26.8.13 ATmega88 Boot Loader Parameters
In Table 26-6 through Table 26-8, the parameters used in the description of the self program-
ming are given.
Table 26-6. Boot Size Configuration, ATmega88
Boot Reset
Address
(Start Boot
Loader
Boot
Loader
Flash
Application
Flash
Section
End
Application
Section
Boot
Size
BOOTSZ1
BOOTSZ0
Pages
Section
Section)
128
words
0x000 -
0xF7F
0xF80 -
0xFFF
1
1
4
0xF7F
0xEFF
0xDFF
0xBFF
0xF80
0xF00
0xE00
0xC00
256
words
0x000 -
0xEFF
0xF00 -
0xFFF
1
0
0
0
1
0
8
512
words
0x000 -
0xDFF
0xE00 -
0xFFF
16
32
1024
words
0x000 -
0xBFF
0xC00 -
0xFFF
Note:
The different BOOTSZ Fuse configurations are shown in Figure 26-2.
Table 26-7. Read-While-Write Limit, ATmega88
Section
Pages
96
Address
Read-While-Write section (RWW)
No Read-While-Write section (NRWW)
0x000 - 0xBFF
0xC00 - 0xFFF
32
For details about these two section, see “NRWW – No Read-While-Write Section” on page 271
and “RWW – Read-While-Write Section” on page 271
Table 26-8. Explanation of Different Variables used in Figure 26-3 and the Mapping to the Z-
pointer, ATmega88
Corresponding
Variable
Z-value(1)
Description
Most significant bit in the Program Counter. (The
Program Counter is 12 bits PC[11:0])
PCMSB
11
4
Most significant bit which is used to address the
words within one page (32 words in a page requires
5 bits PC [4:0]).
PAGEMSB
ZPCMSB
Bit in Z-register that is mapped to PCMSB. Because
Z0 is not used, the ZPCMSB equals PCMSB + 1.
Z12
Z5
Bit in Z-register that is mapped to PAGEMSB.
Because Z0 is not used, the ZPAGEMSB equals
PAGEMSB + 1.
ZPAGEMSB
PCPAGE
Program counter page address: Page select, for
page erase and page write
PC[11:5]
PC[4:0]
Z12:Z6
Z5:Z1
Program counter word address: Word select, for
filling temporary buffer (must be zero during page
write operation)
PCWORD
Note:
1. Z15:Z13: always ignored
Z0: should be zero for all SPM commands, byte select for the LPM instruction.
282
ATmega48/88/168
2545M–AVR–09/07
ATMEL [ ATMEL ]
