S912XHY128F0VLM Datasheet, PDF (658/802 Pages) Freescale Semiconductor, Inc – S12 Microcontrollers

128 KByte Flash Module (S12XFTMR128K1V1)
Table 19-1). The Verify Backdoor Access Key command must not be executed from the Flash block
containing the backdoor comparison key to avoid code runaway.
Table 19-48. 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 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.
Table 19-49. Verify Backdoor Access Key Command Error Handling
Register
FSTAT
Error Bit
ACCERR
FPVIOL
MGSTAT1
MGSTAT0
Error Condition
Set if CCOBIX[2:0] != 100 at command launch
Set if an incorrect backdoor key is supplied
Set if backdoor key access has not been enabled (KEYEN[1:0] != 10, see
Section 19.2.1.2)
Set if the backdoor key has mismatched since the last reset
None
None
None
19.3.2.12 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.
Table 19-50. Set User Margin Level Command FCCOB Requirements
CCOBIX[2:0]
000
001
0x0D
FCCOB Parameters
Global address [22:16] to identify the
Flash block
Margin level setting
MC9S12XHY-Family Reference Manual, Rev. 1.01
658
Freescale Semiconductor