MC68HC908GZ60 Datasheet, PDF (47/352 Pages) Freescale Semiconductor, Inc – Microcontrollers

FLASH-1 Memory (FLASH-1)
2.6.2.2 FLASH-1 Block Protect Register
The FLASH-1 block protect register (FL1BPR) is implemented as a byte within the FLASH-1 memory;
therefore, it can only be written during a FLASH programming sequence. The value in this register
determines the starting location of the protected range within the FLASH-1 memory.
Address: $FF80
Bit 7
6
5
4
3
2
1
Read:
BPR7
Write:
BPR6
BPR5
BPR4
BPR3
Unaffected by reset
BPR2
BPR1
Figure 2-4. FLASH-1 Block Protect Register (FL1BPR)
Bit 0
BPR0
FL1BPR[7:0] — Block Protect Register Bits 7 to 0
These eight bits represent bits [14:7] of a 16-bit memory address. Bit 15 is a 1 and bits [6:0] are 0s.
The resultant 16-bit address is used for specifying the start address of the FLASH-1 memory for block
protection. FLASH-1 is protected from this start address to the end of FLASH-1 memory at $FFFF.
With this mechanism, the protect start address can be $XX00 and $XX80 (128 byte page boundaries)
within the FLASH-1 array.
START ADDRESS OF FLASH
BLOCK PROTECT
1
16-BIT MEMORY ADDRESS
FLBPR VALUE
0000000
Figure 2-5. FLASH-1 Block Protect Start Address
Table 2-2. FLASH-1 Protected Ranges
FL1BPR[7:0]
$FF
$FE
$FD
↓
$0B
$0A
$09
$08
↓
$04
$03
$02
$01
$00
Protected Range
No protection
$FF00–$FFFF
$FE80–$FFFF
↓
$8580–$FFFF
$8500–$FFFF
$8480–$FFFF
$8400–$FFFF
↓
$8200–$FFFF
$8180–$FFFF
$8100–$FFFF
$8080–$FFFF
$8000–$FFFF
Decreasing the value in FL1BPR by one increases the protected range by one page (128 bytes).
However, programming the block protect register with $FE protects a range twice that size, 256 bytes, in
the corresponding array. $FE means that locations $FF00–$FFFF are protected in FLASH-1.
The FLASH memory does not exist at some locations. The block protection range configuration is
unaffected if FLASH memory does not exist in that range. Refer to Figure 2-1 and make sure that the
desired locations are protected.
MC68HC908GZ60 • MC68HC908GZ48 • MC68HC908GZ32 Data Sheet, Rev. 6
Freescale Semiconductor
47