At 09:39 11/05/98 -0500, you wrote:
>
>I need to design a device that would allow access to a
>specific machine and measures the time the machine was in use.
>This is to be done via a keypad. Every user will have a different
>password. It must be user expandable.

...

>So, I guess my question is: Can this be done with PIC's? I have the
>premonition that I need other chip capable of communicating with
>the LAN, which one would that be? Any suggestions or recommendations
>to any of this?

I sent someone a tiny tcp/ip stack written in C a short while ago (you know
who you are!). From what you state, I don't think a low end (mid-range?)
PIC like the 16C74A would be appropriate (or a little higher end - though
I'm not familiar with the most powerful PICs I'm afraid). I would suggest a
low-end Hitachi H8/300 series. It sounds as if this system may be subject
to "but let's just add this or that" and therefore a bit more power than
perhaps the specification suggests should be added. Sometimes I use, say,
70% of a CPU's power for a job (depending on how tight the spec is), on
this one, I'd (off the top of my head - you must know far more about it
than you were able to post - politics etc) say allow 50% and certainly make
adding changes or enhancements easy.

Just my two-pen'orth (not a mis-spelling) - a quaint old English saying -
the Ameicans would say "my 2 cents" I guess..!

Regards

Adrian

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Developers of GPS satellite-based tracking systems