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Chapter 23 1024 KByte Flash Module (S12XFTM1024K5V2)
MC9S12XE-Family Reference Manual , Rev. 1.07
864
Freescale Semiconductor
23.3.2.9
P-Flash Protection Register (FPROT)
The FPROT register defines which P-Flash sectors are protected against program and erase operations.
All bitsin the FPROT register are readable and writable with restrictions(see
Section 23.3.2.9.1,“P-Flash
Protection Restrictions”
) except for RNV[6] which is only readable.
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 0x7F_FF0C located in P-Flash memory (see
Table 23-3
)
as indicated by reset condition F in
Figure 23-13
. 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.
1
DFDIF
Double Bit Fault Detect Interrupt Flag
— The setting of the DFDIF flag indicates that a double bit fault was
detected in the stored parity and data bits during a Flash array read operation or that a Flash array read operation
was attempted on a Flash block that was under a Flash command operation. The DFDIF flag is cleared by writing
a 1 to DFDIF. Writing a 0 to DFDIF has no effect on DFDIF.
0 No double bit fault detected
1 Double bit fault detected or an invalid Flash array read operation attempted
0
SFDIF
Single Bit Fault Detect Interrupt Flag
— With the IGNSF bit in the FCNFG register clear, the SFDIF flag
indicates that a single bit fault was detected in the stored parity and data bits during a Flash array read operation
or that a Flash array read operation was attempted on a Flash block that was under a Flash command operation.
The SFDIF flag is cleared by writing a 1 to SFDIF. Writing a 0 to SFDIF has no effect on SFDIF.
0 No single bit fault detected
1 Single bit fault detected and corrected or an invalid Flash array read operation attempted
Offset Module Base + 0x0008
7
6
5
4
3
2
1
0
R
FPOPEN
RNV6
FPHDIS
FPHS[1:0]
FPLDIS
FPLS[1:0]
W
Reset
F
F
F
F
F
F
F
F
= Unimplemented or Reserved
Figure 23-13. Flash Protection Register (FPROT)
Table 23-17. FERSTAT Field Descriptions (continued)
Field
Description