Chapter 19 Flash Module (S12ZFTMRZ)MC9S12ZVMB Family Reference Manual Rev. 1.3664 NXP SemiconductorsIf the comparison key successfully matches the key programmed in the Flash Configuration Field theProtection Override command will preserve the current values of registers FPROT and DFPROT stored inan internal area and will override these registers as selected by the Protection Update Selection field withthe value(s) loaded on FCCOB parameters. The new values loaded into FPROT and/or DFPROT canreconfigure protection without any restriction (by increasing, decreasing or disabling protection limits). Ifthe command executes successfully the FPSTAT FPOVRD bit will set.If the comparison key does not match the key programmed in the Flash Configuration Field, or if the keyloaded on FCCOB is 16’hFFFF, the value of registers FPROT and DFPROT will be restored to theiroriginal contents before executing the Protection Override command and the FPSTAT FPOVRD bit willbe cleared. If the contents of the Protection Override Comparison Key in the Flash Configuration Field isleft in the erased state (i.e. 16’hFFFF) the Protection Override feature is permanently disabled. If thecommand execution is flagged as an error (ACCERR being set for incorrect command launch) the valuesof FPROT and DFPROT will not be modified.The Protection Override command can be called multiple times and every time it is launched it willpreserve the current values of registers FPROT and DFPROT in a single-entry buffer to be restored later;when the Protection Override command is launched to restore FPROT and DFPROT these registers willassume the values they had before executing the Protection Override command on the last time. If contentsof FPROT and/or DFPROT registers were modified by direct register writes while protection is overriddenthese modifications will be lost. Running Protection Override command to restore the contents of registersFPROT and DFPROT will not force them to the reset values.Table 19-69. Protection Override selection descriptionProtection UpdateSelection code [1:0] Protection register selectionbit 0Update P-Flash protection0 - keep unchanged (do not update)1 - update P-Flash protection with new FPROT value loaded on FCCOBbit 1Update EEPROM protection0 - keep unchanged (do not update)1 - update EEPROM protection with new DFPROT value loaded on FCCOB
