Datasheet
247
7734Q–AVR–02/12
AT90PWM81/161
For AT90PWM161.
The different BOOTSZ Fuse configurations are shown in Figure 20-2 on page 236.
For details about these two section, see “NRWW – No Read-While-Write Section” on page 234
and “RWW – Read-While-Write Section” on page 234.
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 239 for details about the use of
Z-pointer during Self-Programming.
Table 20-8. 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 1 256 words 4
0x000 -
0x1EFF
0x1F00 -
0x1FFF
0x1EFF 0x1F00
1 0 512 words 8
0x000 -
0x1DFF
0x1E00 -
0x1FFF
0x1DFF 0x1E00
01
1024
words
16
0x000 -
0x1BFF
0x1C00 -
0x1FFF
0x1BFF 0x1C00
00
2048
words
32
0x000 -
0x17FF
0x1800 -
0x1FFF
0x17FF 0x1800
Table 20-9. Read-while-write limit.
Section Pages Address
Read-while-write section (RWW) 96 0x000 - 0x17FF
No read-while-write section (NRWW) 32 0x1800 - 0x1FFF
Table 20-10. Explanation of different variables used in Figure 20-3 on page 240 and the mapping to the Z-pointer.
Variable AT90PWM81
AT90PWM81
correspond-
ing Z-value
(1)
AT90PWM161
AT90PWM161
correspond-
ing Z-value
(1)
Description
PCMSB 11 12
Most significant bit in the Program Counter.
(The Program Counter is 12 bits PC[11:0])
PAG EMSB 4 4
Most significant bit which is used to address the
words within one page
(32 words in a page requires 5 bits PC [4:0])
ZPCMSB Z12 Z12
Bit in Z-register that is mapped to PCMSB.
Because Z0 is not used, the ZPCMSB equals
PCMSB + 1
ZPAGEMS
B
Z5 Z5
Bit in Z-register that is mapped to PAGEMSB.
Because Z0 is not used, the ZPAGEMSB equals
PAGEMSB + 1
PCPAGE PC[11:5] Z12:Z6 PC[12:6] Z12:Z6
Program counter page address:
Page select, for page erase and page write
PCWORD PC[4:0] Z5:Z1 PC[5:0] Z5:Z1
Program counter word address:
Word select, for filling temporary buffer (must be
zero during page write operation)