ATmega88 Boot Loader
Parameters
In Table 109 through Table 111, the parameters used in the description of the self pro-
gramming are given.
Table 109. Boot Size Configuration, ATmega88
Boot Reset
Boot
Loader
Flash
Address
(Start Boot
Loader
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 117.
Table 110. 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 256 and “RWW – Read-While-Write Section” on page 256
Table 111. Explanation of Different Variables used in Figure 118 and the Mapping to
the Z-pointer, ATmega88
Corresponding
Variable
Z-value(1)
Description
PCMSB
11
4
Most significant bit in the Program Counter.
(The Program Counter is 12 bits PC[11:0])
PAGEMSB
ZPCMSB
Most significant bit which is used to address the
words within one page (32 words in a page
requires 5 bits PC [4:0]).
Z12
Z5
Bit in Z-register that is mapped to PCMSB.
Because Z0 is not used, the ZPCMSB equals
PCMSB + 1.
ZPAGEMSB
Bit in Z-register that is mapped to PAGEMSB.
Because Z0 is not used, the ZPAGEMSB
equals PAGEMSB + 1.
PCPAGE
PC[11:5]
PC[4:0]
Z12:Z6
Z5:Z1
Program counter page address: Page select,
for page erase and page write
PCWORD
Program counter word address: Word select, for
filling temporary buffer (must be zero during
page write operation)
Note:
1. Z15:Z13: 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 261 for details about
the use of Z-pointer during Self-Programming.
268
ATmega48/88/168
2545D–AVR–07/04
ATMEL [ ATMEL ]
