Table 24-14. Read-while-write Limit
Section
Pages
224
Address
Read-while-write section (RWW)
No read-while-write section (NRWW)
0x0000 - 0x6FFF
0x7000 - 0x7FFF
32
For details about these two section, see Section 24.3.2 “NRWW – No Read-while-write Section” on page 242 and Section
24.3.1 “RWW – Read-while-write Section” on page 242.
Table 24-15. Explanation of Different Variables used in Figure 24-3 and the Mapping to the Z-pointer
Corresponding
Variable
Z-value(1)
Description
Most significant bit in the program counter (the program counter
is 15 bits PC[14:0]).
PCMSB
14
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]).
PAGEMSB
ZPCMSB
Bit in Z-register that is mapped to PCMSB. Because Z0 is not
used, the ZPCMSB equals PCMSB + 1.
Z15
Z8
Bit in Z-register that is mapped to PAGEMSB. Because Z0 is not
used, the ZPAGEMSB equals PAGEMSB + 1.
ZPAGEMSB
PCPAGE
Program counter page address: Page select, for page erase and
page write
PC[14:7]
PC[6:0]
Z15:Z8
Z7:Z1
Program counter word address: Word select, for filling temporary
buffer (must be zero during page write operation)
PCWORD
Note:
1. Z15:Z13: always ignored
Z0: should be zero for all SPM commands, byte select for the LPM instruction.
See Section 24.6 “Addressing the Flash during Self-Programming” on page 246 for details about the use of
Z-pointer during self-programming.
254
ATmega16/32/64/M1/C1 [DATASHEET]
7647O–AVR–01/15
MICROCHIP [ MICROCHIP ]
