uses plutonium RTGs (radio-isotope
> thermal generators?)
> for power, so it's not like you save on the
> batteries, but the principle
> is the same - don't stress the equipment if you have
> nothing to do.
>
> The 1802 is one of my 3 favorite microprocessors.
> As everyone else has
> said, nice find.
>
> -ethan
>
>
>
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Received on Mon Jun 17 2002 - 21:34:48 BST

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