Datasheet
289
2490R–AVR–02/2013
ATmega64(L)
ATmega64 Boot
Loader Parameters
In Table 112 through Table 114, the parameters used in the description of the Self-programming
are given.
Note: 1. The different BOOTSZ Fuse configurations are shown in Figure 136
Note: 1. For details about these two section, see “NRWW – No Read-While-Write Section” on page
278 and “RWW – Read-While-Write Section” on page 278
Notes: 1. Z0: should be zero for all SPM commands, byte select for the LPM instruction.
2. See “Addressing the Flash During Self-programming” on page 283 for details about the use of
Z-pointer during Self-programming.
Table 112. Boot Size Configuration
(1)
BOOTSZ
1
BOOTSZ
0
Boot
Size Pages
Appli-
cation
Flash
Section
Boot
Loader
Flash
Section
End
Applic-
ation
Section
Boot Reset
Address
(Start Boot
Loader
Section)
11
512
words
4
0x0000 -
0x7DFF
0x7E00 -
0x7FFF
0x7DFF 0x7E00
10
1024
words
8
0x0000 -
0x7BFF
0x7C00 -
0x7FFF
0x7BFF 0x7C00
01
2048
words
16
0x0000 -
0x77FF
0x7800 -
0x7FFF
0x77FF 0x7800
00
4096
words
32
0x0000 -
0x6FFF
0x7000 -
0x7FFF
0x6FFF 0x7000
Table 113. Read-While-Write Limit
(1)
Section Pages Address
Read-While-Write (RWW) 224 0x0000 - 0x6FFF
No Read-While-Write (NRWW) 32 0x7000 - 0x7FFF
Table 114. Explanation of Different Variables Used in Figure 137 and the Mapping to the Z-
pointer
(1)(2)
Variable
Corresponding
Z-value
Description
PCMSB
14 Most significant bit in the Program Counter.
(The Program Counter is 15 bits PC[14:0]).
PAG EMSB
6 Most significant bit which is used to address the
words within one page (128 words in a page
requires seven bits PC [6:0]).
ZPCMSB
Z15 Bit in Z-register that is mapped to PCMSB.
Because Z0 is not used, the ZPCMSB equals
PCMSB + 1.
ZPAGEMSB
Z7 Bit in Z-register that is mapped to PAGEMSB.
Because Z0 is not used, the ZPAGEMSB
equals PAGEMSB + 1.
PCPAGE
PC[14:7] Z15:Z8 Program Counter page address: Page select,
for Page Erase and Page Write
PCWORD
PC[6:0] Z7:Z1 Program Counter word address: Word select,
for filling temporary buffer (must be zero during
Page Write operation)