MC68HC908AZ32ACFU MOTOROLA [Motorola, Inc], MC68HC908AZ32ACFU Datasheet - Page 68

• Manufacturer Part Number: MC68HC908AZ32ACFU
• Description: Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

FLASH Memory
4.5 FLASH Block Protection
Advance Information
68
NOTE:
NOTE:
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.
In performing a program or erase operation, the FLASH Block Protect
Register must be read after setting the PGM or ERASE bit and before
asserting the HVEN bit.
When the FLASH Block Protect Register is programmed with all 0’s, the
entire memory is protected from being programmed and erased. When
all the bits are erased (all 1’s), the entire memory is accessible for
program and erase.
When bits within FLBPR are programmed (logic 0), they lock a block of
memory address ranges as shown in
on page 66. If FLBPR is programmed with any value other than $FF, the
protected block of FLASH memory can not be erased or programmed.
The vector locations and the FLASH Block Protect Registers 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 get erased.
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
FLASH Memory
FLASH Block Protect Register
68HC908AZ32A — Rev 0.0
MOTOROLA