Datasheet
Chapter 2 256 Kbyte Flash Module (S12FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.10
92 Freescale Semiconductor
2.3.2.5 Flash Protection Register (FPROT)
The banked FPROT register defines which Flash sectors are protected against program or erase operations.
All bits in the FPROT register are readable and writable with restrictions except for RNV[6] which is only
readable (see Section 2.3.2.6, “Flash Protection Restrictions”).
During reset, the banked FPROT registers are loaded from the Flash Configuration Field at the address
shown in Table 2-11. To change the Flash protection that will be loaded during the reset sequence, the
upper sector of the Flash memory must be unprotected, then the Flash Protect/Security byte located as
described in Table 2-2 must be reprogrammed.
Table 2-10. FCNFG Field Descriptions
Field Description
7
CBEIE
Command Buffer Empty Interrupt Enable — The CBEIE bit enables an interrupt in case of an empty command
buffer in the Flash module.
0 Command buffer empty interrupt disabled.
1 An interrupt will be requested whenever the CBEIF flag (see Section 2.3.2.7, “Flash Status Register (FSTAT)”)
is set.
6
CCIE
Command Complete Interrupt Enable — The CCIE bit enables an interrupt in case all commands have been
completed in the Flash module.
0 Command complete interrupt disabled.
1 An interrupt will be requested whenever the CCIF flag (see Section 2.3.2.7, “Flash Status Register (FSTAT)”)
is set.
5
KEYACC
Enable Security Key Writing
0 Flash writes are interpreted as the start of a command write sequence.
1 Writes to Flash array are interpreted as keys to open the backdoor. Reads of the Flash array return invalid
data.
0
BKSEL
Block Select — The BKSEL bit indicates which register bank is active.
0 Select register bank associated with Flash block 0.
1 Select register bank associated with Flash block 1.
Module Base + 0x0004
76543210
R
FPOPEN
RNV6
FPHDIS FPHS FPLDIS FPLS
W
Reset F F FFFFFF
= Unimplemented or Reserved
Figure 2-8. Flash Protection Register (FPROT)
Table 2-11. Reset Loading of FPROT
Flash Address Protection Byte for
0xFF0D Flash Block 0
0xFF0C Flash Block 1