ATMEGA169 ATMEL [ATMEL Corporation], ATMEGA169 Datasheet - Page 255

• Manufacturer Part Number: ATMEGA169
• Description: 8-bit Microcontroller with 16K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

Boot Loader Lock Bits
2514P–AVR–07/06
Figure 117. Memory Sections
Note:
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:
•
•
•
•
See Table 109 and Table 110 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 programming of the Flash memory by SPM instruction. Similarly, the gen-
eral Read/Write Lock (Lock Bit mode 1) does not control reading nor writing by
LPM/SPM, if it is attempted.
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.
1. The parameters in the figure above are given in Table 113 on page 264.
Boot Loader Flash Section
Boot Loader Flash Section
Application Flash Section
Application Flash Section
Application Flash Section
Application Flash Section
Program Memory
Program Memory
BOOTSZ = '11'
BOOTSZ = '01'
0x0000
End RWW
Start NRWW
End Application
Start Boot Loader
Flashend
0x0000
End RWW
Start NRWW
End Application
Start Boot Loader
Flashend
Boot Loader Flash Section
Boot Loader Flash Section
Application Flash Section
Application Flash Section
Application Flash Section
Program Memory
Program Memory
BOOTSZ = '10'
BOOTSZ = '00'
ATmega169/V
0x0000
End RWW
Start NRWW
End Application
Start Boot Loader
Flashend
0x0000
End RWW, End Application
Start NRWW, Start Boot Loader
Flashend
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