
Chapter 2 256 Kbyte ECC Flash Module (S12FTS256K2ECCV1)
MC9S12KT256 Data Sheet, Rev. 1.16
Freescale Semiconductor
85
the protection eld location during the reset sequence, the FPOPEN bit will be cleared and remaining bits
in the FPROT register will be set to leave the Flash block fully protected.
Trying to alter data in any of the protected areas in the Flash block will result in a protection violation error
and the PVIOL flag will be set in the FSTAT register. A mass erase of the Flash block is not possible if
any of the contained Flash sectors are protected.
Table 2-11. Reset Loading of FPROT
Flash Address
Protection Byte for
0xFF0D
Flash Block 0
0xFF0C
Flash Block 1
Table 2-12. FPROT Field Descriptions
Field
Description
7
FPOPEN
Protection Function Bit — The FPOPEN bit determines the protection function for program or erase as shown
0 FPHDIS and FPLDIS bits dene unprotected address ranges as specied by the corresponding FPHS[1:0]
and FPLS[1:0] bits. For an MCU without an EEPROM module, the FPOPEN clear state allows the main part
of the Flash block to be protected while a small address range can remain unprotected for EEPROM
emulation.
1 FPHDIS and FPLDIS bits enable protection for the address range specied by the corresponding FPHS[1:0]
and FPLS[1:0] bits.
6
RNV[6]
Reserved Nonvolatile Bit — The RNV[6] bit must remain in the erased state 1 for future enhancements.
5
FPHDIS
Flash Protection Higher Address Range Disable — The FPHDIS bit determines whether there is a
protected/unprotected area in the higher address space of the Flash block.
0 Protection/Unprotection enabled
1 Protection/Unprotection disabled
4:3
FPHS[1:0]
Flash Protection Higher Address Size — The FPHS[1:0] bits determine the size of the protected/unprotected
area as shown in
Table 2-14. The FPHS[1:0] bits can only be written to while the FPHDIS bit is set.
2
FPLDIS
Flash Protection Lower address range Disable — The FPLDIS bit determines whether there is a
protected/unprotected area in the lower address space of the Flash block.
0 Protection/Unprotection enabled
1 Protection/Unprotection disabled
1:0
FPLS[1:0]
Flash Protection Lower Address Size — The FPLS[1:0] bits determine the size of the protected/unprotected
area as shown in
Table 2-15. The FPLS[1:0] bits can only be written to while the FPLDIS bit is set.