ATmega165 datasheet(15/336 Pages) ATMEL

15 / 336 page

ATmega165/V

2573G–AVR–07/09

AVR ATmega165

Memories

This section describes the different memories in the ATmega165. The AVR architecture

has two main memory spaces, the Data Memory and the Program Memory space. In

addition, the ATmega165 features an EEPROM Memory for data storage. All three

memory spaces are linear and regular.

In-System

Reprogrammable Flash

Program Memory

The ATmega165 contains 16K bytes On-chip In-System Reprogrammable Flash mem-

ory for program storage. Since all AVR instructions are 16 or 32 bits wide, the Flash is

organized as 8K x 16. For software security, the Flash Program memory space is

divided into two sections, Boot Program section and Application Program section.

The Flash memory has an endurance of at least 10,000 write/erase cycles. The

ATmega165 Program Counter (PC) is 13 bits wide, thus addressing the 8K program

memory locations. The operation of Boot Program section and associated Boot Lock

bits for software protection are described in detail in “Boot Loader Support – Read-

While-Write Self-Programming” on page 232. “Memory Programming” on page 246 con-

tains a detailed description on Flash data serial downloading using the SPI pins or the

JTAG interface.

Constant tables can be allocated within the entire program memory address space (see

the LPM – Load Program Memory instruction description).

Timing diagrams for instruction fetch and execution are presented in “Instruction Execu-

tion Timing” on page 12.

Figure 8. Program Memory Map

0x0000

0x1FFF

Program Memory

Application Flash Section

Boot Flash Section

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