MEGA128CAN datasheet(16/413 Pages) ATMEL

16 / 413 page

AT90CAN128

4250E–CAN–12/04

Memories

This section describes the different memories in the AT90CAN128. The AVR architec-

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

In addition, the AT90CAN128 features an EEPROM Memory for data storage. All three

memory spaces are linear and regular.

In-System

Reprogrammable Flash

Program Memory

The AT90CAN128 contains 128K 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 64K 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

AT90CAN128 Program Counter (PC) is 16 bits wide, thus addressing the 64K 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 311. “Memory Programming” on page 325 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 and ELPM – Extended Load Program Memory

instruction description).

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

tion Timing” on page 13.

Figure 9. Program Memory Map

0x0000

0xFFFF

Program Memory

Application Flash Section

Boot Flash Section

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