As the issue of unerasable code protection has surfaced again I have posted
this update to my list of devices that are SAFE to code protect.

Please read this carefully as it is easy to get confused with the different
pic families and  the inconsistences with the A, B and C revisions.

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Here is a list of devices that DO NOT have unerasable code protection. It
is worth remembering that these devices are not as secure as the later
revisions with unerasable code protection.

12-BIT CORE PARTS

At the time of this writing (updated March 2000) there are no 12-bit core
parts with unerasable code protection. Unlike the 14-Bit parts, the "A" and
"B" and "C" revisions have not implemented the unerasable code protection
scheme. Code protection CAN be used with these parts without too much
concern.


16C52-54-55-56-57-58
12C508-509, 12CE518-519
16C505
16HV540

(All "A" and "B" and "C" suffix parts (16C54A etc.) are included.)

14-BIT CORE PARTS

The devices listed below are 14-Bit core parts that you CAN erase the code
protection with. However, except for the 16C61 and 16C71, the code
protection bits take a l-o-n-g time to erase. This could be up to several
hours. If you are in a hurry for them, don't use code protection.

16C61-62-64-65 ( "A", "B" and "C" suffix parts are NOT included in this
line!, ALL 14-bit core "A", "B" and "C"  parts ARE ALL UNERASABLE.)

16C71-73-74 ( "A", "B" and "C" suffix parts are NOT included in this line!
See above.)

NOTE! There are 16Cxx(x) parts that do not have a A, B or C suffix and are
unerasable. If you do not see a 16Cxx part named here then it has
unerasable code protection.

Of course the EEPROM/FLASH parts don't have unerasable code protection.
16C84, 16F83-84, 16F873, 874, 876, 877, 16F627, 628

The only 17Cxx or 17C75x family member without unerasable code protection
is the 17C42 without the "A" (The "A" is a UNERASABLE part)


CONCLUSION

Didn't see it listed above as not having unerasable code protection? Then
assume it has unerasable code protection.

Regards,

Jim Robertson
NEWFOUND ELECTRONICS
________________________________________
Email: newfound@pipeline.com.au
http://www.new-elect.com
MPLAB compatible PIC programmers.
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