Datasheet
ATmega48PA/88PA/168PA [DATASHEET]
9223F–AVR–04/14
248
27.8.15 Atmel ATmega168PA Boot Loader Parameters
In Table 27-10 through Table 27-12, the parameters used in the description of the self programming are given.
Note: The different BOOTSZ fuse configurations are shown in Figure 27-2 on page 239.
For details about these two section, see Section 27.4.2 “NRWW – No Read-while-write Section” on page 238 and Section
27.4.1 “RWW – Read-While-Write Section” on page 238
Table 27-10. Boot Size Configuration, Atmel ATmega168PA
BOOTSZ1 BOOTSZ0
Boot
Size Pages
Application
Flash Section
Boot Loader
Flash Section
End
Application
Section
Boot Reset Address
(Start Boot Loader
Section)
1 1 128 words 2 0x0000 - 0x1F7F 0x1F80 - 0x1FFF 0x1F7F 0x1F80
1 0 256 words 4 0x0000 - 0x1EFF 0x1F00 - 0x1FFF 0x1EFF 0x1F00
0 1 512 words 8
0x0000 -
0x1DFF
0x1E00 - 0x1FFF 0x1DFF 0x1E00
0 0 1024 words 16 0x0000 - 0x1BFF 0x1C00 - 0x1FFF 0x1BFF 0x1C00
Table 27-11. Read-While-Write Limit, Atmel ATmega168PA
Section Pages Address
Read-while-write section (RWW) 112 0x0000 - 0x1BFF
No read-while-write section (NRWW) 16 0x1C00 - 0x1FFF
Table 27-12. Explanation of Different Variables used in Figure 27-3 and the Mapping to the Z-pointer, Atmel
ATmega168PA
Variable
Corresponding
Z-value
(1)
Description
PCMSB 12
Most significant bit in the program counter (the program counter
is 13 bits PC[12:0])
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 Z13
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[12:6] Z13:Z7
Program counter page address: Page select, for page erase and
page write
PCWORD PC[5:0] Z6:Z1
Program 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. See Section 27.7 “Addressing
the Flash during Self-programming” on page 241 for details about the use of Z-pointer during Self-
Programming.