mc9s12xs128 Freescale Semiconductor, Inc, mc9s12xs128 Datasheet - Page 234

• Manufacturer Part Number: mc9s12xs128
• Description: Hcs12 Microcontrollers 16-bit Automotive Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Security (S12XS9SECV2)
7.1.7
Complete Memory Erase (Special Modes)
The microcontroller can be unsecured in special modes by erasing the entire EEPROM and Flash memory
contents.
When a secure microcontroller is reset into special single chip mode (SS), the BDM firmware verifies
whether the EEPROM and Flash memory are erased. If any EEPROM or Flash memory address is not
erased, only BDM hardware commands are enabled. BDM hardware commands can then be used to write
to the EEPROM and Flash registers to mass erase the EEPROM and all Flash memory blocks.
When next reset into special single chip mode, the BDM firmware will again verify whether all EEPROM
and Flash memory are erased, and this being the case, will enable all BDM commands, allowing the Flash
options/security byte to be programmed to the unsecured value. The security bits SEC[1:0] in the Flash
security register will indicate the unsecure state following the next reset.
S12XS Family Reference Manual, Rev. 1.10
234
Freescale Semiconductor