Rainbow-electronics ATmega128L Uživatelský manuál stáhnout pdf (Strana 278)

278

ATmega128(L)

2467B–09/01

Notes: 1. The Z-register is only 15 bits wide. Bit 16 is located in the RAMPZ register in the I/O

map.

2. Z0: should be zero for all SPM commands, byte select for the (E)LPM instruction.

3. See “Addressing the Flash During Self-Programming” on page 271 for details about

the use of Z-pointer during self-programming.

Table 115. Explanation of Different Variables Used in Figure 134 and the Mapping to

the Z-Pointer

(3)

Variable

Corresponding

Z-value Description

(2)

PCMSB

15 Most significant bit in the program counter. (The

program counter is 16 bits PC[15:0])

PAG EM SB

6 Most significant bit which is used to address the

words within one page (128 words in a page

requires 7 bits PC [6:0]).

ZPCMSB

Z16

(1)

Bit in Z-register that is mapped to PCMSB.

Because Z0 is not used, the ZPCMSB equals

PCMSB + 1.

ZPAGEMSB

Z7 Bit in Z-register that is mapped to PCMSB.

Because Z0 is not used, the ZPAGEMSB

equals PAGEMSB + 1.

PCPAGE

PC[15:7] Z16

(1)

: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)

1 2 ... 273 274 275 276 277 278 279 280 281 282 283 ... 330 331

Žádné komentáře

Rainbow-electronics ATmega128L Uživatelský manuál Strana 278