
293
7674F–AVR–09/09
ATmega164P/324P/644P
24.8.16
ATmega644P Boot Loader Parameters
Note:
Note:
Note:
1. Z0: should be zero for all SPM commands, byte select for the LPM instruction.
Self-Programming.
Table 24-13. Boot Size Configurat
ion BOOTSZ1
BOOTSZ0
Boot Size
Pages
Application
Flash Section
Boot Loader
Flash Section
End Application
Section
Boot Reset
Address
(Start Boot
Loader Section)
1
512 words
4
0x0000 - 0xFDFF
0xFE00 - 0x7FFF
0xFDFF
0xFE00
1
0
1024 words
8
0x0000 - 0xFBFF
0xFC00 - 0x7FFF
0xFBFF
0xFC00
0
1
2048 words
16
0x0000 - 0xF7FF
0xF800 - 0x7FFF
0xF7FF
0xF800
0
4096 words
32
0x0000 - 0xEFFF
0xF000 - 0x7FFF
0xEFFF
0xF000
Table 24-14. Read-While-Write Limit
Section
Pages
Address
Read-While-Write section (RWW)
224
0x0000 - 0xEFFF
No Read-While-Write section (NRWW)
32
0xF000 - 0xFFFF
Table 24-15.
Variable
Correspondi
ng
Z-value
PCMSB
14
Most significant bit in the Program Counter. (The Program Counter is 15 bits
PC[14:0])
PAGEMSB
7
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-pointer that is mapped to PCMSB. Because Z0 is not used, the ZPCMSB
equals PCMSB + 1.
ZPAGEMSB
Z8
Bit in Z-pointer that is mapped to PCMSB. Because Z0 is not used, the
ZPAGEMSB equals PAGEMSB + 1.
PCPAGE
PC[14:7]
Z15:Z7
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)