Programm EEPROM MC9S12XDP512 without BDM

[admin]

Hello.
In my program it is necessary to save current customisations in EEPROM. I work with microprocessor MC9S12XDP512. Has written the program I start it in a debug mode with connected BDM modul, all perfectly works. I disable BDM modul I include the device, it passes in a state an error of operation with EEPROM. I can not understand why so occurs (((((. I think that probably occurs from for that that a normal operating mode of the microprocessor the writeprotect is installed. Read datasheet there it is written that it can be removed with the help backdoor key access, but I have not found what data series it would be necessary to write what to remove protection ((((   Prompt as to be????

[kef · Accepted solution]

If I understood you properly, EEPROM works in special mode (with BDM connected), and doesn't work in normal mode. ECLKDIV register is write-once in normal modes. Make sure your code initializes ECLKDIV using single write operation. For example setting/clearing PRDIV8 bit, then writing other ECLKDIV bits is bad and won't work in normal modes.

Backdoor access has nothing to do with write protection.

[admin]

Thanks kef, in it also there was a problem))))