>        the mains frequency might be stable in u.s. (i didn't think on this
>fact). i think it's apparent from tony's mail that he wanted an accurate
>clock. so i suggested using a high frequency crystal oscillator (about 20
>Mhz the time base of the PIC and not 32.khz etc). since the
>frequency is fairly large i don't think variations in temp. etc. will affect
>the stability of the clock. as tony'd seeked i just suggested another way of
>doing the same thing. obviously the alternative is much more expensive, which
>is the price paid for a stable clock.

32 KHz xtals are cut to be extremely accurate and stable.  That's why they
are the standard for timekeeping purposes.

A 20MHz frequency is overkill and expensive.  Let alone not usable in a '84
(which only is spec'd to 10 MHz).

Andy

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Andy Kunz - Montana Design - 409 S 6th St - Phillipsburg, NJ 08865
          Hardware & Software for Industry & R/C Hobbies
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