Atmel ATmega328P Xplained Mini MEGA328P-XMINI MEGA328P-XMINI 数据表
产品代码
MEGA328P-XMINI
257
ATmega48A/PA/88A/PA/168A/PA/328/P [DATASHEET]
Atmel-8271H-AVR- ATmega-Datasheet_08/2014
26.1.3 Performing a Page Write
To execute Page Write, set up the address in the Z-pointer, write “00000101” to SPMCSR and execute SPM
within four clock cycles after writing SPMCSR. The data in R1 and R0 is ignored. The page address must be
written to PCPAGE. Other bits in the Z-pointer must be written to zero during this operation.
within four clock cycles after writing SPMCSR. The data in R1 and R0 is ignored. The page address must be
written to PCPAGE. Other bits in the Z-pointer must be written to zero during this operation.
The CPU is halted during the Page Write operation.
26.2
Addressing the Flash During Self-Programming
The Z-pointer is used to address the SPM commands.
), the Program Counter can be treated as
having two different sections. One section, consisting of the least significant bits, is addressing the words within
a page, while the most significant bits are addressing the pages. This is shown in
a page, while the most significant bits are addressing the pages. This is shown in
that the Page Erase and Page Write operations are addressed independently. Therefore it is of major
importance that the software addresses the same page in both the Page Erase and Page Write operation.
importance that the software addresses the same page in both the Page Erase and Page Write operation.
The LPM instruction uses the Z-pointer to store the address. Since this instruction addresses the Flash byte-by-
byte, also the LSB (bit Z0) of the Z-pointer is used.
byte, also the LSB (bit Z0) of the Z-pointer is used.
Figure 26-1.
Addressing the Flash During SPM
Note:
1. The different variables used in
are listed in
.
26.2.1 EEPROM Write Prevents Writing to SPMCSR
Note that an EEPROM write operation will block all software programming to Flash. Reading the Fuses and
Lock bits from software will also be prevented during the EEPROM write operation. It is recommended that the
user checks the status bit (EEPE) in the EECR Register and verifies that the bit is cleared before writing to the
SPMCSR Register.
Lock bits from software will also be prevented during the EEPROM write operation. It is recommended that the
user checks the status bit (EEPE) in the EECR Register and verifies that the bit is cleared before writing to the
SPMCSR Register.
Bit
15
14
13
12
11
10
9
8
ZH (R31)
Z15
Z14
Z13
Z12
Z11
Z10
Z9
Z8
ZL (R30)
Z7
Z6
Z5
Z4
Z3
Z2
Z1
Z0
7
6
5
4
3
2
1
0
PROGRAM MEMORY
0
1
15
Z - REGISTER
BIT
0
ZPAGEMSB
WORD ADDRESS
WITHIN A PAGE
WITHIN A PAGE
PAGE ADDRESS
WITHIN THE FLASH
WITHIN THE FLASH
ZPCMSB
INSTRUCTION WORD
PAGE
PCWORD[PAGEMSB:0]:
00
01
02
PAGEEND
PAGE
PCWORD
PCPAGE
PCMSB
PAGEMSB
PROGRAM
COUNTER
COUNTER