at90pwm81-16se ATMEL Corporation, at90pwm81-16se Datasheet - Page 236

• Manufacturer Part Number: at90pwm81-16se
• Description: 8-bit Avr Microcontroller With 8k Bytes In- System Programmable Flash
• Manufacturer: ATMEL Corporation

21.4
236
Boot Loader Lock Bits
AT90PWM81
Figure 21-2.
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 independently. This gives the user a unique flex-
ibility to select different levels of protection.
The user can select:
See
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. Sim-
• 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.
Table 21-2
1. The parameters in the figure above are given in
Boot Loader Flash Section
Boot Loader Flash Section
Application Flash Section
Application Flash Section
Application Flash Section
Application Flash Section
and
Memory Sections
Program Memory
Program Memory
BOOTSZ = '11'
BOOTSZ = '01'
Table 21-3
for further details. The Boot Lock bits can be set in software and in Serial
0x0000
End RWW
Start NRWW
End Application
Start Boot Loader
Flashend
0x0000
End RWW
Start NRWW
End Application
Start Boot Loader
Flashend
Table 21-7 on page
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'
246.
0x0000
End RWW
Start NRWW
End Application
Start Boot Loader
Flashend
0x0000
End RWW, End Application
Start NRWW, Start Boot Loader
Flashend
7734M–AVR–03/10