ATMEGA649 datasheet(17/375 Pages) ATMEL

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ATmega329/3290/649/6490

2552H–AVR–11/06

AVR ATmega329/3290/649/6490 Memories

This section describes the different memories in the ATmega329/3290/649/6490. The

AVR architecture has two main memory spaces, the Data Memory and the Program

Memory space. In addition, the ATmega329/3290/649/6490 features an EEPROM

Memory for data storage. All three memory spaces are linear.

In-System

Reprogrammable Flash

Program Memory

The ATmega329/3290/649/6490 contains 32/64K bytes On-chip In-System Reprogram-

mable Flash memory for program storage. Since all AVR instructions are 16 or 32 bits

wide, the Flash is organized as 16/32K x 16. For software security, the Flash Program

memory space is divided into two sections, Boot Program section and Application Pro-

gram section.

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

ATmega329/3290/649/6490 Program Counter (PC) is 14/15 bits wide, thus addressing

the 16/32K 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 268. “Memory Programming”

on page 281 contains 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 14.

Figure 9. Program Memory Map

0x0000

0x3FFF/0x7FFF

Program Memory

Application Flash Section

Boot Flash Section

ATMEGA649 Datasheet(PDF) 17 Page - ATMEL Corporation