
268
8023F–AVR–07/09
ATmega325P/3250P
24.8.13
ATmega325P/3250P Boot Loader Parameters
In
Table 24-6 through
Table 24-8, the parameters used in the description of the Self-Programming are given.
Note:
1. The different BOOTSZ Fuse configurations are shown in
Figure 24-2Note:
Note:
Table 24-6.
Boot Size Configuration
BOOTSZ1
BOOTSZ0
Boot Size
Pages
Application
Flash Section
Boot Loader
Flash Section
End
Application
Section
Boot Reset
Address
(Start
Boot Loader
Section)
1
256 words
4
0x0000-0x3EFF
0x3F00-0x3FFF
0x3EFF
0x3F00
1
0
512 words
8
0x0000-0x3DFF
0x3E00-0x3FFF
0x3DFF
0x3E00
0
1
1024/ words
16
0x0000-0x3BFF
0x3C00-0x3FFF
0x3BFF
0x3C00
0
2048 words
32
0x0000-0x37FF
0x3800-0x3FFF
0x37FF
0x3800
Table 24-7.
Section
Pages
Address
Read-While-Write section (RWW)
224
0x0000 - 0x37FF
No Read-While-Write section (NRWW)
32
0x3800 - 0x3FFF
Table 24-8.
Explanation of different variables used in
Figure 24-3 and the mapping to the Z-pointer
Variable
Corresponding
Z-value
Description
PCMSB
13
Most significant bit in the Program Counter. (Program Counter is 14 bits
PC[13:0])
PAGEMSB
5
Most significant bit which is used to address the words within one page
(64 words in a page requires six/seven bits PC [5:0]).
ZPCMSB
Z14
Bit in Z-register that is mapped to PCMSB. Because Z0 is not used, the
ZPCMSB equals PCMSB + 1.
ZPAGEMSB
Z6
Bit in Z-register that is mapped to PCMSB. Because Z0 is not used, the
ZPAGEMSB equals PAGEMSB + 1.
PCPAGE
PC[13:6]
Z14:Z7
Program Counter page address: Page select, for Page Erase and Page
Write
PCWORD
PC[5:0]
Z6:Z1
Program Counter word address: Word select, for filling temporary buffer
(must be zero during Page Write operation)