AI Interactive Datasheet ATmega2561
AVR · megaAVR

ATmega2561 memory map

Where everything sits, at its exact address. The ATmega2561 keeps program and data apart (Harvard): flash is read in words by the CPU, while registers, I/O and SRAM share one data address space.

Program memory

Flash, with the boot section at its top. Addresses in bytes.

Boot section0x3E000 – 0x3FFFF8 KB
Flash0x0000 – 0x3FFFF256 KB

Data memory

Working registers, I/O registers and SRAM in one space.

External RAM0x2200 – 0xFFFF55.5 KB
SRAM0x0200 – 0x21FF8 KB
I/O registers0x0020 – 0x01FF480 B
Working registers R0–R310x0000 – 0x001F32 B

EEPROM

Non-volatile data, kept without power.

EEPROM0x0000 – 0x0FFF4 KB

Every segment

SegmentSpaceStartEndSizePage
Working registers R0–R31data0x00000x001F32 B
I/O registersdata0x00200x01FF480 B
SRAMdata0x02000x21FF8 KB
External RAMdata0x22000xFFFF55.5 KB
EEPROMeeprom0x00000x0FFF4 KB8 B
FUSESfuses0x00000x00023 B
LOCKBITSlockbits0x00000x00001 B
OSCCALosccal0x00000x00001 B
Flashprog0x00000x3FFFF256 KB256 B
Boot sectionprog0x3E0000x3FFFF8 KB256 B
Boot sectionprog0x3F0000x3FFFF4 KB256 B
Boot sectionprog0x3F8000x3FFFF2 KB256 B
Boot sectionprog0x3FC000x3FFFF1 KB256 B
SIGNATURESsignatures0x00000x00023 B