5
32166A–AVR32806–06/11
Atmel AVR32806
6. Inner workings
6.1 Memory layout
An
part with the preprogrammed boot loader resets as any other part, at
80000000h. Boot loader execution begins here. The boot loader first performs the boot process
to know whether it should start the USB DFU ISP or the application. If the tested conditions indi-
cate that the USB DFU ISP should be started, then execution continues in the boot loader area
between 80000000h and 80002000h; else the boot loader launches the application at
80002000h.
The conditions tested by the boot process are configured by two 32-bit configuration words
located at the end of the flash user page.
Figure 6-1.
The
non-volatile memory layout with USB DFU boot
loader.
6.2 Configuration
The boot loader configuration is non-volatile and determines the behavior of the boot process
and the ISP. This configuration is stored in the 32 general purpose fuse bits and in the flash user
page (see
See the AVR UC3 datasheets for further information about the general purpose fuse bits and the
flash user page.
Application
Bootloader
Reset vector is
@ 80000000h
Application is
@ 80002000h
Flash User Page
Free Flash Space
User page is
@ 80800000h
32-bit bootloader
configuration word1 is
@ 808001FCh &
configuration word2 is
@ 808001F8h
32 GP Fuse
Bits
MCU Address Space
256kB
-Flash
Array
248 kB
8 kB
512 B
