ATMEGA329V_14 Datasheet, PDF (281/392 Pages) ATMEL Corporation – High Performance, Low Power Atmel

Figure 26-2. Memory Sections
Program Memory
BOOTSZ = '11'
0x0000
Application Flash Section
ATmega329/3290/649/6490
Program Memory
BOOTSZ = '10'
0x0000
Application Flash Section
Application Flash Section
Boot Loader Flash Section
Program Memory
BOOTSZ = '01'
End RWW
Start NRWW
End Application
Start Boot Loader
Flashend
0x0000
Application Flash Section
Application Flash Section
Boot Loader Flash Section
Program Memory
BOOTSZ = '00'
End RWW
Start NRWW
End Application
Start Boot Loader
Flashend
0x0000
Application Flash Section
Application Flash Section
Boot Loader Flash Section
End RWW
Start NRWW
End Application
Start Boot Loader
Flashend
End RWW, End Application
Start NRWW, Start Boot Loader
Boot Loader Flash Section
Flashend
Note: 1. The parameters in the figure above are given in Table 26-6 on page 290.
26.4
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:
• 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.
See Table 26-2 and Table 26-3 for further details. The Boot Lock bits and general Lock bits can
be set in software and in Serial or Parallel Programming mode, but they can be cleared by a
Chip Erase command only. The general Write Lock (Lock Bit mode 2) does not control the pro-
gramming 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.
2552K–AVR–04/11
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