Note:
The different BOOTSZ Fuse configurations are shown in Figure 102.
Table 83. Read-While-Write Limit
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 207 and “RWW – Read-While-Write Section” on page 207
Table 84. Explanation of Different Variables used in Figure 103 and the Mapping to the
Z-pointer
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
PCWORD
PC[11:5]
PC[4:0]
Z12:Z6
Z5:Z1
Program counter page address: Page select,
for page erase and page write
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 211 for details about
the use of Z-pointer during Self-Programming.
218
ATmega8(L)
2486M–AVR–12/03
ATMEL [ ATMEL ]
