ATMEGA406_0607 datasheet(16/263 Pages) ATMEL

16 / 263 page

2548E–AVR–07/06

ATmega406

AVR Memories

This section describes the different memories in the ATmega406. The AVR architecture has two

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

ATmega406 features an EEPROM Memory for data storage. All three memory spaces are linear

and regular.

6.1

In-System Reprogrammable Flash Program Memory

The ATmega406 contains 40K 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

20K 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 ATmega406

Program Counter (PC) is 15 bits wide, thus addressing the 20K 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

178. ”Memory Programming” on page 195 contains a detailed description on Flash data serial

downloading.

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 13.

Figure 6-1.

Program Memory Map

0x0000

0x4FFF

Program Memory

Application Flash Section

Boot Flash Section

ATMEGA406_0607 Datasheet(PDF) 16 Page - ATMEL Corporation