program flash memory or less, FPROT0 is not used. For configurations with 16 KB ofprogram flash memory or less, FPROT1 is not used. For configurations with 8 KB ofprogram flash memory, FPROT2 is not used. The bitfields are defined in each register asfollows:Program flash protection register Program flash protection bitsFPROT0 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 theprogram flash protection bytes in the Flash Configuration Field as indicated in thefollowing table.Program flash protection register Flash Configuration Field offset addressFPROT0 0x000BFPROT1 0x000AFPROT2 0x0009FPROT3 0x0008To change the program flash protection that is loaded during the reset sequence,unprotect the sector of program flash memory that contains the Flash ConfigurationField. Then, reprogram the program flash protection byte.Address: 4002_0000h base + 10h offset + (1d × i), where i=0d to 3dBit 7 6 5 4 3 2 1 0Read PROTWriteReset x* x* x* x* x* x* x* x** Notes:x = Undefined at reset.•FTFA_FPROTn field descriptionsField DescriptionPROT Program Flash Region ProtectEach program flash region can be protected from program and erase operations by setting the associatedPROT bit.In NVM Normal mode: The protection can only be increased, meaning that currently unprotected memorycan be protected, but currently protected memory cannot be unprotected. Since unprotected regions aremarked with a 1 and protected regions use a 0, only writes changing 1s to 0s are accepted. This 1-to-0transition check is performed on a bit-by-bit basis. Those FPROT bits with 1-to-0 transitions are acceptedwhile all bits with 0-to-1 transitions are ignored.Memory Map and RegistersKL27 Sub-Family Reference Manual , Rev. 5, 01/2016900 Freescale Semiconductor, Inc.
