ATmega88PA Automotive Atmel Corporation, ATmega88PA Automotive Datasheet - Page 281

• Manufacturer Part Number: ATmega88PA Automotive
• Manufacturer: Atmel Corporation

27.5
9223B–AVR–09/11
Boot Loader Lock Bits
If no Boot Loader capability is needed, the entire Flash is available for application code. The
Boot Loader has two separate sets of Boot Lock bits which can be set independently. This
gives the user a unique flexibility to select different levels of protection.
The user can select:
See
and in Serial or Parallel Programming mode, but they can be cleared by a Chip Erase com-
mand only. The general Write Lock (Lock Bit mode 2) does not control the programming of the
Flash memory by SPM instruction. Similarly, the general Read/Write Lock (Lock Bit mode 1)
does not control reading nor writing by LPM/SPM, if it is attempted.
Table 27-2.
Table 27-3.
Note:
Note:
• To protect the entire Flash from a software update by the MCU.
• To protect only the Boot Loader Flash section from a software update by the MCU.
• To protect only the Application Flash section from a software update by the MCU.
• Allow software update in the entire Flash.
BLB0 Mode
BLB1 Mode
Atmel ATmega48PA/88PA/168PA [Preliminary]
Table 27-2
1
2
3
4
1
2
3
4
1. “1” means unprogrammed, “0” means programmed
1. “1” means unprogrammed, “0” means programmed
Boot Lock Bit0 Protection Modes (Application Section)
Boot Lock Bit1 Protection Modes (Boot Loader Section)
and
BLB02
BLB12
1
1
0
0
1
1
0
0
Table 27-3
BLB01
BLB11
1
0
0
1
1
0
0
1
for further details. The Boot Lock bits can be set in software
Protection
No restrictions for SPM or LPM accessing the Application
section.
SPM is not allowed to write to the Application section.
SPM is not allowed to write to the Application section, and LPM
executing from the Boot Loader section is not allowed to read
from the Application section. If Interrupt Vectors are placed in the
Boot Loader section, interrupts are disabled while executing from
the Application section.
LPM executing from the Boot Loader section is not allowed to
read from the Application section. If Interrupt Vectors are placed
in the Boot Loader section, interrupts are disabled while
executing from the Application section.
Protection
No restrictions for SPM or LPM accessing the Boot Loader
section.
SPM is not allowed to write to the Boot Loader section.
SPM is not allowed to write to the Boot Loader section, and LPM
executing from the Application section is not allowed to read from
the Boot Loader section. If Interrupt Vectors are placed in the
Application section, interrupts are disabled while executing from
the Boot Loader section.
LPM executing from the Application section is not allowed to read
from the Boot Loader section. If Interrupt Vectors are placed in
the Application section, interrupts are disabled while executing
from the Boot Loader section.
(1)
(1)
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