At 11:25 AM 12/3/96 -0700, you wrote:
>     The 711 may be programmed as if it were a 16C621 with an older
>     programmer.  The EPROM space and config word have identical
>     addressing.
>
>     -Kurt
>
CAREFULL! There is a trap here. The trap is that bit-7 on a 16c621 is a
"reserved bit" and it's programming as a '1' or '0' is unspecified." Some
programmer suppliers, including myself, take the view that the programming
state of UNSPECIFIED reserved bits mirrors the way it is masked for
checksum calculations. This assumption is force on us because the
programming specs are never complete but there is a logical pattern that
corrolates with what information is available.

(Except for the latest programming spec DS30228F where the specified
programming level for bit-6 on the 16c6x/7x is wrong! If you don't believe
me, check it against the .INC files.)

Now, On the 16C711, bit-7 is a code protect bit and if your programmer
programs it as a '0' the following nasties occur:

You can erase it on "JW" parts, ever!

The bit may be programmed before the verifying proceedure, You can't verify
it then! (This would be the case on all my programmers.)



So, Don't rush to program your 16c711 as a 16c621, check first the default
state of bit-7. '1' is ok, '0' is bad news.

As for the 16C711 being different from a 16c71, the short answer [IMMHO] is
bull! The 16C711 is upward compatible. The only differences I know of are
the extra ram locations, faster A/D (16us Vs 20uS I think) and bug fixes.
As a last minute guess, there is a compatibility issue with RAM location 7
on some cross ports but I'm not sure if it applies here. Check it and be sure.


Jim