>If you use one of those methods, remember that absent any difference
>between the PICs, each PIC will generate the same random numbers,
>thereby preventing the ID-allocation method from working.

Since good pseudo-random number generators produce widely varying outputs
depending upon small differences in seed values (much like CRC's do -
hint-hint), even a small difference in the oscillator speed will generate
sufficient randomness.

Even small differences between ceramic resonators and/or crystals should
help somewhat.

>So... You need some differences between the PICs.  The easiest way is
>to put a low-accuracy RC on each PIC's MCLR line or -- if the PICs
>don't need to have accurate timing for anything else they're doing --
>to clock the PICs with RC oscillators rather than crystals or ceramic
>resonators.

Another place to put the RC value would be the RA4/TMR0 input pin.

Absolute homogeneity is a pain.

The other Andy

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Andy Kunz - Montana Design - 409 S 6th St - Phillipsburg, NJ 08865
          Hardware & Software for Industry & R/C Hobbies
        "Go fast, turn right, and keep the wet side down!"
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