ATXMEGA16E5_14 Datasheet, PDF (8/147 Pages) ATMEL Corporation – 8/16-bit Atmel AVR XMEGA Microcontrollers

Figure 7-1. Block Diagram of the AVR CPU architecture.
The arithmetic logic unit (ALU) supports arithmetic and logic operations between registers or between a constant and a
register. Single-register operations can also be executed in the ALU. After an arithmetic operation, the status register is
updated to reflect information about the result of the operation.
The ALU is directly connected to the fast-access register file. The 32 x 8-bit general purpose working registers all have
single clock cycle access time allowing single-cycle arithmetic logic unit (ALU) operation between registers or between a
register and an immediate. Six of the 32 registers can be used as three 16-bit address pointers for program and data
space addressing, enabling efficient address calculations.
The memory spaces are linear. The data memory space and the program memory space are two different memory
spaces.
The data memory space is divided into I/O registers, SRAM, and memory mapped EEPROM.
All I/O status and control registers reside in the lowest 4KB addresses of the data memory. This is referred to as the I/O
memory space. The lowest 64 addresses can be accessed directly, or as the data space locations from 0x00 to 0x3F.
The rest is the extended I/O memory space, ranging from 0x0040 to 0x0FFF. I/O registers here must be accessed as
data space locations using load (LD/LDS/LDD) and store (ST/STS/STD) instructions.
The SRAM holds data. Code execution from SRAM is not supported. It can easily be accessed through the five different
addressing modes supported in the AVR architecture. The first SRAM address is 0x2000.
Data addresses 0x1000 to 0x1FFF are reserved for EEPROM.
The program memory is divided in two sections, the application program section and the boot program section. Both
sections have dedicated lock bits for write and read/write protection. The SPM instruction that is used for self-
programming of the application flash memory must reside in the boot program section. The application section contains
an application table section with separate lock bits for write and read/write protection. The application table section can
be used for save storing of nonvolatile data in the program memory.
XMEGA E5 [DATASHEET]
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Atmel-8153I–AVR-ATxmega8E5-ATxmega16E5-ATxmega32E5_Datasheet–08/2014