Hi All ,
How do you know that the controller is protected ?
I have red a Pic controller and the programmer doesn't give me any
message and the output file was not FF's or 0's NO it have a data !!!
When i tried to program similar controller with this file it doesn't work .
that means the data i have red was not correct .. I retried to read
another one ; i had the same checksum ..
I thought that when i try to read a locked controller either the
programmer will fail or i will got an FF or 0's file . Am I right ? Does any
body face this before ?
Maybe this can help you:
I checked with two code protected PIC's (16F628, 16F877).
When you read them back you only get 0x00 instead of the programmed data, you can read back the ID locations (at 0x2000 to 0x2003) and the configuration word (at 0x2007).
If I remember correct a 16F84 could read back each second byte of data but the other byte was alwas 0x00 (but each instruction is composed of two bytes of data) ...
Some uC have a few bites for protection of code. In that case protection is for some parts of code not for all, so you can choose which part of code you want to protect.
In PIC's case if protection is on you read 00 on all PIC's I work with.
I'd assume that it's not code protected because the first 0x80 bytes (= 0x40 words of totally 0x200 usable words) are too different; also the 16C55 can't be protected partly. But you didn't read the configuration word @ 0x2007 which include the protection bits....