ATMEGA2561V ATMEL [ATMEL Corporation], ATMEGA2561V Datasheet - Page 339

• Manufacturer Part Number: ATMEGA2561V
• Description: 8-bit Microcontroller with 64K/128K/256K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

2549K–AVR–01/07
Table 148. Explanation of different variables used in Figure 137 and the mapping to the
Z-pointer, ATmega2560/2561
Notes:
Variable
PCMSB
PAGEMSB
ZPCMSB
ZPAGEMSB
PCPAGE
PCWORD
1. Z0: should be zero for all SPM commands, byte select for the (E)LPM instruction.
2. See “Addressing the Flash During Self-Programming” on page 328 for details about
3. The Z-register is only 16 bits wide. Bit 16 is located in the RAMPZ register in the I/O
the use of Z-pointer during Self-Programming.
map.
PC[16:7]
PC[6:0]
16
6
ATmega640/1280/1281/2560/2561
Corresponding
Z17:Z16
Z-value
Z17
Z7:Z1
Z7
(3)
:Z8
(2)
(3)
Description
Most significant bit in the Program Counter.
(The Program Counter is 17 bits PC[16:0])
Most significant bit which is used to address the
words within one page (128 words in a page
requires seven bits PC [6:0]).
Bit in Z-pointer that is mapped to PCMSB.
Because Z0 is not used, the ZPCMSB equals
PCMSB + 1.
Bit in Z-pointer that is mapped to PCMSB.
Because Z0 is not used, the ZPAGEMSB
equals PAGEMSB + 1.
Program Counter page address: Page select,
for Page Erase and Page Write
Program Counter word address: Word select,
for filling temporary buffer (must be zero during
Page Write operation)
(1)
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