Chapter 27 512 KByte Flash Module (S12XFTM512K3V1)
MC9S12XE-Family Reference Manual , Rev. 1.19
1060
Freescale Semiconductor
state. During the execution of this command (CCIF=0) the user must not write to any Flash module
register. The CCIF flag is set after the Unsecure Flash operation has completed.
27.4.2.12 Verify Backdoor Access Key Command
The Verify Backdoor Access Key command will only execute if it is enabled by the KEYEN bits in the
FSEC register (see
). The Verify Backdoor Access Key command releases security if user-
supplied keys match those stored in the Flash security bytes of the Flash configuration field (see
).
Upon clearing CCIF to launch the Verify Backdoor Access Key command, the Memory Controller will
check the FSEC KEYEN bits to verify that this command is enabled. If not enabled, the Memory
Controller sets the ACCERR bit in the FSTAT register and terminates. If the command is enabled, the
Memory Controller compares the key provided in FCCOB to the backdoor comparison key in the Flash
configuration field. If the backdoor keys match, security will be released. If the backdoor keys do not
match, security is not released and all future attempts to execute the Verify Backdoor Access Key
command are aborted (set ACCERR) until a power down reset occurs. The CCIF flag is set after the Verify
Backdoor Access Key operation has completed.
Table 27-54. Unsecure Flash Command Error Handling
Register
Error Bit
Error Condition
FSTAT
ACCERR
Set if CCOBIX[2:0] != 000 at command launch
Set if a Load Data Field command sequence is currently active
Set if command not available in current mode (see
)
FPVIOL
Set if any area of the P-Flash memory is protected
MGSTAT1
Set if any errors have been encountered during the verify operation
MGSTAT0
Set if any non-correctable errors have been encountered during the verify
operation
FERSTAT
EPVIOLIF
Set if any area of the buffer RAM EEE partition is protected
Table 27-55. Verify Backdoor Access Key Command FCCOB Requirements
CCOBIX[2:0]
FCCOB Parameters
000
0x0C
Not required
001
Key 0
010
Key 1
011
Key 2
100
Key 3
Because
of
an
order
from
the
United
States
International
Trade
Commission,
BGA-packaged
product
lines
and
part
numbers
indicated
here
currently
are
not
available
from
Freescale
for
import
or
sale
in
the
United
States
prior
to
September
2010:
S12XE
products
in
208
MAPBGA
packages
