FLASH Memory
FLASH Block Protect Register
MC68HC908MR16/MC68HC908MR32 — Rev. 4.0 Advance Information
MOTOROLA FLASH Memory 65
4.9 FLASH Block Protect Register
The FLASH block protect register (FLBPR) is implemented as a byte
within the FLASH memory, and therefore can be written only 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
These eight bits represent bits [14:7] of a 16-bit memory address.
Bit 15 is logic 1 and bits [6:0] are logic 0s.
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 and XX80
(128 bytes page boundaries) within the FLASH memory.
Figure 4-4. FLASH Block Protect Start Address
Refer to Table 4-1 for examples of the protect start address.
Address: $FF7E
Bit 7654321Bit 0
Read: BPR7 BPR6 BPR5 BPR4 BPR3 BPR2 BPR1 BPR0
Write:
Reset:00000000
U = Unaffected by reset. Initial value from factory is 1.
Write to this register by a programming sequence to the FLASH memory.
Figure 4-3. FLASH Block Protect Register (FLBPR)
1FLBPR VALUE
16-BIT MEMORY ADDRESS
0000000
START ADDRESS OF FLASH
BLOCK PROTECT