NXP Semiconductors MC9S12VRP64, Owner Reference Manual

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64 KByte Flash Module (S12FTMRG64K4KV2)
MC9S12VRP Family Reference Manual Rev. 1.3
454 NXP Semiconductors
18.3.2.9 P-Flash Protection Register (FPROT)
The FPROT register defines which P-Flash sectors are protected against program and erase operations.
The (unreserved) bits of the FPROT register are writable in Normal Single Chip Mode with the restriction
that the size of the protected region can only be increased (see
Section 18.3.2.9.1, “P-Flash Protection
Restrictions , ” and Table 18-21 ).All (unreserved) bits of the FPROT register are writable without
restriction in Special Single Chip Mode.
During the reset sequence, the FPROT register is loaded with the contents of the P-Flash protection byte
in the Flash configuration field at global address 0x3_FF0C located in P-Flash memory (see
Table 18-4 )
as indicated by reset condition ‘F’ in Figure 18-13 . 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.
7 6 5 4 3 2 1 0
R
FPOPEN
RNV6
FPHDIS FPHS[1:0] FPLDIS FPLS[1:0]
W
Reset F
1
1
Loaded from Flash configuration field during reset sequence.
F
1
F
1
F
1
F
1
F
1
F
1
F
1
= Unimplemented or Reserved
Figure 18-13. Flash Protection Register (FPROT)
Table 18-17. 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 18-18 for the P-Flash block.
0 When FPOPEN is clear, the FPHDIS and FPLDIS bits define unprotected address ranges as specified by the
corresponding FPHS and FPLS bits
1 When FPOPEN is set, the FPHDIS and FPLDIS bits enable protection for the address range specified 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 specific region of the P-Flash memory ending with global address 0x3_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 in Table 18-19 . The FPHS bits can only be written to while the FPHDIS bit is set.