Datasheet

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27.8.14. ATmega644A Boot Loader Parameters
In the following tables, the parameters used in the description of the self programming are given.
Table 27-7. Boot Size Configuration, ATmega644A
BOOTSZ1 BOOTSZ0 Boot
Size
Pages Application
Flash Section
Boot
Loader
Flash
Section
End
Application
Section
Boot Reset
Address
(Start Boot
Loader
Section)
1 1 512
words
4 0x0000 -
0x7DFF
0x7E00 -
0x7FFF
0x7DFF 0x7E00
1 0 1024
words
8 0x0000 -
0x7BFF
0x7C00 -
0x7FFF
0x7BFF 0x7C00
0 1 2048
words
16 0x0000 -
0x77FF
0x7800 -
0x7FFF
0x77FF 0x7800
0 0 4096
words
32 0x0000 -
0x7FFF
0x7000 -
0x3FFF
0x6FFF 0x7000
Note: The different BOOTSZ Fuse configurations are shown in Figure 27-2
Table 27-8. Read-While-Write Limit, ATmega644A
Section Pages Address
Read-While-Write section (RWW) 224 0x0000 - 0x6FFF
No Read-While-Write section (NRWW) 32 0x7000 - 0x7FFF
Note: For details about these two section, see NRWW – No Read-While-Write Section and RWW –
Read-While-Write Section.
Table 27-9. Explanation of Different Variables used in Figure and the Mapping to the Z-pointer, ATmega644A
Variable Corresponding
Variable
(1)
Description
PCMSB 14 Most significant bit in the Program Counter. (The Program
Counter is 15 bits PC[14:0])
PAGEMSB 6 Most significant bit which is used to address the words
within one page (128 words in a page requires 7 bits PC
[6:0]).
ZPCMSB Z15 Bit in Z-register that is mapped to PCMSB. Because Z0 is
not used, the ZPCMSB equals PCMSB + 1.
ZPAGEMSB Z7 Bit in Z-register that is mapped to PAGEMSB. Because
Z0 is not used, the ZPAGEMSB equals PAGEMSB + 1.
Atmel ATmega644A [DATASHEET]
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