NXP Semiconductors MWCT101 S Series, Reference Manual, Page: 769 / 1761

After clearing CCIF to launch the Verify Backdoor Access Key command, the FTFC
checks the FSEC[KEYEN] bits to verify that this command is enabled. If not enabled, the
FTFC sets the FSTAT[ACCERR] bit and terminates. If the command is enabled, the
FTFC compares the key provided in FCCOB to the backdoor comparison key in the Flash
Configuration Field. If the backdoor keys match, the FSEC[SEC] field is changed to the
unsecure state and security is 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
immediately aborted and the FSTAT[ACCERR] bit is (again) set to 1 until a reset of the
FTFC module occurs. If the entire 8-byte key is all zeros or all ones, the Verify Backdoor
Access Key command fails with an access error. The CCIF flag is set after the Verify
Backdoor Access Key operation completes.
Table 32-46. Verify Backdoor Access Key command error handling
Error Condition Error Bit
Command not available in current mode/security FSTAT[ACCERR]
The supplied key is all-0s or all-Fs FSTAT[ACCERR]
An incorrect backdoor key is supplied FSTAT[ACCERR]
Backdoor key access has not been enabled (see the description of the FSEC register) FSTAT[ACCERR]
This command is launched and the backdoor key has mismatched since the last reset FSTAT[ACCERR]
32.5.11.13 Erase All Blocks Unsecure command
The Erase All Blocks Unsecure operation erases all flash memory, initializes the
FlexRAM, verifies all memory contents, programs the security byte in the Flash
Configuration Field to the unsecure state, and releases MCU security.
Table 32-47. Erase All Blocks Unsecure command FCCOB requirements
FCCOB Number FCCOB Contents [7:0]
0 0x49 (ERSALLU)
After clearing CCIF to launch the Erase All Blocks Unsecure command, the FTFC erases
all program flash memory, data flash memory, data flash IFR space, emulated EEPROM
backup memory, and FlexRAM, then verifies that all are erased.
If the FTFC verifies that all flash memories and the FlexRAM were properly erased,
security is released by setting the FSEC[SEC] field to the unsecure state, the security byte
(see
Flash configuration field description ) is programmed to the unsecure state by the
Erase All Blocks Unsecure command, and the FCNFG[RAMRDY] bit is set. If the erase
or program verify fails, the FSTAT[MGSTAT0] bit is set. The CCIF flag is set after the
Erase All Blocks Unsecure operation completes.
Chapter 32 Flash Memory Module (FTFC)
MWCT101xS Series Reference Manual, Rev. 3, 07/2019
NXP Semiconductors 769