ATmega48PA/88PA/168PA/328P
26.8.15 ATmega168PA Boot Loader Parameters
In Table 26-10 through Table 26-12, the parameters used in the description of the self programming are given.
Table 26-10. Boot Size Configuration, ATmega168PA
Boot
Application
Flash
Section
Loader
Flash
Section
End
Application
Section
Boot
Size
Boot Reset Address (Start Boot
Loader Section)
BOOTSZ1
BOOTSZ0
Pages
1
1
0
0
1
0
1
0
128 words
256 words
2
4
0x0000 - 0x1F7F
0x0000 - 0x1EFF
0x0000 - 0x1DFF
0x0000 - 0x1BFF
0x1F80 - 0x1FFF
0x1F00 - 0x1FFF
0x1E00 - 0x1FFF
0x1C00 - 0x1FFF
0x1F7F
0x1EFF
0x1DFF
0x1BFF
0x1F80
0x1F00
0x1E00
0x1C00
512 words
1024 words
Note:
8
16
The different BOOTSZ Fuse configurations are shown in Figure 26-2 on page 280.
Table 26-11. Read-While-Write Limit, ATmega168PA
Section
Pages
112
Address
Read-While-Write section (RWW)
No Read-While-Write section (NRWW)
0x0000 - 0x1BFF
0x1C00 - 0x1FFF
16
For details about these two section, see ”NRWW – No Read-While-Write Section” on page 278 and ”RWW – Read-While-
Write Section” on page 278
Table 26-12. Explanation of Different Variables used in Figure 26-3 and the Mapping to the Z-pointer, ATmega168PA
Corresponding
Variable
Z-value(1)
Description
Most significant bit in the Program Counter. (The Program Counter
is 13 bits PC[12:0])
PCMSB
12
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])
PAGEMSB
ZPCMSB
ZPAGEMSB
PCPAGE
Bit in Z-register that is mapped to PCMSB. Because Z0 is not used,
the ZPCMSB equals PCMSB + 1.
Z13
Z6
Bit in Z-register that is mapped to PAGEMSB. Because Z0 is not
used, the ZPAGEMSB equals PAGEMSB + 1.
Program counter page address: Page select, for page erase and
page write
PC[12:6]
PC[5:0]
Z13:Z7
Z6:Z1
Program counter word address: Word select, for filling temporary
buffer (must be zero during page write operation)
PCWORD
Note:
1. Z15:Z14: always ignored
Z0: should be zero for all SPM commands, byte select for the LPM instruction.
See ”Addressing the Flash During Self-Programming” on page 282 for details about the use of Z-pointer during Self-
Programming.
290
8161D–AVR–10/09
ATMEL [ ATMEL ]
