Datasheet
Chapter 27 512 KByte Flash Module (S12XFTM512K3V1)
MC9S12XE-Family Reference Manual Rev. 1.25
Freescale Semiconductor 1061
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 0x7F_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.
27.4.2.13 Set User Margin Level Command
The Set User Margin Level command causes the Memory Controller to set the margin level for future read
operations of a specific P-Flash or D-Flash block.
Upon clearing CCIF to launch the Set User Margin Level command, the Memory Controller will set the
user margin level for the targeted block and then set the CCIF flag.
Valid margin level settings for the Set User Margin Level command are defined in Table 27-58.
Table 27-56. Verify Backdoor Access Key Command Error Handling
Register Error Bit Error Condition
FSTAT
ACCERR
Set if CCOBIX[2:0] != 100 at command launch
Set if a Load Data Field command sequence is currently active
Set if an incorrect backdoor key is supplied
Set if backdoor key access has not been enabled (KEYEN[1:0] != 10, see
Section 27.3.2.2)
Set if the backdoor key has mismatched since the last reset
FPVIOL None
MGSTAT1 None
MGSTAT0 None
FERSTAT EPVIOLIF None
Table 27-57. Set User Margin Level Command FCCOB Requirements
CCOBIX[2:0] FCCOB Parameters
000 0x0D
Global address [22:16] to identify the
Flash block
001 Margin level setting
Table 27-58. Valid Set User Margin Level Settings
CCOB
(CCOBIX=001)
Level Description
0x0000 Return to Normal Level
0x0001 User Margin-1 Level
(1)