
Chapter 25 256 KByte Flash Module (S12XFTM256K2V1)
MC9S12XE-Family Reference Manual , Rev. 1.21
910
Freescale Semiconductor
The (unreserved) bits of the FPROT register are writable with the restriction that the size of the protected
in the Flash configuration field at global address 0x7F_FF0C located in P-Flash memory (see
Table 25-3)
as indicated by reset condition ‘F’ in
Figure 25-13. To change the P-Flash protection that will be loaded
during the reset sequence, the upper sector of the P-Flash memory must be unprotected, then the P-Flash
protection byte must be reprogrammed. If a double bit fault is detected while reading the P-Flash phrase
containing the P-Flash protection byte during the reset sequence, the FPOPEN bit will be cleared and
remaining bits in the FPROT register will be set to leave the P-Flash memory fully protected.
Trying to alter data in any protected area in the P-Flash memory will result in a protection violation error
and the FPVIOL bit will be set in the FSTAT register. The block erase of a P-Flash block is not possible
if any of the P-Flash sectors contained in the same P-Flash block are protected.
Offset Module Base + 0x0008
76543210
R
FPOPEN
RNV6
FPHDIS
FPHS[1:0]
FPLDIS
FPLS[1:0]
W
Reset
F
FFFFFF
= Unimplemented or Reserved
Figure 25-13. Flash Protection Register (FPROT)
Table 25-19. FPROT Field Descriptions
Field
Description
7
FPOPEN
Flash Protection Operation Enable — The FPOPEN bit determines the protection function for program or
erase operations as shown in
Table 25-20 for the P-Flash block.
0 When FPOPEN is clear, the FPHDIS and FPLDIS bits dene unprotected address ranges as specied by the
corresponding FPHS and FPLS bits
1 When FPOPEN is set, the FPHDIS and FPLDIS bits enable protection for the address range specied by the
corresponding FPHS and FPLS bits
6
RNV[6]
Reserved Nonvolatile Bit — The RNV bit should remain in the erased state for future enhancements.
5
FPHDIS
Flash Protection Higher Address Range Disable — The FPHDIS bit determines whether there is a
protected/unprotected area in a specic region of the P-Flash memory ending with global address 0x7F_FFFF.
0 Protection/Unprotection enabled
1 Protection/Unprotection disabled
4–3
FPHS[1:0]
Flash Protection Higher Address Size — The FPHS bits determine the size of the protected/unprotected area
in P-Flash memory as shown
inTable 25-21. The FPHS 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 a specic region of the P-Flash memory beginning with global address
0x7F_8000.
0 Protection/Unprotection enabled
1 Protection/Unprotection disabled
1–0
FPLS[1:0]
Flash Protection Lower Address Size — The FPLS bits determine the size of the protected/unprotected area
in P-Flash memory as shown in
Table 25-22. The FPLS bits can only be written to while the FPLDIS bit is set.