382
XMEGA B [DATASHEET]
8291B–AVR–01/2013
For flash read operations (ELPM and LPM), one byte is read at a time. For this, the least-significant bit (bit 0) in the Z-
pointer is used to select the low byte or high byte in the word address. If this bit is 0, the low byte is read, and if this bit is
1 the high byte is read.
The size of FWORD and FPAGE will depend on the page and flash size in the device. Refer to each device’s datasheet
for details.
Once a programming operation is initiated, the address is latched and the Z-pointer can be updated and used for other
operations.
Figure 30-1. Flash addressing for self-programming.
30.11.2 NVM Flash Commands
The NVM commands that can be used for accessing the flash program memory, signature row and production signature
row are listed in
For self-programming of the flash, the trigger for action-triggered commands is to set the CMDEX bit in the NVM CTRLA
register (CMDEX). The read-triggered commands are triggered by executing the (E)LPM instruction (LPM). The write-
triggered commands are triggered by executing the SPM instruction (SPM).
The Change Protected column indicates whether the trigger is protected by the configuration change protection (CCP) or
not. This is a special sequence to write/execute the trigger during self-programming. For more details, refer to
Configuration Change Protection register” on page 15
. CCP is not required for external programming. The two last
columns show the address pointer used for addressing and the source/destination data register.
through
Section 30.11.2.14 on page 386
explain in detail the algorithm for each NVM
operation.
FPAGE
FWORD
0/1
BIT
Z-Pointer
0
B
S
M
D
R
O
W
B
S
M
E
G
A
P
1
INSTRUCTION WORD
PAGE
PAGE
PROGRAM MEMORY
WORD ADDRESS
WITHIN A PAGE
PAGE ADDRESS
WITHIN THE FLASH
FWORD
00
01
02
PAGEEND
00
01
02
FLASHEND
FPAGE
Low/High Byte select for (E)LPM
Summary of Contents for XMEGA B
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