Rainbow Electronics ATmega32L - Manual (Page 253)

253
ATmega32(L)
2503C–AVR–10/02
ATmega32 Boot Loader
Parameters In Table 100 through Table 102, the parameters used in the description of the self pro-
gramming are given.
Note: 1. The different BOOTSZ Fuse configurations are shown in Figure 125
Note: 1. For details about these two section, see “NRWW – No Read-While-Write Section” on
page 243 and “RWW – Read-While-Write Section” on page 243
Note: 1. Z15: 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 247 for details about
the use of Z-pointer during Self-Programming.
Table 100. Boot Size Configuration (1)
BOOTSZ1 BOOTSZ0
Boot
Size
Pages
Application
Flash
Section
Boot
Loader
Flash
Section
End
Application
section
Boot Reset
Address
(start Boot
Loader
Section)
1 1
256
words
4
$0000 -
$3EFF $3F00 -
$3FFF
$3EFF $3F00
1 0
512
words
8
$0000 -
$3DFF $3E00 -
$3FFF
$3DFF $3E00
0 1
1024
words
16
$0000 -
$3BFF $3C00 -
$3FFF
$3BFF $3C00
0 0
2048
words
32
$0000 -
$37FF $3800 -
$3FFF
$37FF $3800
Table 101. Read-While-Write Limit (1)
Section Pages Address
Read-While-Write section (RWW) 224 $0000 - $37FF
No Read-While-Write section (NRWW) 32 $3800 - $3FFF
Table 102. Explanation of Different Variables used in Figure 126 and the Mapping to
the Z-pointer
Variable
Corresponding
Z-value (1) Description
PCMSB
13 Most significant bit in the program counter. (The
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 6 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 PAGEMSB.
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)