ATmega324P datasheet(18/377 Pages) ATMEL

18 / 377 page

7674F–AVR–09/09

ATmega164P/324P/644P

AVR Memories

6.1

Overview

This section describes the different memories in the ATmega164P/324P/644P. The AVR archi-

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

addition, the ATmega164P/324P/644P features an EEPROM Memory for data storage. All three

memory spaces are linear and regular.

6.2

In-System Reprogrammable Flash Program Memory

The ATmega164P/324P/644P contains 16/32/64K bytes On-chip In-System Reprogrammable

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

is organized as 32/64 x 16. For software security, the Flash Program memory space is divided

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

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

ATmega164P/324P/644P Program Counter (PC) is 15/16 bits wide, thus addressing the 32/64K

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

bits for software protection are described in detail in “Memory Programming” on page 296.

“Memory Programming” on page 296 contains a detailed description on Flash data serial down-

loading 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 Execution Tim-

ing” on page 14.

ATmega324P Datasheet(PDF) 18 Page - ATMEL Corporation