289
8025I–AVR–02/09
ATmega48P/88P/168P/328P
24.8.14
ATmega88P Boot Loader Parameters
In
through
, the parameters used in the description of the self programming are given.
Note:
The different BOOTSZ Fuse configurations are shown in
.
For details about these two section, see
”NRWW – No Read-While-Write Section” on page 278
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 282
for details about the use of Z-pointer during Self-
Programming.
Table 24-7.
Boot Size Configuration, ATmega88P
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
4
0x000 - 0xF7F
0xF80 - 0xFFF
0xF7F
0xF80
1
0
256 words
8
0x000 - 0xEFF
0xF00 - 0xFFF
0xEFF
0xF00
0
1
512 words
16
0x000 - 0xDFF
0xE00 - 0xFFF
0xDFF
0xE00
0
0
1024 words
32
0x000 - 0xBFF
0xC00 - 0xFFF
0xBFF
0xC00
Table 24-8.
Read-While-Write Limit, ATmega88P
Section
Pages
Address
Read-While-Write section (RWW)
96
0x000 - 0xBFF
No Read-While-Write section (NRWW)
32
0xC00 - 0xFFF
Table 24-9.
Explanation of Different Variables used in
and the Mapping to the Z-pointer, ATmega88P
Variable
Corresponding
Z-value
Description
PCMSB
11
Most significant bit in the Program Counter. (The Program Counter is
12 bits PC[11:0])
PAGEMSB
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]).
ZPCMSB
Z12
Bit in Z-register that is mapped to PCMSB. Because Z0 is not used,
the ZPCMSB equals PCMSB + 1.
ZPAGEMSB
Z5
Bit in Z-register that is mapped to PAGEMSB. Because Z0 is not
used, the ZPAGEMSB equals P 1.
PCPAGE
PC[11:5]
Z12:Z6
Program counter page address: Page select, for page erase and
page write
PCWORD
PC[4:0]
Z5:Z1
Program counter word address: Word select, for filling temporary
buffer (must be zero during page write operation)