Datasheet
ATmega48/88/168 Automotive [DATASHEET]
7530K–AVR–07/14
240
24.7.13 ATmega88 Boot Loader Parameters
In Table 24-6 through Table 24-8, the parameters used in the description of the self programming are given.
For details about these two section, see Section 24.3.2 “NRWW – No Read-While-Write Section” on page 230 and
Section 24.3.1 “RWW – Read-While-Write Section” on page 230.
Table 24-6. Boot Size Configuration, ATmega88
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
Note: The different BOOTSZ fuse configurations are shown in Figure 24-2 on page 231.
Table 24-7. Read-While-Write Limit, ATmega88
Section Pages Address
Read-while-write section (RWW) 96 0x000 - 0xBFF
No read-while-write section (NRWW) 32 0xC00 - 0xFFF
Table 24-8. Explanation of Different Variables used in Figure 24-3 and the Mapping to the Z-pointer, ATmega88
Variable Corresponding Z-value
(1)
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 PAGEMSB + 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)
Note: 1. Z15:Z13: always ignored
Z0: should be zero for all SPM commands, byte select for the LPM instruction.
See Section 24.6 “Addressing the Flash During Self-Programming” on page 234 for details about the use of
Z-pointer during self-programming.