Ron Anthony [mailto:ronant@OPTONLINE.NET] wrote:

> Hello all, who else uses the 16F877?  Who else is totally
> disgusted that the
> 77A revision is delayed until next March at the earliest???
> The 77 is a
> flash chip that if you leave it flash upgradable, you must leave it
> completely NAKED for copying.  Is this as ridiculous as I
> think it is?  If
> you code protect the flash it becomes OTP memory that can
> never be updated
> without wiping out the entire chip, which means your
> bootloader code is GONE
> and can't be used to update the flash.

I've written a new app. Running in embedded environment and many identical
devices on one bus,
i wanted to include a bootloader. Same questions for me.
Using the bootloader approach, i must leave the chip unprotected (upper 256
words protected).
Happy reverse-engineering !!!!
I have read the data manual for the 16F77, hoping this chip handles the
protection better. But: no opinion for system upgrade, the program memory is
only readible for program verification. This gives a little bit more
security, but no more support in the field. So the only solution was and is
to use the 'F87X.
I'm very disappointed.

> The 77A revision is much more secure.  You
> can, supposedly, disable in circuit serial programming, and
> can also disable interal flash reads.

I have not read the data manual. What is the background for disabling
internal flash read. It makes no sense for me.

> The chip is secure, the only liability being someone
> watching your comms when you update by way of the bootloader.

Does this mean, that the chip can update his program memory while it is
protected against reading via ICSP ? If so, then there are no more problems.
I must read the manual...

Frank

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