MC9S12HY64 Datasheet, PDF (553/792 Pages) Freescale Semiconductor, Inc – S12 Microcontrollers

32 KByte Flash Module (S12FTMRC32K1V1)
Table 15-50. Unsecure Flash Command Error Handling
Register
Error Bit
Error Condition
ACCERR
Set if CCOBIX[2:0] != 000 at command launch
Set if command not available in current mode (see Table 15-27)
FSTAT
FPVIOL
MGSTAT1
Set if any area of the P-Flash or D-Flash memory is protected
Set if any errors have been encountered during the verify operation¹
MGSTAT0
Set if any non-correctable errors have been encountered during the verify
operation¹
1 _{As found in the memory map for FTMRC64K1.}
15.4.5.11 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 Table 15-9). 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
Table 15-3). The Verify Backdoor Access Key command must not be executed from the Flash block
containing the backdoor comparison key to avoid code runaway.
Table 15-51. Verify Backdoor Access Key Command FCCOB Requirements
CCOBIX[2:0]
000
001
010
011
100
FCCOB Parameters
0x0C
Key 0
Key 1
Key 2
Key 3
Not required
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 with Key 0 compared to 0x3_FF00, etc. 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 reset occurs. The CCIF flag is
set after the Verify Backdoor Access Key operation has completed.
MC9S12HY/HA-Family Reference Manual, Rev. 1.04
Freescale Semiconductor
553