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DisengageSecurity & FlashBlock

Question asked by Jiri Petruzelka on Dec 16, 2010
Latest reply on Dec 17, 2010 by Jiri Petruzelka


I'd like to ask... we have a school project and I'm rather webdeveloper so please pardon my great noobness


We are to create subroutines for manipulating with flash (erase, program...). The ones I have issues with are


1) Disengage flash security

So I follow the 3-step way from manual page 58. However it says that I can write the code only from RAM, but it seems to me the only instruction, that can write to 16bit address ($FFB0-7) is STA/STHX ... which I'd guess to be located among D/H-page registers -> so it seems impossible to solve it


2) Flash Block protection

"FPROT cannot be changed directly from application software" + "protected, NVPROT is itself protected and cannot be
altered by the application software"

It again seems impossible ... there's a background regime mentioned, but I thought it's only operated by debug soft and not the program I load into flash


(the task description does not state any more details/hints)

The installed version in school is CW 5.9.0, project is Full Chip Simulation, MC9S08JM60


Could anyone point me in the right direction?


Thank you very much!