Read P87C51

[koba30]

Hi,

I am using a TL866CSS to read a P87C51, the reading is succefull, the question is: Is this data encrypted?, can be used to programm another uC? How can I check if the code protection is activated?

Thanks in advance for you time.

[Wiljan]

I recall that a more symmetrical hex pattern normal comes when it's encrypted so I guess it's not

If you program a new chip and put into the board where the old one was and it works you know it not encrypted
Also you could try to dissemble the dump and see if it makes sense

I also recall way back the the 8751 can run with external Eprom and some guy did that an output pin did drive the input pin telling to read internal or external.
In the external Eprom he had a uart code sending data to external terminal and when start sending he flipped the pin so the dump came from internal Eprom, pretty clever 

[PCB.Wiz]

How can I check if the code protection is activated?

Save the read code to a hex file and run an 8051 disassembler on the hex file, and see if the assembler looks like gibberish...

[amyk]

A protected one will read all FF or 00; that looks like valid '51 machine code to me.

[wraper]

A protected one will read all FF or 00; that looks like valid '51 machine code to me.

ROM Encryption and read lock are two different things available in this MCU.

[greenpossum]

The first 3 bytes are the reset vector 02 0C 4F which is LJMP 0C4F. As said before, put it through a disassembler to see if the dump makes sense.