Datasheet

Chapter 2 256 Kbyte Flash Module (S12FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.10
Freescale Semiconductor 93
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 2-12. FPROT Field Descriptions
Field Description
7
FPOPEN
Protection Function Bit — The FPOPEN bit determines the protection function for program or erase as shown
in Table 2-13.
0 FPHDIS and FPLDIS bits define unprotected address ranges as specified 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 specified 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.
Table 2-13. Flash Protection Function
FPOPEN FPHDIS FPLDIS Function
1
1
For range sizes, refer to Table 2-14 and Table 2-15.
1 1 1 No Protection
1 1 0 Protected Low Range
1 0 1 Protected High Range
1 0 0 Protected High and Low Ranges
0 1 1 Full Block Protected
0 1 0 Unprotected Low Range
0 0 1 Unprotected High Range
0 0 0 Unprotected High and Low Ranges