32.8.15 ATmega168PB Boot Loader Parameters

The following tables are the parameters used in the description of the self programming are given.

Table 32-9. Boot Size Configuration, ATmega168PB
BOOTSZ1BOOTSZ0Boot SizePagesApplication Flash SectionBoot Loader Flash SectionEnd Application SectionBoot Reset Address
(Start Boot Loader Section)
11128 words20x0000 - 0x1F7F0x1F80 - 0x1FFF0x1F7F0x1F80
10256 words40x0000 - 0x1EFF0x1F00 - 0x1FFF0x1EFF0x1F00
01512 words80x0000 - 0x1DFF0x1E00 - 0x1FFF0x1DFF0x1E00
001024 words160x0000 - 0x1BFF0x1C00 - 0x1FFF0x1BFF0x1C00
Note: The different BOOTSZ Fuse configurations are shown in Figure 32-2.
Table 32-10. Read-While-Write Limit, ATmega168PB
SectionPagesAddress
Read-While-Write section (RWW)1120x0000 - 0x1BFF
No Read-While-Write section (NRWW)160x1C00 - 0x1FFF

For details about these two section, please refer to NRWW – No Read-While-Write Section and RWW – Read-While-Write Section.

Table 32-11. Explanation of Different Variables used in Figure 32-3, ATmega168PB
VariableCorresponding
Z-value(1)Description
PCMSB12Most significant bit in the Program Counter. (The Program Counter is 13 bits PC[12:0])
PAGEMSB5Most significant bit which is used to address the words within one page (64 words in a page requires 6 bits PC [5:0])
ZPCMSBZ13Bit in Z-register that is mapped to PCMSB. Because Z0 is not used, the ZPCMSB equals PCMSB + 1.
ZPAGEMSBZ6Bit in Z-register that is mapped to PAGEMSB. Because Z0 is not used, the ZPAGEMSB equals PAGEMSB + 1.
PCPAGEPC[12:6]Z13:Z7 Program counter page address: Page select, for page erase and page write
PCWORDPC[5:0]Z6:Z1Program counter word address: Word select, for filling temporary buffer (must be zero during page write operation)
Note: 1. Z15:Z14: always ignored



Z0: should be zero for all SPM commands, byte select for the LPM instruction.


Please refer to Addressing the Flash During Self-Programming or details about the use of Z-pointer during Self- Programming.