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Boot loader lock bits, Ee figure 94), Gure 94 – Rainbow Electronics ATmega162V User Manual

Page 218: Atmega162/v

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218

ATmega162/V

2513E–AVR–09/03

Figure 94. Memory Sections

(1)

Note:

1. The parameters are given in Table 94 on page 228.

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 indepen-
dently. 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 90 and Table 91 for further details. The Boot 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 program-

0x0000

Flashend

Program Memory

BOOTSZ = '11'

Application Flash Section

Boot Loader Flash Section

Flashend

Program Memory

BOOTSZ = '10'

0x0000

Program Memory

BOOTSZ = '01'

Program Memory

BOOTSZ = '00'

Application Flash Section

Boot Loader Flash Section

0x0000

Flashend

Application Flash Section

Flashend

End RWW

Start NRWW

Application flash Section

Boot Loader Flash Section

Boot Loader Flash Section

End RWW

Start NRWW

End RWW

Start NRWW

0x0000

End RWW, End Application

Start NRWW, Start Boot Loader

Application Flash Section

Application Flash Section

Application Flash Section

Read-While-Wr

ite Section

No Read-While-Wr

ite Section

Read-While-Wr

ite Section

No Read-While-Wr

ite Section

Read While Wr

ite

Section

No

Read While Wr

ite

Section

Read-While-Wr

ite Section

No Read-While-Wr

ite Section

End Application

Start Boot Loader

End Application

Start Boot Loader

End Application

Start Boot Loader