Ron Anthony wrote:
>The chip is 100% re-flashable after code protection only if you get your
>hands on the chip again, or recall every unit from around the world to do in
>house flash updates.  The logistics of that are so overwhelmingly
>prohibitive that it can't be done.

This applies to your situation - not everyone else works the way you do.
Every engineer has to way up the cons & pros before committing the design.

>You are presuming that I can get my hands on the chip again once it's in the
>field.  Let's assume that's possible.  Do you think I am going to receive
>envelopes mailed from around the world with chips inside, erase, reflash and
>code protect, and then mail back out to everyone?  The postage and handling
>will exceed the value of the chip.  Better yet, let's say every six months I
>re-issue a new chip.  Now I've got tens of thousands  (and more!) of
>consumers, not engineers, removing their circuit boards, using a butter
>knife to pop out the old chip, and put in the new?  One cracked socket and
>now we've got to replace the boards.  And, who is going pay for all the new
>chips?  Me?  Them?  Nobody wins except microchip, and I'll be damned if I am
>going to reward them by buying any more of this chip than I need to.  My
>only solution to preserve in-the-field-flash-upgradability and lower-half
>security is to go through the coding hell I'm going through as I write this.
>And the chip spends about 20% of its time just coping with the page flips
>(which in and of themselves are ridiculous) and as well decrypting the
>encrypted code.  And the upper half is locked OTP, the lower half is all
>naked, with half of it just jumping in and out of the upper OTP half.  Talk
>about a total freakin' MESS!!!!!!

If your product can be upgraded, then charge them for the upgrade chips.
That's exactly what other companies do. If the upgrades are to fix problems
with your product in the field, then that's another matter entirely. Yes. it
would be nice to have a protected boot-loader but that's life for now.  :-)

>Very simple:  Allow me to disable ICSP reads no matter what, and allow me to
>disable internal reads of the flash memory, but allow internal flash to be
>re-written.  So simple, they've done it now with the 77A and 18F series.
>And left me holding the bag with the miserable 77 for at least the next half
>of a year.
>
>Face it, I'm screwed.  Can't do a chip recall, it's far too
>expensive/inconvenient/ridiculous/pathetic.

Yes, you are screwed. Sorry, but I can't think of a way around it.
Regards...

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