Datasheet

 2018 Microchip Technology Inc. Data Sheet Complete DS40002058A-page 18
ATxmega128A1U/ATxmega64A1U
A separate memory section contains the fuse bytes. These are used for configuring important system functions, and can
only be written by an external programmer.
The available memory size configurations are shown in “Ordering Information” on page 8. In addition each device has a
flash memory signature rows for calibration data, device identification, serial number etc.
7.3 Flash Program Memory
The AVR XMEGA devices contain on-chip, in-system reprogrammable flash memory for program storage. The flash mem-
ory can be accessed for read and write from an external programmer through the PDI or from application software running
in the device.
All AVR CPU instructions are 16 or 32 bits wide, and each flash location is 16 bits wide. The flash memory is organized in
two main sections, the application section and the boot loader section. The sizes of the different sections are fixed, but
device-dependent. These two sections have separate lock bits, and can have different levels of protection. The store pro-
gram memory (SPM) instruction, which is used to write to the flash from the application software, will only operate when
executed from the boot loader section.
The application section contains an application table section with separate lock settings. This enables safe storage of non-
volatile data in the program memory.
Figure 7-1. Flash program memory (Hexadecimal address).
7.3.1 Application Section
The Application section is the section of the flash that is used for storing the executable application code. The protection
level for the application section can be selected by the boot lock bits for this section. The application section can not store
any boot loader code since the SPM instruction cannot be executed from the application section.
7.3.2 Application Table Section
The application table section is a part of the application section of the flash memory that can be used for storing data. The
size is identical to the boot loader section. The protection level for the application table section can be selected by the boot
lock bits for this section. The possibilities for different protection levels on the application section and the application table
section enable safe parameter storage in the program memory. If this section is not used for data, application code can
reside here.
Word Address
ATxmega128A1U ATxmega64A1U
0 0
Application Section (bytes)
(128K/64K)
...
EFFF / 77FF
F000 / 7800
Application Table Section (bytes) (8K/
4K)
FFFF / 7FFF
10000 / 8000
Boot Section (bytes)
(8K/4K)
10FFF / 87FF