Dynamic USB Serial Number (PIC18F4550)

[Darrel Taylor]

Sure, you could just write the PORTD value to flash on power-up (if it changed). Then when the device connects to the PC ... it will have the new S/N.

But yes ... writing the string to flash IS the hard part, and that would limit you to 256 devices (globally).

Some programmers will allow you to save an incrementing S/N to flash on each program cycle. The meLabs programmer let's you do that. But finding the correct location in flash to put the data is the hard part there. If the program changes, the string location will too.

It's a tough one.
<br>

[awmt102]

OK, I failed to realise that the location in flash will change (although it does make sense now I think about it).

Limiting to 256 devices is no problem, there will never be that many in existence.

I think what I shall do is revert to an earlier version of my firmware that uses an extra byte in the USB Transfers to identify the device.

Thanks for the help Darrel.