Information

Program flash protection register Program flash protection bits
FPROT0 PROT[31:24]
FPROT1 PROT[23:16]
FPROT2 PROT[15:8]
FPROT3 PROT[7:0]
During the reset sequence, the FPROT registers are loaded with the contents of the
program flash protection bytes in the Flash Configuration Field as indicated in the
following table.
Program flash protection register Flash Configuration Field offset address
FPROT0 0x0008
FPROT1 0x0009
FPROT2 0x000A
FPROT3 0x000B
To change the program flash protection that is loaded during the reset sequence,
unprotect the sector of program flash memory that contains the Flash Configuration
Field. Then, reprogram the program flash protection byte.
Addresses: FPROT3 is 4002_0000h base + 10h offset = 4002_0010h
FPROT2 is 4002_0000h base + 11h offset = 4002_0011h
FPROT1 is 4002_0000h base + 12h offset = 4002_0012h
FPROT0 is 4002_0000h base + 13h offset = 4002_0013h
Bit 7 6 5 4 3 2 1 0
Read
PROT
Write
Reset
x* x* x* x* x* x* x* x*
* Notes:
x = Undefined at reset.•
FTFL_FPROTn field descriptions
Field Description
7–0
PROT
Program Flash Region Protect
Each program flash region can be protected from program and erase operations by setting the associated
PROT bit.
In NVM Normal mode: The protection can only be increased, meaning that currently unprotected
memory can be protected, but currently protected memory cannot be unprotected. Since unprotected
regions are marked with a 1 and protected regions use a 0, only writes changing 1s to 0s are accepted.
This 1-to-0 transition check is performed on a bit-by-bit basis. Those FPROT bits with 1-to-0 transitions
are accepted while all bits with 0-to-1 transitions are ignored .
In NVM Special mode: All bits of FPROT are writable without restriction. Unprotected areas can be
protected and protected areas can be unprotected.
Restriction: The user must never write to any FPROT register while a command is running (CCIF=0).
Chapter 28 Flash Memory Module (FTFL)
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
Freescale Semiconductor, Inc. 515