Freescale Semiconductor Tower System Module S12G240 TWR-S12G240 TWR-S12G240 Data Sheet

1156

Freescale Semiconductor

The FPROT register defines which P-Flash sectors are protected against program and erase operations.

The (unreserved) bits of the FPROT register are writable with the restriction that the size of the protected
region can only be increased (see

,

” and Table 31-21

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

as indicated by reset condition ‘F’ in

. 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

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 IFR Flash configuration field, during reset sequence.

F

F

F

F

= Unimplemented or Reserved

7

FPOPEN

Flash Protection Operation Enable — The FPOPEN bit determines the protection function for program or
erase operations as shown in

 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

. The FPHS bits can only be written to while the FPHDIS bit is set.