NXP Semiconductors K22F series, Reference Manual, Page: 640 / 1407

FTFA_FSEC field descriptions
Field Description
7–6
KEYEN
Backdoor Key Security Enable
Enables or disables backdoor key access to the flash memory module.
00 Backdoor key access disabled
01 Backdoor key access disabled (preferred KEYEN state to disable backdoor key access)
10 Backdoor key access enabled
11 Backdoor key access disabled
5–4
MEEN
Mass Erase Enable
Enables and disables mass erase capability of the flash memory module at all times in all NVM modes.
00 Mass erase is enabled
01 Mass erase is enabled
10 Mass erase is disabled
11 Mass erase is enabled
3–2
FSLACC
Factory Security Level Access Code
Enables or disables access to the flash memory contents during returned part failure analysis at NXP.
When SEC is secure and FSLACC is denied, access to the program flash contents is denied and any
failure analysis performed by NXP factory test must begin with a full erase to unsecure the part.
When access is granted (SEC is unsecure, or SEC is secure and FSLACC is granted), NXP factory testing
has visibility of the current flash contents. The state of the FSLACC bits is only relevant when SEC is set
to secure. When SEC is set to unsecure, the FSLACC setting does not matter.
00 NXP factory access granted
01 NXP factory access denied
10 NXP factory access denied
11 NXP factory access granted
SEC Flash Security
Defines the security state of the MCU. In the secure state, the MCU limits access to flash memory module
resources. The limitations are defined per device and are detailed in the Chip Configuration details. If the
flash memory module is unsecured using backdoor key access, SEC is forced to 10b.
00 MCU security status is secure.
01 MCU security status is secure.
10 MCU security status is unsecure. (The standard shipping condition of the flash memory module is
unsecure.)
11 MCU security status is secure.
29.3.3.4 Flash Option Register (FTFA_FOPT)
The flash option register allows the MCU to customize its operations by examining the
state of these read-only bits, which are loaded from NVM at reset. The function of the
bits is defined in the device's Chip Configuration details.
All bits in the register are read-only .
Memory Map and Registers
K22F Sub-Family Reference Manual, Rev. 4, 08/2016
640 NXP Semiconductors