MC68HC908AS32A Datasheet, PDF (53/280 Pages) Freescale Semiconductor, Inc – Microcontrollers

Table 2-6. FLASH Protected Ranges
FLBPR[7:0]
$FF
$FE
$FD
Protected Range
No Protection
$FF00 – $FFFF
$FE80 – $FFFF
FLASH Memory (FLASH)
$0B
$8580 – $FFFF
$0A
$8500 – $FFFF
$09
$8480 – $FFFF
$08
$8400 – $FFFF
$04
$8200 – $FFFF
$03
$8180 – $FFFF
$02
$8100 – $FFFF
$01
$8080 – $FFFF
$00
$8000 – $FFFF
2.9.2 FLASH Block Protection
Due to the ability of the on-board charge pump to erase and program the FLASH memory in the target
application, provision is made for protecting blocks of memory from unintentional erase or program
operations due to system malfunction. This protection is done by using the FLASH block protection
register (FLBPR). FLBPR determines the range of the FLASH memory which is to be protected. The
range of the protected area starts from a location defined by FLBPR and ends at the bottom of the FLASH
memory ($FFFF). When the memory is protected, the HVEN bit can not be set in either ERASE or
PROGRAM operations.
NOTE
In performing a program or erase operation, FLBPR must be read after
setting the PGM or ERASE bit and before asserting the HVEN bit.
When the FLBPR is programmed with all 0s, the entire memory is protected from being programmed and
erased. When all the bits are erased (all 1s), the entire memory is accessible for program and erase.
When bits within FLBPR are programmed (0s), they lock a block of memory address ranges as shown in
2.9.1.2 FLASH Block Protect Register. If FLBPR is programmed with any value other than $FF, the
protected block of FLASH memory can not be erased or programmed.
NOTE
The vector locations and the FLBPR are located in the same page. FLBPR
is not protected with special hardware or software; therefore, if this page is
not protected by FLBPR and the vector locations are erased by either a
page or a mass erase operation, FLBPR will also be erased.
MC68HC908AS32A Data Sheet, Rev. 2.0
Freescale Semiconductor
53