Datasheet

Table 31-6. Boot Size Configuration
BOOTSZ1 BOOTSZ0 Boot
Size
Pages Application
Flash Section
Boot
Loader
Flash
Section
End
Application
Section
Boot Reset
Address
(Start Boot
Loader
Section)
1 1 256
words
4 0x0000 -
0x3EFF
0x3F00 -
0x3FFF
0x3EFF 0x3F00
1 0 512
words
8 0x0000 -
0x3DFF
0x3E00 -
0x3FFF
0x3DFF 0x3E00
0 1 1024
words
16 0x0000 -
0x3BFF
0x3C00 -
0x3FFF
0x3BFF 0x3C00
0 0 2048
words
32 0x0000 -
0x37FF
0x3800 -
0x3FFF
0x37FF 0x3800
Note: The different BOOTSZ Fuse configurations are shown in Figure 31-2.
Table 31-7. Read-While-Write Limit
Section Pages Address
Read-While-Write section (RWW) 224 0x0000 - 0x37FF
No Read-While-Write section (NRWW) 32 0x3800 - 0x3FFF
Note: For details about these two sections, see NRWW – No Read-While-Write Section and RWW –
Read-While-Write Section.
Table 31-8. Explanation of Different Variables used in Figure and the Mapping to the Z-pointer
Variable Corresponding
Variable
(1)
Description
PCMSB 13 Most significant bit in the Program Counter. (The Program
Counter is 14 bits PC[13:0].)
PAGEMSB 5 Most significant bit which is used to address the words
within one page (64 words in a page requires 6 bits PC
[5:0]).
ZPCMSB Z14 Bit in Z-register that is mapped to PCMSB. Because Z0 is
not used, the ZPCMSB equals PCMSB + 1.
ZPAGEMSB Z6 Bit in Z-register that is mapped to PAGEMSB. Because
Z0 is not used, the ZPAGEMSB equals PAGEMSB + 1.
PCPAGE PC[13:6] Z[14:7] Program counter page address: Page select, for page
erase and page write.
PCWORD PC[5:0] Z[6:1] Program counter word address: Word select, for filling
temporary buffer (must be zero during page write
operation).
ATmega328PB
BTLDR - Boot Loader Support – Read-While-Wri...
© 2018 Microchip Technology Inc.
Datasheet Complete
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