Random outcome on multiple devices

[Darrel Taylor]

I think this would be the same as giving the PIC a fixed seed in the code.

Exactly!
Using the U2's incrementing serial number ... Each PIC has a "Fixed Seed".
But each of the 32 PICs are guaranteed to have a different seed, therefore a different blink pattern on power-up.

They are all running the same sequence of 65535 pseudo random numbers, but they all start at a different point in that sequence.

[Aussie Barry]

Thanks for the sanity check guys
Glad to know I am on the right track.

I should be able to sort out the serial number start and incremental values but I am curious to know the best place to store the information in flash memory.
I will be totally honest - I am now working well beyond the limits of my knowledge base. A simple recommendation would be appreciated. A recommendation along with an explanation as to why would superb. I revel in every opportunity to learn something along the way.

Please note: I have RTFM. Reading is one thing, comprehending is something altogether different.

Cheers
Barry
VK2XBP

[Darrel Taylor]

I would suggest putting it at the end of Program Memory.

The 1503 has 2K words of flash, so two locations starting at 07FEh.
It will store the lowbyte and highbyte separately.

Temp   VAR WORD
Seed   VAR WORD

READCODE $7FE, Temp
Seed.LowByte = Temp.LowByte
READCODE $7FF, Temp
Seed.HighByte = Temp.LowByte

I don't have access to a 1503 today, but I think it should work.

[Aussie Barry]

Legendary response Darrel - thank you!

I will keep you posted with project milestones as they are reached.

Cheers
Barry
VK2XBP