mc68hc908qf4 Freescale Semiconductor, Inc, mc68hc908qf4 Datasheet - Page 35

• Manufacturer Part Number: mc68hc908qf4
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

2.6.6 FLASH Block Protect Register
MC68HC908QF4 — Rev. 1.0
MOTOROLA
When bits within the FLBPR are programmed, they lock a block of memory. The
address ranges are shown in
FLBPR is programmed with a value other than $FF, any erase or program of the
FLBPR or the protected block of FLASH memory is prohibited. Mass erase is
disabled whenever any block is protected (FLBPR does not equal $FF). The
FLBPR itself can be erased or programmed only with an external voltage, V
present on the IRQ pin. This voltage also allows entry from reset into the monitor
mode.
The FLASH block protect register 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 address of the
protected range within the FLASH memory.
BPR[7:0] — FLASH Protection Register Bits [7:0]
U = Unaffected by reset. Initial value from factory is 1.
Write to this register is by a programming sequence to the FLASH memory.
These eight bits in FLBPR represent bits [13:6] of a 16-bit memory address. Bits
[15:14] are 1s and bits [5:0] are 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, XX40, XX80, or XXC0 within the FLASH
memory. See
Address:
FLASH BLOCK PROTECT
Reset:
Read:
Write:
START ADDRESS OF
Freescale Semiconductor, Inc.
For More Information On This Product,
$FFBE
BPR7
Bit 7
U
Figure 2-5. FLASH Block Protect Register (FLBPR)
Figure 2-6. FLASH Block Protect Start Address
Figure 2-6
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BPR6
U
6
1
Memory
1
and
2.6.6 FLASH Block Protect
BPR5
U
5
Table
16-BIT MEMORY ADDRESS
FLBPR VALUE
2-2.
BPR4
U
4
BPR3
U
3
BPR2
0
FLASH Memory (FLASH)
Register. Once the
U
2
0
0
BPR1
U
1
0
0
Data Sheet
Memory
BPR0
TST
Bit 0
0
U
,
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