Datasheet

FLASH Memory (FLASH)
FLASH Block Protection
MC68HC908LJ24/LK24 — Rev. 2.1 Data Sheet
Freescale Semiconductor FLASH Memory (FLASH) 77
4.8.1 FLASH Block Protect Register
The FLASH block protect register (FLBPR) is implemented as a byte
within the FLASH memory, and therefore can only be written during a
programming sequence of the FLASH memory. The value in this register
determines the starting location of the protected range within the FLASH
memory.
BPR[7:0] — FLASH Block Protect Bits
BPR[7:0] represent bits [14:7] of a 16-bit memory address. Bits
[15:14] are logic 1’s and bits [6:0] are logic 0’s.
The resultant 16-bit address is used for specifying the start address
of the FLASH memory for block protection. The FLASH is protected
from this start address to the end of FLASH memory, at $FFFF. With
this mechanism, the protect start address can be $XX00 or $XX80 (at
page boundaries — 128 bytes) within the FLASH memory.
Examples of protect start address is shown in Table 4-1:
Address: $FFCF
Bit 7654321Bit 0
Read:
BPR7 BPR6 BPR5 BPR4 BPR3 BPR2 BPR1 BPR0
Write:
Reset: Unaffected by reset; $FF when blank
Non-volatile FLASH register; write by programming.
Figure 4-4. FLASH Block Protect Register (FLBPR)
16-bit memory address
Start address of FLASH block protect 1 0000000
BPR[7:0]