8.3 In-System Reprogrammable Flash Program Memory

The AVR128DB28/32/48/64 contains 128 KB on-chip in-system reprogrammable Flash memory for program storage. Since all AVR instructions are 16 or 32 bits wide, the Flash is organized with 16-bit data width. For write protection, the Flash program memory space can be divided into three sections: Boot Code section, Application Code section, and Application Data section. Code placed in one section may be restricted from writing to addresses in other sections. The Program Counter (PC) can address the whole program memory.

Refer to the Code Size (CODESIZE) and Boot Size (BOOTSIZE) descriptions and the Nonvolatile Memory Controller section for further details.

The Program Counter can address the whole program memory. The procedure for writing Flash memory is described in detail in the Nonvolatile Memory Controller (NVMCTRL) peripheral documentation.

Each 32 KB section from Flash memory is mapped into the data memory space and is accessible with LD/ST instructions. For LD/ST instructions, the Flash is mapped from address 0x8000 to 0xFFFF. The entire Flash memory space can be accessed with the LPM/SPM instruction. For the LPM/SPM instruction, the Flash start address is 0x0000.